4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/mutex.h>
30 #include <linux/of_device.h>
31 #include <linux/of_irq.h>
32 #include <linux/slab.h>
33 #include <linux/mod_devicetable.h>
34 #include <linux/spi/spi.h>
35 #include <linux/of_gpio.h>
36 #include <linux/pm_runtime.h>
37 #include <linux/export.h>
38 #include <linux/sched/rt.h>
39 #include <linux/delay.h>
40 #include <linux/kthread.h>
41 #include <linux/ioport.h>
42 #include <linux/acpi.h>
44 #define CREATE_TRACE_POINTS
45 #include <trace/events/spi.h>
47 static void spidev_release(struct device
*dev
)
49 struct spi_device
*spi
= to_spi_device(dev
);
51 /* spi masters may cleanup for released devices */
52 if (spi
->master
->cleanup
)
53 spi
->master
->cleanup(spi
);
55 spi_master_put(spi
->master
);
60 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
62 const struct spi_device
*spi
= to_spi_device(dev
);
65 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
- 1);
69 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
71 static DEVICE_ATTR_RO(modalias
);
73 static struct attribute
*spi_dev_attrs
[] = {
74 &dev_attr_modalias
.attr
,
77 ATTRIBUTE_GROUPS(spi_dev
);
79 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
80 * and the sysfs version makes coldplug work too.
83 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
84 const struct spi_device
*sdev
)
87 if (!strcmp(sdev
->modalias
, id
->name
))
94 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
96 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
98 return spi_match_id(sdrv
->id_table
, sdev
);
100 EXPORT_SYMBOL_GPL(spi_get_device_id
);
102 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
104 const struct spi_device
*spi
= to_spi_device(dev
);
105 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
107 /* Attempt an OF style match */
108 if (of_driver_match_device(dev
, drv
))
112 if (acpi_driver_match_device(dev
, drv
))
116 return !!spi_match_id(sdrv
->id_table
, spi
);
118 return strcmp(spi
->modalias
, drv
->name
) == 0;
121 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
123 const struct spi_device
*spi
= to_spi_device(dev
);
126 rc
= acpi_device_uevent_modalias(dev
, env
);
130 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
134 #ifdef CONFIG_PM_SLEEP
135 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
138 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
140 /* suspend will stop irqs and dma; no more i/o */
143 value
= drv
->suspend(to_spi_device(dev
), message
);
145 dev_dbg(dev
, "... can't suspend\n");
150 static int spi_legacy_resume(struct device
*dev
)
153 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
155 /* resume may restart the i/o queue */
158 value
= drv
->resume(to_spi_device(dev
));
160 dev_dbg(dev
, "... can't resume\n");
165 static int spi_pm_suspend(struct device
*dev
)
167 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
170 return pm_generic_suspend(dev
);
172 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
175 static int spi_pm_resume(struct device
*dev
)
177 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
180 return pm_generic_resume(dev
);
182 return spi_legacy_resume(dev
);
185 static int spi_pm_freeze(struct device
*dev
)
187 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
190 return pm_generic_freeze(dev
);
192 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
195 static int spi_pm_thaw(struct device
*dev
)
197 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
200 return pm_generic_thaw(dev
);
202 return spi_legacy_resume(dev
);
205 static int spi_pm_poweroff(struct device
*dev
)
207 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
210 return pm_generic_poweroff(dev
);
212 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
215 static int spi_pm_restore(struct device
*dev
)
217 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
220 return pm_generic_restore(dev
);
222 return spi_legacy_resume(dev
);
225 #define spi_pm_suspend NULL
226 #define spi_pm_resume NULL
227 #define spi_pm_freeze NULL
228 #define spi_pm_thaw NULL
229 #define spi_pm_poweroff NULL
230 #define spi_pm_restore NULL
233 static const struct dev_pm_ops spi_pm
= {
234 .suspend
= spi_pm_suspend
,
235 .resume
= spi_pm_resume
,
236 .freeze
= spi_pm_freeze
,
238 .poweroff
= spi_pm_poweroff
,
239 .restore
= spi_pm_restore
,
241 pm_generic_runtime_suspend
,
242 pm_generic_runtime_resume
,
247 struct bus_type spi_bus_type
= {
249 .dev_groups
= spi_dev_groups
,
250 .match
= spi_match_device
,
251 .uevent
= spi_uevent
,
254 EXPORT_SYMBOL_GPL(spi_bus_type
);
257 static int spi_drv_probe(struct device
*dev
)
259 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
262 acpi_dev_pm_attach(dev
, true);
263 ret
= sdrv
->probe(to_spi_device(dev
));
265 acpi_dev_pm_detach(dev
, true);
270 static int spi_drv_remove(struct device
*dev
)
272 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
275 ret
= sdrv
->remove(to_spi_device(dev
));
276 acpi_dev_pm_detach(dev
, true);
281 static void spi_drv_shutdown(struct device
*dev
)
283 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
285 sdrv
->shutdown(to_spi_device(dev
));
289 * spi_register_driver - register a SPI driver
290 * @sdrv: the driver to register
293 int spi_register_driver(struct spi_driver
*sdrv
)
295 sdrv
->driver
.bus
= &spi_bus_type
;
297 sdrv
->driver
.probe
= spi_drv_probe
;
299 sdrv
->driver
.remove
= spi_drv_remove
;
301 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
302 return driver_register(&sdrv
->driver
);
304 EXPORT_SYMBOL_GPL(spi_register_driver
);
306 /*-------------------------------------------------------------------------*/
308 /* SPI devices should normally not be created by SPI device drivers; that
309 * would make them board-specific. Similarly with SPI master drivers.
310 * Device registration normally goes into like arch/.../mach.../board-YYY.c
311 * with other readonly (flashable) information about mainboard devices.
315 struct list_head list
;
316 struct spi_board_info board_info
;
319 static LIST_HEAD(board_list
);
320 static LIST_HEAD(spi_master_list
);
323 * Used to protect add/del opertion for board_info list and
324 * spi_master list, and their matching process
326 static DEFINE_MUTEX(board_lock
);
329 * spi_alloc_device - Allocate a new SPI device
330 * @master: Controller to which device is connected
333 * Allows a driver to allocate and initialize a spi_device without
334 * registering it immediately. This allows a driver to directly
335 * fill the spi_device with device parameters before calling
336 * spi_add_device() on it.
338 * Caller is responsible to call spi_add_device() on the returned
339 * spi_device structure to add it to the SPI master. If the caller
340 * needs to discard the spi_device without adding it, then it should
341 * call spi_dev_put() on it.
343 * Returns a pointer to the new device, or NULL.
