2 * Driver for the ADC present in the Atmel AT91 evaluation boards.
4 * Copyright 2011 Free Electrons
6 * Licensed under the GPLv2 or later.
9 #include <linux/bitmap.h>
10 #include <linux/bitops.h>
11 #include <linux/clk.h>
12 #include <linux/err.h>
14 #include <linux/interrupt.h>
15 #include <linux/jiffies.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
19 #include <linux/of_device.h>
20 #include <linux/platform_device.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/wait.h>
25 #include <linux/platform_data/at91_adc.h>
27 #include <linux/iio/iio.h>
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/trigger.h>
30 #include <linux/iio/trigger_consumer.h>
31 #include <linux/iio/triggered_buffer.h>
33 #include <mach/at91_adc.h>
35 #define AT91_ADC_CHAN(st, ch) \
36 (st->registers->channel_base + (ch * 4))
37 #define at91_adc_readl(st, reg) \
38 (readl_relaxed(st->reg_base + reg))
39 #define at91_adc_writel(st, reg, val) \
40 (writel_relaxed(val, st->reg_base + reg))
42 struct at91_adc_state
{
45 unsigned long channels_mask
;
53 void __iomem
*reg_base
;
54 struct at91_adc_reg_desc
*registers
;
56 struct iio_trigger
**trig
;
57 struct at91_adc_trigger
*trigger_list
;
61 wait_queue_head_t wq_data_avail
;
64 static irqreturn_t
at91_adc_trigger_handler(int irq
, void *p
)
66 struct iio_poll_func
*pf
= p
;
67 struct iio_dev
*idev
= pf
->indio_dev
;
68 struct at91_adc_state
*st
= iio_priv(idev
);
69 struct iio_buffer
*buffer
= idev
->buffer
;
72 for (i
= 0; i
< idev
->masklength
; i
++) {
73 if (!test_bit(i
, idev
->active_scan_mask
))
75 st
->buffer
[j
] = at91_adc_readl(st
, AT91_ADC_CHAN(st
, i
));
79 if (idev
->scan_timestamp
) {
80 s64
*timestamp
= (s64
*)((u8
*)st
->buffer
+
81 ALIGN(j
, sizeof(s64
)));
82 *timestamp
= pf
->timestamp
;
85 buffer
->access
->store_to(buffer
, (u8
*)st
->buffer
, pf
->timestamp
);
87 iio_trigger_notify_done(idev
->trig
);
88 st
->irq_enabled
= true;
90 /* Needed to ACK the DRDY interruption */
91 at91_adc_readl(st
, AT91_ADC_LCDR
);
98 static irqreturn_t
at91_adc_eoc_trigger(int irq
, void *private)
100 struct iio_dev
*idev
= private;
101 struct at91_adc_state
*st
= iio_priv(idev
);
102 u32 status
= at91_adc_readl(st
, st
->registers
->status_register
);
104 if (!(status
& st
->registers
->drdy_mask
))
107 if (iio_buffer_enabled(idev
)) {
108 disable_irq_nosync(irq
);
109 st
->irq_enabled
= false;
110 iio_trigger_poll(idev
->trig
, iio_get_time_ns());
112 st
->last_value
= at91_adc_readl(st
, AT91_ADC_LCDR
);
114 wake_up_interruptible(&st
->wq_data_avail
);
120 static int at91_adc_channel_init(struct iio_dev
*idev
)
122 struct at91_adc_state
*st
= iio_priv(idev
);
123 struct iio_chan_spec
*chan_array
, *timestamp
;
126 idev
->num_channels
= bitmap_weight(&st
->channels_mask
,
127 st
->num_channels
) + 1;
129 chan_array
= devm_kzalloc(&idev
->dev
,
130 ((idev
->num_channels
+ 1) *
131 sizeof(struct iio_chan_spec
)),
137 for_each_set_bit(bit
, &st
->channels_mask
, st
->num_channels
) {
138 struct iio_chan_spec
*chan
= chan_array
+ idx
;
140 chan
->type
= IIO_VOLTAGE
;
143 chan
->scan_index
= idx
;
144 chan
->scan_type
.sign
= 'u';
145 chan
->scan_type
.realbits
= 10;
146 chan
->scan_type
.storagebits
= 16;
147 chan
->info_mask
= IIO_CHAN_INFO_SCALE_SHARED_BIT
|
148 IIO_CHAN_INFO_RAW_SEPARATE_BIT
;
151 timestamp
= chan_array
+ idx
;
153 timestamp
->type
= IIO_TIMESTAMP
;
154 timestamp
->channel
= -1;
155 timestamp
->scan_index
= idx
;
156 timestamp
->scan_type
.sign
= 's';
157 timestamp
->scan_type
.realbits
= 64;
158 timestamp
->scan_type
.storagebits
= 64;
160 idev
->channels
= chan_array
;
161 return idev
->num_channels
;
164 static u8
at91_adc_get_trigger_value_by_name(struct iio_dev
*idev
,
165 struct at91_adc_trigger
*triggers
,
166 const char *trigger_name
)
168 struct at91_adc_state
*st
= iio_priv(idev
);
172 for (i
= 0; i