345 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
347 struct spi_device
*spi
;
348 struct device
*dev
= master
->dev
.parent
;
350 if (!spi_master_get(master
))
353 spi
= kzalloc(sizeof(*spi
), GFP_KERNEL
);
355 dev_err(dev
, "cannot alloc spi_device\n");
356 spi_master_put(master
);
360 spi
->master
= master
;
361 spi
->dev
.parent
= &master
->dev
;
362 spi
->dev
.bus
= &spi_bus_type
;
363 spi
->dev
.release
= spidev_release
;
364 spi
->cs_gpio
= -ENOENT
;
365 device_initialize(&spi
->dev
);
368 EXPORT_SYMBOL_GPL(spi_alloc_device
);
370 static void spi_dev_set_name(struct spi_device
*spi
)
372 struct acpi_device
*adev
= ACPI_COMPANION(&spi
->dev
);
375 dev_set_name(&spi
->dev
, "spi-%s", acpi_dev_name(adev
));
379 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
383 static int spi_dev_check(struct device
*dev
, void *data
)
385 struct spi_device
*spi
= to_spi_device(dev
);
386 struct spi_device
*new_spi
= data
;
388 if (spi
->master
== new_spi
->master
&&
389 spi
->chip_select
== new_spi
->chip_select
)
395 * spi_add_device - Add spi_device allocated with spi_alloc_device
396 * @spi: spi_device to register
398 * Companion function to spi_alloc_device. Devices allocated with
399 * spi_alloc_device can be added onto the spi bus with this function.
401 * Returns 0 on success; negative errno on failure
403 int spi_add_device(struct spi_device
*spi
)
405 static DEFINE_MUTEX(spi_add_lock
);
406 struct spi_master
*master
= spi
->master
;
407 struct device
*dev
= master
->dev
.parent
;
410 /* Chipselects are numbered 0..max; validate. */
411 if (spi
->chip_select
>= master
->num_chipselect
) {
412 dev_err(dev
, "cs%d >= max %d\n",
414 master
->num_chipselect
);
418 /* Set the bus ID string */
419 spi_dev_set_name(spi
);
421 /* We need to make sure there's no other device with this
422 * chipselect **BEFORE** we call setup(), else we'll trash
423 * its configuration. Lock against concurrent add() calls.
425 mutex_lock(&spi_add_lock
);
427 status
= bus_for_each_dev(&spi_bus_type
, NULL
, spi
, spi_dev_check
);
429 dev_err(dev
, "chipselect %d already in use\n",
434 if (master
->cs_gpios
)
435 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
437 /* Drivers may modify this initial i/o setup, but will
438 * normally rely on the device being setup. Devices
439 * using SPI_CS_HIGH can't coexist well otherwise...
441 status
= spi_setup(spi
);
443 dev_err(dev
, "can't setup %s, status %d\n",
444 dev_name(&spi
->dev
), status
);
448 /* Device may be bound to an active driver when this returns */
449 status
= device_add(&spi
->dev
);
451 dev_err(dev
, "can't add %s, status %d\n",
452 dev_name(&spi
->dev
), status
);
454 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
457 mutex_unlock(&spi_add_lock
);
460 EXPORT_SYMBOL_GPL(spi_add_device
);
463 * spi_new_device - instantiate one new SPI device
464 * @master: Controller to which device is connected
465 * @chip: Describes the SPI device
468 * On typical mainboards, this is purely internal; and it's not needed
469 * after board init creates the hard-wired devices. Some development
470 * platforms may not be able to use spi_register_board_info though, and
471 * this is exported so that for example a USB or parport based adapter
472 * driver could add devices (which it would learn about out-of-band).
474 * Returns the new device, or NULL.
476 struct spi_device
*spi_new_device(struct spi_master
*master
,
477 struct spi_board_info
*chip
)
479 struct spi_device
*proxy
;
482 /* NOTE: caller did any chip->bus_num checks necessary.
484 * Also, unless we change the return value convention to use
485 * error-or-pointer (not NULL-or-pointer), troubleshootability
486 * suggests syslogged diagnostics are best here (ugh).
489 proxy
= spi_alloc_device(master
);
493 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
495 proxy
->chip_select
= chip
->chip_select
;
496 proxy
->max_speed_hz
= chip
->max_speed_hz
;
497 proxy
->mode
= chip
->mode
;
498 proxy
->irq
= chip
->irq
;
499 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
500 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
501 proxy
->controller_data
= chip
->controller_data
;
502 proxy
->controller_state
= NULL
;
504 status
= spi_add_device(proxy
);
512 EXPORT_SYMBOL_GPL(spi_new_device
);
514 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
515 struct spi_board_info
*bi
)
517 struct spi_device
*dev
;
519 if (master
->bus_num
!= bi
->bus_num
)
522 dev
= spi_new_device(master
, bi
);
524 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
529 * spi_register_board_info - register SPI devices for a given board
530 * @info: array of chip descriptors
531 * @n: how many descriptors are provided
534 * Board-specific early init code calls this (probably during arch_initcall)
535 * with segments of the SPI device table. Any device nodes are created later,
536 * after the relevant parent SPI controller (bus_num) is defined. We keep
537 * this table of devices forever, so that reloading a controller driver will
538 * not make Linux forget about these hard-wired devices.
540 * Other code can also call this, e.g. a particular add-on board might provide
541 * SPI devices through its expansion connector, so code initializing that board
542 * would naturally declare its SPI devices.
544 * The board info passed can safely be __initdata ... but be careful of
545 * any embedded pointers (platform_data, etc), they're copied as-is.
547 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
549 struct boardinfo
*bi
;
552 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
556 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
557 struct spi_master
*master
;
559 memcpy(&bi
->board_info
, info
, sizeof(*info
));
560 mutex_lock(&board_lock
);
561 list_add_tail(&bi
->list
, &board_list
);
562 list_for_each_entry(master
, &spi_master_list
, list
)
563 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
564 mutex_unlock(&board_lock
);
570 /*-------------------------------------------------------------------------*/
572 static void spi_set_cs(struct spi_device
*spi
, bool enable
)
574 if (spi
->mode
& SPI_CS_HIGH
)
577 if (spi
->cs_gpio
>= 0)
578 gpio_set_value(spi
->cs_gpio
, !enable
);
579 else if (spi
->master
->set_cs
)
580 spi
->master
->set_cs(spi
, !enable
);
583 #ifdef CONFIG_HAS_DMA
584 static int spi_map_buf(struct spi_master
*master
, struct device
*dev
,
585 struct sg_table
*sgt
, void *buf
, size_t len
,
586 enum dma_data_direction dir
)
588 const bool vmalloced_buf
= is_vmalloc_addr(buf
);
589 const int desc_len
= vmalloced_buf
? PAGE_SIZE
: master
->max_dma_len
;
590 const int sgs
= DIV_ROUND_UP(len
, desc_len
);
591 struct page
*vm_page
;
596 ret
= sg_alloc_table(sgt
, sgs
, GFP_KERNEL
);
600 for (i
= 0; i
< sgs
; i
++) {
601 min
= min_t(size_t, len
, desc_len
);
604 vm_page
= vmalloc_to_page(buf
);
609 sg_buf
= page_address(vm_page
) +
610 ((size_t)buf
& ~PAGE_MASK
);
615 sg_set_buf(&sgt
->sgl
[i
], sg_buf
, min
);
621 ret
= dma_map_sg(dev
, sgt
->sgl
, sgt
->nents
, dir
);
632 static void spi_unmap_buf(struct spi_master
*master
, struct device
*dev
,
633 struct sg_table
*sgt
, enum dma_data_direction dir
)
635 if (sgt
->orig_nents
) {
636 dma_unmap_sg(dev
, sgt
->sgl
, sgt
->orig_nents
, dir
);
641 static int __spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
643 struct device
*tx_dev
, *rx_dev
;
644 struct spi_transfer
*xfer
;
647 if (!master
->can_dma
)
650 tx_dev
= &master
->dma_tx
->dev
->device
;
651 rx_dev
= &master
->dma_rx
->dev
->device
;
653 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
654 if (!master
->can_dma(master
, msg
->spi
, xfer
))
657 if (xfer
->tx_buf
!= NULL
) {
658 ret
= spi_map_buf(master
, tx_dev
, &xfer
->tx_sg
,
659 (void *)xfer
->tx_buf
, xfer
->len
,
665 if (xfer
->rx_buf
!= NULL
) {
666 ret
= spi_map_buf(master
, rx_dev
, &xfer
->rx_sg
,
667 xfer
->rx_buf
, xfer
->len
,
670 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
,
677 master
->cur_msg_mapped
= true;
682 static int spi_unmap_msg(struct spi_master
*master
, struct spi_message
*msg
)
684 struct spi_transfer
*xfer
;
685 struct device
*tx_dev
, *rx_dev
;
687 if (!master
->cur_msg_mapped
|| !master
->can_dma
)
690 tx_dev
= &master
->dma_tx
->dev
->device
;
691 rx_dev
= &master
->dma_rx
->dev
->device
;
693 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
694 if (!master
->can_dma(master
, msg
->spi
, xfer
))
697 spi_unmap_buf(master
, rx_dev
, &xfer
->rx_sg
, DMA_FROM_DEVICE
);
698 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
, DMA_TO_DEVICE
);
703 #else /* !CONFIG_HAS_DMA */
704 static inline int __spi_map_msg(struct spi_master
*master
,
705 struct spi_message
*msg
)
710 static inline int spi_unmap_msg(struct spi_master
*master
,
711 struct spi_message
*msg
)
715 #endif /* !CONFIG_HAS_DMA */
717 static int spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
719 struct spi_transfer
*xfer
;
721 unsigned int max_tx
, max_rx
;
723 if (master
->flags
& (SPI_MASTER_MUST_RX
| SPI_MASTER_MUST_TX
)) {
727 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
728 if ((master
->flags
& SPI_MASTER_MUST_TX
) &&
730 max_tx
= max(xfer
->len
, max_tx
);
731 if ((master
->flags
& SPI_MASTER_MUST_RX
) &&
733 max_rx
= max(xfer
->len
, max_rx
);
737 tmp
= krealloc(master
->dummy_tx
, max_tx
,
738 GFP_KERNEL
| GFP_DMA
);
741 master
->dummy_tx
= tmp
;
742 memset(tmp
, 0, max_tx
);
746 tmp
= krealloc(master
->dummy_rx
, max_rx
,
747 GFP_KERNEL
| GFP_DMA
);
750 master
->dummy_rx
= tmp
;
753 if (max_tx
|| max_rx
) {
754 list_for_each_entry(xfer
, &msg
->transfers
,
757 xfer
->tx_buf
= master
->dummy_tx
;
759 xfer
->rx_buf
= master
->dummy_rx
;
764 return __spi_map_msg(master
, msg
);
768 * spi_transfer_one_message - Default implementation of transfer_one_message()
770 * This is a standard implementation of transfer_one_message() for
771 * drivers which impelment a transfer_one() operation. It provides
772 * standard handling of delays and chip select management.
774 static int spi_transfer_one_message(struct spi_master
*master
,
775 struct spi_message
*msg
)
777 struct spi_transfer
*xfer
;
778 bool keep_cs
= false;
782 spi_set_cs(msg
->spi
, true);
784 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
785 trace_spi_transfer_start(msg
, xfer
);
787 reinit_completion(&master
->xfer_completion
);
789 ret
= master
->transfer_one(master
, msg
->spi
, xfer
);
791 dev_err(&msg
->spi
->dev
,
792 "SPI transfer failed: %d\n", ret
);
798 ms
= xfer
->len
* 8 * 1000 / xfer
->speed_hz
;
799 ms
+= ms
+ 100; /* some tolerance */
801 ms
= wait_for_completion_timeout(&master
->xfer_completion
,
802 msecs_to_jiffies(ms
));
806 dev_err(&msg
->spi
->dev
, "SPI transfer timed out\n");
807 msg
->status
= -ETIMEDOUT
;
810 trace_spi_transfer_stop(msg
, xfer
);
812 if (msg
->status
!= -EINPROGRESS
)
815 if (xfer
->delay_usecs
)
816 udelay(xfer
->delay_usecs
);
818 if (xfer
->cs_change
) {
819 if (list_is_last(&xfer
->transfer_list
,
823 spi_set_cs(msg
->spi
, false);
825 spi_set_cs(msg
->spi
, true);
829 msg
->actual_length
+= xfer
->len
;
833 if (ret
!= 0 || !keep_cs
)
834 spi_set_cs(msg
->spi
, false);
836 if (msg
->status
== -EINPROGRESS
)
839 spi_finalize_current_message(master
);
845 * spi_finalize_current_transfer - report completion of a transfer
847 * Called by SPI drivers using the core transfer_one_message()
848 * implementation to notify it that the current interrupt driven
849 * transfer has finished and the next one may be scheduled.
851 void spi_finalize_current_transfer(struct spi_master
*master
)
853 complete(&master
->xfer_completion
);
855 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer
);
858 * spi_pump_messages - kthread work function which processes spi message queue
859 * @work: pointer to kthread work struct contained in the master struct
861 * This function checks if there is any spi message in the queue that
862 * needs processing and if so call out to the driver to initialize hardware
863 * and transfer each message.