< st
->trigger_number
; i
++) {
173 char *name
= kasprintf(GFP_KERNEL
,
181 if (strcmp(trigger_name
, name
) == 0) {
182 value
= triggers
[i
].value
;
193 static int at91_adc_configure_trigger(struct iio_trigger
*trig
, bool state
)
195 struct iio_dev
*idev
= trig
->private_data
;
196 struct at91_adc_state
*st
= iio_priv(idev
);
197 struct iio_buffer
*buffer
= idev
->buffer
;
198 struct at91_adc_reg_desc
*reg
= st
->registers
;
199 u32 status
= at91_adc_readl(st
, reg
->trigger_register
);
203 value
= at91_adc_get_trigger_value_by_name(idev
,
210 st
->buffer
= kmalloc(idev
->scan_bytes
, GFP_KERNEL
);
211 if (st
->buffer
== NULL
)
214 at91_adc_writel(st
, reg
->trigger_register
,
217 for_each_set_bit(bit
, buffer
->scan_mask
,
219 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
220 at91_adc_writel(st
, AT91_ADC_CHER
,
221 AT91_ADC_CH(chan
->channel
));
224 at91_adc_writel(st
, AT91_ADC_IER
, reg
->drdy_mask
);
227 at91_adc_writel(st
, AT91_ADC_IDR
, reg
->drdy_mask
);
229 at91_adc_writel(st
, reg
->trigger_register
,
232 for_each_set_bit(bit
, buffer
->scan_mask
,
234 struct iio_chan_spec
const *chan
= idev
->channels
+ bit
;
235 at91_adc_writel(st
, AT91_ADC_CHDR
,
236 AT91_ADC_CH(chan
->channel
));
244 static const struct iio_trigger_ops at91_adc_trigger_ops
= {
245 .owner
= THIS_MODULE
,
246 .set_trigger_state
= &at91_adc_configure_trigger
,
249 static struct iio_trigger
*at91_adc_allocate_trigger(struct iio_dev
*idev
,
250 struct at91_adc_trigger
*trigger
)
252 struct iio_trigger
*trig
;
255 trig
= iio_trigger_alloc("%s-dev%d-%s", idev
->name
,
256 idev
->id
, trigger
->name
);
260 trig
->dev
.parent
= idev
->dev
.parent
;
261 trig
->private_data
= idev
;
262 trig
->ops
= &at91_adc_trigger_ops
;
264 ret
= iio_trigger_register(trig
);
271 static int at91_adc_trigger_init(struct iio_dev
*idev
)
273 struct at91_adc_state
*st
= iio_priv(idev
);
276 st
->trig
= devm_kzalloc(&idev
->dev
,
277 st
->trigger_number
* sizeof(st
->trig
),
280 if (st
->trig
== NULL
) {
285 for (i
= 0; i
< st
->trigger_number
; i
++) {
286 if (st
->trigger_list
[i
].is_external
&& !(st
->use_external
))
289 st
->trig
[i
] = at91_adc_allocate_trigger(idev
,
290 st
->trigger_list
+ i
);
291 if (st
->trig
[i
] == NULL
) {
293 "Could not allocate trigger %d\n", i
);
302 for (i
--; i
>= 0; i
--) {
303 iio_trigger_unregister(st
->trig
[i
]);
304 iio_trigger_free(st
->trig
[i
]);
310 static void at91_adc_trigger_remove(struct iio_dev
*idev
)
312 struct at91_adc_state
*st
= iio_priv(idev
);
315 for (i
= 0; i
< st
->trigger_number
; i
++) {
316 iio_trigger_unregister(st
->trig
[i
]);
317 iio_trigger_free(st
->trig
[i
]);
321 static int at91_adc_buffer_init(struct iio_dev
*idev
)
323 return iio_triggered_buffer_setup(idev
, &iio_pollfunc_store_time
,
324 &at91_adc_trigger_handler
, NULL
);
327 static void at91_adc_buffer_remove(struct iio_dev
*idev
)
329 iio_triggered_buffer_cleanup(idev
);
332 static int at91_adc_read_raw(struct iio_dev
*idev
,
333 struct iio_chan_spec
const *chan
,
334 int *val
, int *val2
, long mask
)
336 struct at91_adc_state
*st
= iio_priv(idev
);
340 case IIO_CHAN_INFO_RAW
:
341 mutex_lock(&st
->lock
);
343 at91_adc_writel(st
, AT91_ADC_CHER
,
344 AT91_ADC_CH(chan
->channel
));
345 at91_adc_writel(st
, AT91_ADC_IER
, st
->registers
->drdy_mask
);
346 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_START
);
348 ret
= wait_event_interruptible_timeout(st
->wq_data_avail
,
350 msecs_to_jiffies(1000));
354 mutex_unlock(&st
->lock
);
358 *val
= st
->last_value
;
360 at91_adc_writel(st
, AT91_ADC_CHDR
,
361 AT91_ADC_CH(chan
->channel
));
362 at91_adc_writel(st
, AT91_ADC_IDR
, st
->registers
->drdy_mask
);
366 mutex_unlock(&st
->lock
);
369 case IIO_CHAN_INFO_SCALE
:
370 *val
= (st
->vref_mv
* 1000) >> chan
->scan_type
.realbits
;
372 return IIO_VAL_INT_PLUS_MICRO
;