866 static void spi_pump_messages(struct kthread_work
*work
)
868 struct spi_master
*master
=
869 container_of(work
, struct spi_master
, pump_messages
);
871 bool was_busy
= false;
874 /* Lock queue and check for queue work */
875 spin_lock_irqsave(&master
->queue_lock
, flags
);
876 if (list_empty(&master
->queue
) || !master
->running
) {
878 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
881 master
->busy
= false;
882 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
883 kfree(master
->dummy_rx
);
884 master
->dummy_rx
= NULL
;
885 kfree(master
->dummy_tx
);
886 master
->dummy_tx
= NULL
;
887 if (master
->unprepare_transfer_hardware
&&
888 master
->unprepare_transfer_hardware(master
))
889 dev_err(&master
->dev
,
890 "failed to unprepare transfer hardware\n");
891 if (master
->auto_runtime_pm
) {
892 pm_runtime_mark_last_busy(master
->dev
.parent
);
893 pm_runtime_put_autosuspend(master
->dev
.parent
);
895 trace_spi_master_idle(master
);
899 /* Make sure we are not already running a message */
900 if (master
->cur_msg
) {
901 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
904 /* Extract head of queue */
906 list_first_entry(&master
->queue
, struct spi_message
, queue
);
908 list_del_init(&master
->cur_msg
->queue
);
913 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
915 if (!was_busy
&& master
->auto_runtime_pm
) {
916 ret
= pm_runtime_get_sync(master
->dev
.parent
);
918 dev_err(&master
->dev
, "Failed to power device: %d\n",
925 trace_spi_master_busy(master
);
927 if (!was_busy
&& master
->prepare_transfer_hardware
) {
928 ret
= master
->prepare_transfer_hardware(master
);
930 dev_err(&master
->dev
,
931 "failed to prepare transfer hardware\n");
933 if (master
->auto_runtime_pm
)
934 pm_runtime_put(master
->dev
.parent
);
939 trace_spi_message_start(master
->cur_msg
);
941 if (master
->prepare_message
) {
942 ret
= master
->prepare_message(master
, master
->cur_msg
);
944 dev_err(&master
->dev
,
945 "failed to prepare message: %d\n", ret
);
946 master
->cur_msg
->status
= ret
;
947 spi_finalize_current_message(master
);
950 master
->cur_msg_prepared
= true;
953 ret
= spi_map_msg(master
, master
->cur_msg
);
955 master
->cur_msg
->status
= ret
;
956 spi_finalize_current_message(master
);
960 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
962 dev_err(&master
->dev
,
963 "failed to transfer one message from queue\n");
968 static int spi_init_queue(struct spi_master
*master
)
970 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
972 INIT_LIST_HEAD(&master
->queue
);
973 spin_lock_init(&master
->queue_lock
);
975 master
->running
= false;
976 master
->busy
= false;
978 init_kthread_worker(&master
->kworker
);
979 master
->kworker_task
= kthread_run(kthread_worker_fn
,
980 &master
->kworker
, "%s",
981 dev_name(&master
->dev
));
982 if (IS_ERR(master
->kworker_task
)) {
983 dev_err(&master
->dev
, "failed to create message pump task\n");
986 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
989 * Master config will indicate if this controller should run the
990 * message pump with high (realtime) priority to reduce the transfer
991 * latency on the bus by minimising the delay between a transfer
992 * request and the scheduling of the message pump thread. Without this
993 * setting the message pump thread will remain at default priority.
996 dev_info(&master
->dev
,
997 "will run message pump with realtime priority\n");
998 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
1005 * spi_get_next_queued_message() - called by driver to check for queued
1007 * @master: the master to check for queued messages
1009 * If there are more messages in the queue, the next message is returned from
1012 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
1014 struct spi_message
*next
;
1015 unsigned long flags
;
1017 /* get a pointer to the next message, if any */
1018 spin_lock_irqsave(&master
->queue_lock
, flags
);
1019 next
= list_first_entry_or_null(&master
->queue
, struct spi_message
,
1021 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1025 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
1028 * spi_finalize_current_message() - the current message is complete
1029 * @master: the master to return the message to
1031 * Called by the driver to notify the core that the message in the front of the
1032 * queue is complete and can be removed from the queue.
1034 void spi_finalize_current_message(struct spi_master
*master
)
1036 struct spi_message
*mesg
;
1037 unsigned long flags
;
1040 spin_lock_irqsave(&master
->queue_lock
, flags
);
1041 mesg
= master
->cur_msg
;
1042 master
->cur_msg
= NULL
;
1044 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1045 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1047 spi_unmap_msg(master
, mesg
);
1049 if (master
->cur_msg_prepared
&& master
->unprepare_message
) {
1050 ret
= master
->unprepare_message(master
, mesg
);
1052 dev_err(&master
->dev
,
1053 "failed to unprepare message: %d\n", ret
);
1056 master
->cur_msg_prepared
= false;
1060 mesg
->complete(mesg
->context
);
1062 trace_spi_message_done(mesg
);
1064 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
1066 static int spi_start_queue(struct spi_master
*master
)
1068 unsigned long flags
;
1070 spin_lock_irqsave(&master
->queue_lock
, flags
);
1072 if (master
->running
|| master
->busy
) {
1073 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1077 master
->running
= true;
1078 master
->cur_msg
= NULL
;
1079 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1081 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1086 static int spi_stop_queue(struct spi_master
*master
)
1088 unsigned long flags
;
1089 unsigned limit
= 500;
1092 spin_lock_irqsave(&master
->queue_lock
, flags
);
1095 * This is a bit lame, but is optimized for the common execution path.
1096 * A wait_queue on the master->busy could be used, but then the common
1097 * execution path (pump_messages) would be required to call wake_up or
1098 * friends on every SPI message. Do this instead.
1100 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
1101 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1102 usleep_range(10000, 11000);
1103 spin_lock_irqsave(&master
->queue_lock
, flags
);
1106 if (!list_empty(&master
->queue
) || master
->busy
)
1109 master
->running
= false;
1111 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1114 dev_warn(&master
->dev
,
1115 "could not stop message queue\n");
1121 static int spi_destroy_queue(struct spi_master
*master
)
1125 ret
= spi_stop_queue(master
);
1128 * flush_kthread_worker will block until all work is done.
1129 * If the reason that stop_queue timed out is that the work will never
1130 * finish, then it does no good to call flush/stop thread, so
1134 dev_err(&master
->dev
, "problem destroying queue\n");
1138 flush_kthread_worker(&master
->kworker
);
1139 kthread_stop(master
->kworker_task
);
1145 * spi_queued_transfer - transfer function for queued transfers
1146 * @spi: spi device which is requesting transfer
1147 * @msg: spi message which is to handled is queued to driver queue
1149 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
1151 struct spi_master
*master
= spi
->master
;
1152 unsigned long flags
;
1154 spin_lock_irqsave(&master
->queue_lock
, flags
);
1156 if (!master
->running
) {
1157 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1160 msg
->actual_length
= 0;
1161 msg
->status
= -EINPROGRESS
;
1163 list_add_tail(&msg
->queue
, &master
->queue
);
1165 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1167 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1171 static int spi_master_initialize_queue(struct spi_master
*master
)
1175 master
->transfer
= spi_queued_transfer
;
1176 if (!master
->transfer_one_message
)
1177 master
->transfer_one_message
= spi_transfer_one_message
;
1179 /* Initialize and start queue */
1180 ret
= spi_init_queue(master
);
1182 dev_err(&master
->dev
, "problem initializing queue\n");
1183 goto err_init_queue
;
1185 master
->queued
= true;
1186 ret
= spi_start_queue(master
);
1188 dev_err(&master
->dev
, "problem starting queue\n");
1189 goto err_start_queue
;
1195 spi_destroy_queue(master
);
1200 /*-------------------------------------------------------------------------*/
1202 #if defined(CONFIG_OF)
1204 * of_register_spi_devices() - Register child devices onto the SPI bus
1205 * @master: Pointer to spi_master device
1207 * Registers an spi_device for each child node of master node which has a 'reg'
1210 static void of_register_spi_devices(struct spi_master
*master
)
1212 struct spi_device
*spi
;
1213 struct device_node
*nc
;
1217 if (!master
->dev
.of_node
)
1220 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
1221 /* Alloc an spi_device */
1222 spi
= spi_alloc_device(master
);
1224 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
1230 /* Select device driver */
1231 if (of_modalias_node(nc
, spi
->modalias
,
1232 sizeof(spi
->modalias
)) < 0) {
1233 dev_err(&master
->dev
, "cannot find modalias for %s\n",
1239 /* Device address */
1240 rc
= of_property_read_u32(nc
, "reg", &value
);
1242 dev_err(&master
->dev
, "%s has no valid 'reg' property (%d)\n",
1247 spi
->chip_select
= value
;
1249 /* Mode (clock phase/polarity/etc.) */
1250 if (of_find_property(nc
, "spi-cpha", NULL
))
1251 spi
->mode
|= SPI_CPHA
;
1252 if (of_find_property(nc
, "spi-cpol", NULL
))
1253 spi
->mode
|= SPI_CPOL
;
1254 if (of_find_property(nc
, "spi-cs-high", NULL
))
1255 spi
->mode
|= SPI_CS_HIGH
;
1256 if (of_find_property(nc
, "spi-3wire", NULL
))
1257 spi
->mode
|= SPI_3WIRE
;
1258 if (of_find_property(nc
, "spi-lsb-first", NULL
))
1259 spi
->mode
|= SPI_LSB_FIRST
;
1261 /* Device DUAL/QUAD mode */
1262 if (!of_property_read_u32(nc
, "spi-tx-bus-width", &value
)) {
1267 spi
->mode
|= SPI_TX_DUAL
;
1270 spi
->mode
|= SPI_TX_QUAD
;
1273 dev_warn(&master
->dev
,
1274 "spi-tx-bus-width %d not supported\n",
1280 if (!of_property_read_u32(nc
, "spi-rx-bus-width", &value
)) {
1285 spi
->mode
|= SPI_RX_DUAL
;
1288 spi
->mode
|= SPI_RX_QUAD
;
1291 dev_warn(&master
->dev
,
1292 "spi-rx-bus-width %d not supported\n",
1299 rc
= of_property_read_u32(nc
, "spi-max-frequency", &value
);
1301 dev_err(&master
->dev
, "%s has no valid 'spi-max-frequency' property (%d)\n",
1306 spi
->max_speed_hz
= value
;
1309 spi
->irq
= irq_of_parse_and_map(nc
, 0);
1311 /* Store a pointer to the node in the device structure */
1313 spi
->dev
.of_node
= nc
;
1315 /* Register the new device */
1316 request_module("%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
1317 rc
= spi_add_device(spi
);
1319 dev_err(&master
->dev
, "spi_device register error %s\n",
1327 static void of_register_spi_devices(struct spi_master
*master
) { }
1331 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
1333 struct spi_device
*spi
= data
;
1335 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
1336 struct acpi_resource_spi_serialbus
*sb
;
1338 sb
= &ares
->data
.spi_serial_bus
;
1339 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
1340 spi
->chip_select
= sb
->device_selection
;
1341 spi
->max_speed_hz
= sb
->connection_speed
;
1343 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
1344 spi
->mode
|= SPI_CPHA
;
1345 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
1346 spi
->mode
|= SPI_CPOL
;
1347 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
1348 spi
->mode
|= SPI_CS_HIGH
;
1350 } else if (spi
->irq
< 0) {
1353 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
1357 /* Always tell the ACPI core to skip this resource */
1361 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
1362 void *data
, void **return_value
)
1364 struct spi_master
*master
= data
;
1365 struct list_head resource_list
;
1366 struct acpi_device
*adev
;
1367 struct spi_device
*spi
;
1370 if (acpi_bus_get_device(handle
, &adev
))
1372 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1375 spi
= spi_alloc_device(master
);
1377 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1378 dev_name(&adev
->dev
));
1379 return AE_NO_MEMORY
;
1382 ACPI_COMPANION_SET(&spi
->dev
, adev
);
1385 INIT_LIST_HEAD(&resource_list
);
1386 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1387 acpi_spi_add_resource
, spi
);
1388 acpi_dev_free_resource_list(&resource_list
);
1390 if (ret
< 0 || !spi
->max_speed_hz
) {
1395 adev
->power
.flags
.ignore_parent
= true;
1396 strlcpy(spi
->modalias
, acpi_device_hid(adev
), sizeof(spi
->modalias
));
1397 if (spi_add_device(spi
)) {
1398 adev
->power
.flags
.ignore_parent
= false;
1399 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1400 dev_name(&adev
->dev
));
1407 static void acpi_register_spi_devices(struct spi_master
*master
)
1412 handle
= ACPI_HANDLE(master
->dev
.parent
);
1416 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1417 acpi_spi_add_device
, NULL
,
1419 if (ACPI_FAILURE(status
))
1420 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1423 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1424 #endif /* CONFIG_ACPI */
1426 static void spi_master_release(struct device
*dev
)
1428 struct spi_master
*master
;
1430 master
= container_of(dev
, struct spi_master
, dev
);
1434 static struct class spi_master_class
= {
1435 .name
= "spi_master",
1436 .owner
= THIS_MODULE
,
1437 .dev_release
= spi_master_release
,
1443 * spi_alloc_master - allocate SPI master controller
1444 * @dev: the controller, possibly using the platform_bus
1445 * @size: how much zeroed driver-private data to allocate; the pointer to this
1446 * memory is in the driver_data field of the returned device,
1447 * accessible with spi_master_get_devdata().
1448 * Context: can sleep
1450 * This call is used only by SPI master controller drivers, which are the
1451 * only ones directly touching chip registers. It's how they allocate
1452 * an spi_master structure, prior to calling spi_register_master().
1454 * This must be called from context that can sleep. It returns the SPI
1455 * master structure on success, else NULL.
1457 * The caller is responsible for assigning the bus number and initializing
1458 * the master's methods before calling spi_register_master(); and (after errors
1459 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1462 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1464 struct spi_master
*master
;
1469 master
= kzalloc(size
+ sizeof(*master
), GFP_KERNEL
);
1473 device_initialize(&master
->dev
);
1474 master
->bus_num
= -1;
1475 master
->num_chipselect
= 1;
1476 master
->dev
.class = &spi_master_class
;
1477 master
->dev
.parent
= get_device(dev
);
1478 spi_master_set_devdata(master
, &master
[1]);
1482 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1485 static int of_spi_register_master(struct spi_master
*master
)
1488 struct device_node
*np
= master
->dev
.of_node
;
1493 nb
= of_gpio_named_count(np
, "cs-gpios");
1494 master
->num_chipselect
= max_t(int, nb
, master
->num_chipselect
);
1496 /* Return error only for an incorrectly formed cs-gpios property */
1497 if (nb
== 0 || nb
== -ENOENT
)
1502 cs
= devm_kzalloc(&master
->dev
,
1503 sizeof(int) * master
->num_chipselect
,
1505 master
->cs_gpios
= cs
;
1507 if (!master
->cs_gpios
)
1510 for (i
= 0; i
< master
->num_chipselect
; i
++)
1513 for (i
= 0; i
< nb
; i
++)
1514 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1519 static int of_spi_register_master(struct spi_master
*master
)
1526 * spi_register_master - register SPI master controller
1527 * @master: initialized master, originally from spi_alloc_master()
1528 * Context: can sleep
1530 * SPI master controllers connect to their drivers using some non-SPI bus,
1531 * such as the platform bus. The final stage of probe() in that code
1532 * includes calling spi_register_master() to hook up to this SPI bus glue.
1534 * SPI controllers use board specific (often SOC specific) bus numbers,
1535 * and board-specific addressing for SPI devices combines those numbers
1536 * with chip select numbers. Since SPI does not directly support dynamic
1537 * device identification, boards need configuration tables telling which
1538 * chip is at which address.
1540 * This must be called from context that can sleep. It returns zero on
1541 * success, else a negative error code (dropping the master's refcount).
1542 * After a successful return, the caller is responsible for calling
1543 * spi_unregister_master().
1545 int spi_register_master(struct spi_master
*master
)
1547 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1548 struct device
*dev
= master
->dev
.parent
;
1549 struct boardinfo
*bi
;
1550 int status
= -ENODEV
;
1556 status
= of_spi_register_master(master
);
1560 /* even if it's just one always-selected device, there must
1561 * be at least one chipselect
1563 if (master
->num_chipselect
== 0)
1566 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1567 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1569 /* convention: dynamically assigned bus IDs count down from the max */
1570 if (master
->bus_num
< 0) {
1571 /* FIXME switch to an IDR based scheme, something like
1572 * I2C now uses, so we can't run out of "dynamic" IDs
1574 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1578 spin_lock_init(&master
->bus_lock_spinlock
);
1579 mutex_init(&master
->bus_lock_mutex
);
1580 master
->bus_lock_flag
= 0;
1581 init_completion(&master
->xfer_completion
);
1582 if (!master
->max_dma_len
)
1583 master
->max_dma_len
= INT_MAX
;
1585 /* register the device, then userspace will see it.
1586 * registration fails if the bus ID is in use.
1588 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1589 status
= device_add(&master
->dev
);
1592 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1593 dynamic
? " (dynamic)" : "");
1595 /* If we're using a queued driver, start the queue */
1596 if (master
->transfer
)
1597 dev_info(dev
, "master is unqueued, this is deprecated\n");
1599 status
= spi_master_initialize_queue(master
);
1601 device_del(&master
->dev
);
1606 mutex_lock(&board_lock
);
1607 list_add_tail(&master
->list
, &spi_master_list
);
1608 list_for_each_entry(bi
, &board_list
, list
)
1609 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1610 mutex_unlock(&board_lock
);
1612 /* Register devices from the device tree and ACPI */
1613 of_register_spi_devices(master
);
1614 acpi_register_spi_devices(master
);
1618 EXPORT_SYMBOL_GPL(spi_register_master
);
1620 static void devm_spi_unregister(struct device
*dev
, void *res
)
1622 spi_unregister_master(*(struct spi_master
**)res
);
1626 * dev_spi_register_master - register managed SPI master controller
1627 * @dev: device managing SPI master
1628 * @master: initialized master, originally from spi_alloc_master()
1629 * Context: can sleep
1631 * Register a SPI device as with spi_register_master() which will
1632 * automatically be unregister
1634 int devm_spi_register_master(struct device
*dev
, struct spi_master
*master
)
1636 struct spi_master
**ptr
;
1639 ptr
= devres_alloc(devm_spi_unregister
, sizeof(*ptr
), GFP_KERNEL
);
1643 ret
= spi_register_master(master
);
1646 devres_add(dev
, ptr
);
1653 EXPORT_SYMBOL_GPL(devm_spi_register_master
);
1655 static int __unregister(struct device
*dev
, void *null
)
1657 spi_unregister_device(to_spi_device(dev
));
1662 * spi_unregister_master - unregister SPI master controller
1663 * @master: the master being unregistered
1664 * Context: can sleep
1666 * This call is used only by SPI master controller drivers, which are the
1667 * only ones directly touching chip registers.
1669 * This must be called from context that can sleep.
1671 void spi_unregister_master(struct spi_master
*master
)
1675 if (master
->queued
) {
1676 if (spi_destroy_queue(master
))
1677 dev_err(&master
->dev
, "queue remove failed\n");
1680 mutex_lock(&board_lock
);
1681 list_del(&master
->list
);
1682 mutex_unlock(&board_lock
);
1684 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1685 device_unregister(&master
->dev
);
1687 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1689 int spi_master_suspend(struct spi_master
*master
)
1693 /* Basically no-ops for non-queued masters */
1694 if (!master
->queued
)
1697 ret
= spi_stop_queue(master
);
1699 dev_err(&master
->dev
, "queue stop failed\n");
1703 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1705 int spi_master_resume(struct spi_master
*master
)
1709 if (!master
->queued
)
1712 ret
= spi_start_queue(master
);
1714 dev_err(&master
->dev
, "queue restart failed\n");
1718 EXPORT_SYMBOL_GPL(spi_master_resume
);
1720 static int __spi_master_match(struct device
*dev
, const void *data
)
1722 struct spi_master
*m
;
1723 const u16
*bus_num
= data
;
1725 m
= container_of(dev
, struct spi_master
, dev
);
1726 return m
->bus_num
== *bus_num
;
1730 * spi_busnum_to_master - look up master associated with bus_num
1731 * @bus_num: the master's bus number
1732 * Context: can sleep
1734 * This call may be used with devices that are registered after
1735 * arch init time. It returns a refcounted pointer to the relevant
1736 * spi_master (which the caller must release), or NULL if there is
1737 * no such master registered.
1739 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1742 struct spi_master
*master
= NULL
;
1744 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1745 __spi_master_match
);
1747 master
= container_of(dev
, struct spi_master
, dev
);
1748 /* reference got in class_find_device */
1751 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1754 /*-------------------------------------------------------------------------*/
1756 /* Core methods for SPI master protocol drivers. Some of the
1757 * other core methods are currently defined as inline functions.
1761 * spi_setup - setup SPI mode and clock rate
1762 * @spi: the device whose settings are being modified
1763 * Context: can sleep, and no requests are queued to the device
1765 * SPI protocol drivers may need to update the transfer mode if the
1766 * device doesn't work with its default. They may likewise need
1767 * to update clock rates or word sizes from initial values. This function
1768 * changes those settings, and must be called from a context that can sleep.
1769 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1770 * effect the next time the device is selected and data is transferred to
1771 * or from it. When this function returns, the spi device is deselected.
1773 * Note that this call will fail if the protocol driver specifies an option
1774 * that the underlying controller or its driver does not support. For
1775 * example, not all hardware supports wire transfers using nine bit words,
1776 * LSB-first wire encoding, or active-high chipselects.
1778 int spi_setup(struct spi_device
*spi
)
1780 unsigned bad_bits
, ugly_bits
;
1783 /* check mode to prevent that DUAL and QUAD set at the same time
1785 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1786 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1788 "setup: can not select dual and quad at the same time\n");
1791 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1793 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1794 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1796 /* help drivers fail *cleanly* when they need options
1797 * that aren't supported with their current master
1799 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1800 ugly_bits
= bad_bits
&
1801 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
);
1804 "setup: ignoring unsupported mode bits %x\n",
1806 spi
->mode
&= ~ugly_bits
;
1807 bad_bits
&= ~ugly_bits
;
1810 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1815 if (!spi
->bits_per_word
)
1816 spi
->bits_per_word
= 8;
1818 if (!spi
->max_speed_hz
)
1819 spi
->max_speed_hz
= spi
->master
->max_speed_hz
;
1821 if (spi
->master
->setup
)
1822 status
= spi
->master
->setup(spi
);
1824 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1825 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1826 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1827 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1828 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1829 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1830 spi
->bits_per_word
, spi
->max_speed_hz
,
1835 EXPORT_SYMBOL_GPL(spi_setup
);
1837 static int __spi_validate(struct spi_device
*spi
, struct spi_message
*message
)
1839 struct spi_master
*master
= spi
->master
;
1840 struct spi_transfer
*xfer
;
1843 if (list_empty(&message
->transfers
))
1846 /* Half-duplex links include original MicroWire, and ones with
1847 * only one data pin like SPI_3WIRE (switches direction) or where
1848 * either MOSI or MISO is missing. They can also be caused by
1849 * software limitations.
1851 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1852 || (spi
->mode
& SPI_3WIRE
)) {
1853 unsigned flags
= master
->flags
;
1855 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1856 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1858 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1860 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1866 * Set transfer bits_per_word and max speed as spi device default if
1867 * it is not set for this transfer.
1868 * Set transfer tx_nbits and rx_nbits as single transfer default
1869 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1871 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1872 message
->frame_length
+= xfer
->len
;
1873 if (!xfer
->bits_per_word
)
1874 xfer
->bits_per_word
= spi
->bits_per_word
;
1876 if (!xfer
->speed_hz
)
1877 xfer
->speed_hz
= spi
->max_speed_hz
;
1879 if (master
->max_speed_hz
&&
1880 xfer
->speed_hz
> master
->max_speed_hz
)
1881 xfer
->speed_hz
= master
->max_speed_hz
;
1883 if (master
->bits_per_word_mask
) {
1884 /* Only 32 bits fit in the mask */
1885 if (xfer
->bits_per_word
> 32)
1887 if (!(master
->bits_per_word_mask
&
1888 BIT(xfer
->bits_per_word
- 1)))
1893 * SPI transfer length should be multiple of SPI word size
1894 * where SPI word size should be power-of-two multiple
1896 if (xfer
->bits_per_word
<= 8)
1898 else if (xfer
->bits_per_word
<= 16)
1903 /* No partial transfers accepted */
1904 if (xfer
->len
% w_size
)
1907 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
1908 xfer
->speed_hz
< master
->min_speed_hz
)
1911 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
1912 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
1913 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
1914 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
1915 /* check transfer tx/rx_nbits:
1916 * 1. check the value matches one of single, dual and quad
1917 * 2. check tx/rx_nbits match the mode in spi_device
1920 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
1921 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
1922 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
1924 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
1925 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
1927 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
1928 !(spi
->mode
& SPI_TX_QUAD
))
1931 /* check transfer rx_nbits */
1933 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
1934 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
1935 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
1937 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
1938 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
1940 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
1941 !(spi
->mode
& SPI_RX_QUAD
))
1946 message
->status
= -EINPROGRESS
;
1951 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1953 struct spi_master
*master
= spi
->master
;
1957 trace_spi_message_submit(message
);
1959 return master
->transfer(spi
, message
);
1963 * spi_async - asynchronous SPI transfer
1964 * @spi: device with which data will be exchanged
1965 * @message: describes the data transfers, including completion callback
1966 * Context: any (irqs may be blocked, etc)
1968 * This call may be used in_irq and other contexts which can't sleep,
1969 * as well as from task contexts which can sleep.
1971 * The completion callback is invoked in a context which can't sleep.
1972 * Before that invocation, the value of message->status is undefined.
1973 * When the callback is issued, message->status holds either zero (to
1974 * indicate complete success) or a negative error code. After that
1975 * callback returns, the driver which issued the transfer request may
1976 * deallocate the associated memory; it's no longer in use by any SPI
1977 * core or controller driver code.
1979 * Note that although all messages to a spi_device are handled in
1980 * FIFO order, messages may go to different devices in other orders.
1981 * Some device might be higher priority, or have various "hard" access
1982 * time requirements, for example.
1984 * On detection of any fault during the transfer, processing of
1985 * the entire message is aborted, and the device is deselected.
1986 * Until returning from the associated message completion callback,
1987 * no other spi_message queued to that device will be processed.
1988 * (This rule applies equally to all the synchronous transfer calls,
1989 * which are wrappers around this core asynchronous primitive.)
1991 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1993 struct spi_master
*master
= spi
->master
;
1995 unsigned long flags
;
1997 ret
= __spi_validate(spi
, message
);
2001 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2003 if (master
->bus_lock_flag
)
2006 ret
= __spi_async(spi
, message
);
2008 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2012 EXPORT_SYMBOL_GPL(spi_async
);
2015 * spi_async_locked - version of spi_async with exclusive bus usage
2016 * @spi: device with which data will be exchanged
2017 * @message: describes the data transfers, including completion callback
2018 * Context: any (irqs may be blocked, etc)
2020 * This call may be used in_irq and other contexts which can't sleep,
2021 * as well as from task contexts which can sleep.
2023 * The completion callback is invoked in a context which can't sleep.
2024 * Before that invocation, the value of message->status is undefined.
2025 * When the callback is issued, message->status holds either zero (to
2026 * indicate complete success) or a negative error code. After that
2027 * callback returns, the driver which issued the transfer request may
2028 * deallocate the associated memory; it's no longer in use by any SPI
2029 * core or controller driver code.
2031 * Note that although all messages to a spi_device are handled in
2032 * FIFO order, messages may go to different devices in other orders.
2033 * Some device might be higher priority, or have various "hard" access
2034 * time requirements, for example.
2036 * On detection of any fault during the transfer, processing of
2037 * the entire message is aborted, and the device is deselected.
2038 * Until returning from the associated message completion callback,
2039 * no other spi_message queued to that device will be processed.
2040 * (This rule applies equally to all the synchronous transfer calls,
2041 * which are wrappers around this core asynchronous primitive.)
2043 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
2045 struct spi_master
*master
= spi
->master
;
2047 unsigned long flags
;
2049 ret
= __spi_validate(spi
, message
);
2053 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2055 ret
= __spi_async(spi
, message
);
2057 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2062 EXPORT_SYMBOL_GPL(spi_async_locked
);
2065 /*-------------------------------------------------------------------------*/
2067 /* Utility methods for SPI master protocol drivers, layered on
2068 * top of the core. Some other utility methods are defined as
2072 static void spi_complete(void *arg
)
2077 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
2080 DECLARE_COMPLETION_ONSTACK(done
);
2082 struct spi_master
*master
= spi
->master
;
2084 message
->complete
= spi_complete
;
2085 message
->context
= &done
;
2088 mutex_lock(&master
->bus_lock_mutex
);
2090 status
= spi_async_locked(spi
, message
);
2093 mutex_unlock(&master
->bus_lock_mutex
);
2096 wait_for_completion(&done
);
2097 status
= message
->status
;
2099 message
->context
= NULL
;
2104 * spi_sync - blocking/synchronous SPI data transfers
2105 * @spi: device with which data will be exchanged
2106 * @message: describes the data transfers
2107 * Context: can sleep
2109 * This call may only be used from a context that may sleep. The sleep
2110 * is non-interruptible, and has no timeout. Low-overhead controller
2111 * drivers may DMA directly into and out of the message buffers.
2113 * Note that the SPI device's chip select is active during the message,
2114 * and then is normally disabled between messages. Drivers for some
2115 * frequently-used devices may want to minimize costs of selecting a chip,
2116 * by leaving it selected in anticipation that the next message will go
2117 * to the same chip. (That may increase power usage.)
2119 * Also, the caller is guaranteeing that the memory associated with the
2120 * message will not be freed before this call returns.
2122 * It returns zero on success, else a negative error code.
2124 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
2126 return __spi_sync(spi
, message
, 0);
2128 EXPORT_SYMBOL_GPL(spi_sync
);
2131 * spi_sync_locked - version of spi_sync with exclusive bus usage
2132 * @spi: device with which data will be exchanged
2133 * @message: describes the data transfers
2134 * Context: can sleep
2136 * This call may only be used from a context that may sleep. The sleep
2137 * is non-interruptible, and has no timeout. Low-overhead controller
2138 * drivers may DMA directly into and out of the message buffers.
2140 * This call should be used by drivers that require exclusive access to the
2141 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2142 * be released by a spi_bus_unlock call when the exclusive access is over.
2144 * It returns zero on success, else a negative error code.
2146 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
2148 return __spi_sync(spi
, message
, 1);
2150 EXPORT_SYMBOL_GPL(spi_sync_locked
);
2153 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2154 * @master: SPI bus master that should be locked for exclusive bus access
2155 * Context: can sleep
2157 * This call may only be used from a context that may sleep. The sleep
2158 * is non-interruptible, and has no timeout.
2160 * This call should be used by drivers that require exclusive access to the
2161 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2162 * exclusive access is over. Data transfer must be done by spi_sync_locked
2163 * and spi_async_locked calls when the SPI bus lock is held.
2165 * It returns zero on success, else a negative error code.
2167 int spi_bus_lock(struct spi_master
*master
)
2169 unsigned long flags
;
2171 mutex_lock(&master
->bus_lock_mutex
);
2173 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2174 master
->bus_lock_flag
= 1;
2175 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2177 /* mutex remains locked until spi_bus_unlock is called */
2181 EXPORT_SYMBOL_GPL(spi_bus_lock
);
2184 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2185 * @master: SPI bus master that was locked for exclusive bus access
2186 * Context: can sleep
2188 * This call may only be used from a context that may sleep. The sleep
2189 * is non-interruptible, and has no timeout.
2191 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2194 * It returns zero on success, else a negative error code.
2196 int spi_bus_unlock(struct spi_master
*master
)
2198 master
->bus_lock_flag
= 0;
2200 mutex_unlock(&master
->bus_lock_mutex
);
2204 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
2206 /* portable code must never pass more than 32 bytes */
2207 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2212 * spi_write_then_read - SPI synchronous write followed by read
2213 * @spi: device with which data will be exchanged
2214 * @txbuf: data to be written (need not be dma-safe)
2215 * @n_tx: size of txbuf, in bytes
2216 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2217 * @n_rx: size of rxbuf, in bytes
2218 * Context: can sleep
2220 * This performs a half duplex MicroWire style transaction with the
2221 * device, sending txbuf and then reading rxbuf. The return value
2222 * is zero for success, else a negative errno status code.
2223 * This call may only be used from a context that may sleep.
2225 * Parameters to this routine are always copied using a small buffer;
2226 * portable code should never use this for more than 32 bytes.
2227 * Performance-sensitive or bulk transfer code should instead use
2228 * spi_{async,sync}() calls with dma-safe buffers.
2230 int spi_write_then_read(struct spi_device
*spi
,
2231 const void *txbuf
, unsigned n_tx
,
2232 void *rxbuf
, unsigned n_rx
)
2234 static DEFINE_MUTEX(lock
);
2237 struct spi_message message
;
2238 struct spi_transfer x
[2];
2241 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2242 * copying here, (as a pure convenience thing), but we can
2243 * keep heap costs out of the hot path unless someone else is
2244 * using the pre-allocated buffer or the transfer is too large.
2246 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
2247 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
2248 GFP_KERNEL
| GFP_DMA
);
2255 spi_message_init(&message
);
2256 memset(x
, 0, sizeof(x
));
2259 spi_message_add_tail(&x
[0], &message
);
2263 spi_message_add_tail(&x
[1], &message
);
2266 memcpy(local_buf
, txbuf
, n_tx
);
2267 x
[0].tx_buf
= local_buf
;
2268 x
[1].rx_buf
= local_buf
+ n_tx
;
2271 status
= spi_sync(spi
, &message
);
2273 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
2275 if (x
[0].tx_buf
== buf
)
2276 mutex_unlock(&lock
);
2282 EXPORT_SYMBOL_GPL(spi_write_then_read
);
2284 /*-------------------------------------------------------------------------*/
2286 static int __init
spi_init(void)
2290 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
2296 status
= bus_register(&spi_bus_type
);
2300 status
= class_register(&spi_master_class
);
2306 bus_unregister(&spi_bus_type
);
2314 /* board_info is normally registered in arch_initcall(),
2315 * but even essential drivers wait till later
2317 * REVISIT only boardinfo really needs static linking. the rest (device and
2318 * driver registration) _could_ be dynamically linked (modular) ... costs
2319 * include needing to have boardinfo data structures be much more public.
2321 postcore_initcall(spi_init
);