379 static int at91_adc_probe_dt(struct at91_adc_state
*st
,
380 struct platform_device
*pdev
)
382 struct iio_dev
*idev
= iio_priv_to_dev(st
);
383 struct device_node
*node
= pdev
->dev
.of_node
;
384 struct device_node
*trig_node
;
391 st
->use_external
= of_property_read_bool(node
, "atmel,adc-use-external-triggers");
393 if (of_property_read_u32(node
, "atmel,adc-channels-used", &prop
)) {
394 dev_err(&idev
->dev
, "Missing adc-channels-used property in the DT.\n");
398 st
->channels_mask
= prop
;
400 if (of_property_read_u32(node
, "atmel,adc-num-channels", &prop
)) {
401 dev_err(&idev
->dev
, "Missing adc-num-channels property in the DT.\n");
405 st
->num_channels
= prop
;
407 if (of_property_read_u32(node
, "atmel,adc-startup-time", &prop
)) {
408 dev_err(&idev
->dev
, "Missing adc-startup-time property in the DT.\n");
412 st
->startup_time
= prop
;
415 if (of_property_read_u32(node
, "atmel,adc-vref", &prop
)) {
416 dev_err(&idev
->dev
, "Missing adc-vref property in the DT.\n");
422 st
->registers
= devm_kzalloc(&idev
->dev
,
423 sizeof(struct at91_adc_reg_desc
),
425 if (!st
->registers
) {
426 dev_err(&idev
->dev
, "Could not allocate register memory.\n");
431 if (of_property_read_u32(node
, "atmel,adc-channel-base", &prop
)) {
432 dev_err(&idev
->dev
, "Missing adc-channel-base property in the DT.\n");
436 st
->registers
->channel_base
= prop
;
438 if (of_property_read_u32(node
, "atmel,adc-drdy-mask", &prop
)) {
439 dev_err(&idev
->dev
, "Missing adc-drdy-mask property in the DT.\n");
443 st
->registers
->drdy_mask
= prop
;
445 if (of_property_read_u32(node
, "atmel,adc-status-register", &prop
)) {
446 dev_err(&idev
->dev
, "Missing adc-status-register property in the DT.\n");
450 st
->registers
->status_register
= prop
;
452 if (of_property_read_u32(node
, "atmel,adc-trigger-register", &prop
)) {
453 dev_err(&idev
->dev
, "Missing adc-trigger-register property in the DT.\n");
457 st
->registers
->trigger_register
= prop
;
459 st
->trigger_number
= of_get_child_count(node
);
460 st
->trigger_list
= devm_kzalloc(&idev
->dev
, st
->trigger_number
*
461 sizeof(struct at91_adc_trigger
),
463 if (!st
->trigger_list
) {
464 dev_err(&idev
->dev
, "Could not allocate trigger list memory.\n");
469 for_each_child_of_node(node
, trig_node
) {
470 struct at91_adc_trigger
*trig
= st
->trigger_list
+ i
;
473 if (of_property_read_string(trig_node
, "trigger-name", &name
)) {
474 dev_err(&idev
->dev
, "Missing trigger-name property in the DT.\n");
480 if (of_property_read_u32(trig_node
, "trigger-value", &prop
)) {
481 dev_err(&idev
->dev
, "Missing trigger-value property in the DT.\n");
486 trig
->is_external
= of_property_read_bool(trig_node
, "trigger-external");
496 static int at91_adc_probe_pdata(struct at91_adc_state
*st
,
497 struct platform_device
*pdev
)
499 struct at91_adc_data
*pdata
= pdev
->dev
.platform_data
;
504 st
->use_external
= pdata
->use_external_triggers
;
505 st
->vref_mv
= pdata
->vref
;
506 st
->channels_mask
= pdata
->channels_used
;
507 st
->num_channels
= pdata
->num_channels
;
508 st
->startup_time
= pdata
->startup_time
;
509 st
->trigger_number
= pdata
->trigger_number
;
510 st
->trigger_list
= pdata
->trigger_list
;
511 st
->registers
= pdata
->registers
;
516 static const struct iio_info at91_adc_info
= {
517 .driver_module
= THIS_MODULE
,
518 .read_raw
= &at91_adc_read_raw
,
521 static int __devinit
at91_adc_probe(struct platform_device
*pdev
)
523 unsigned int prsc
, mstrclk
, ticks
, adc_clk
;
525 struct iio_dev
*idev
;
526 struct at91_adc_state
*st
;
527 struct resource
*res
;
529 idev
= iio_device_alloc(sizeof(struct at91_adc_state
));
537 if (pdev
->dev
.of_node
)
538 ret
= at91_adc_probe_dt(st
, pdev
);
540 ret
= at91_adc_probe_pdata(st
, pdev
);
543 dev_err(&pdev
->dev
, "No platform data available.\n");
545 goto error_free_device
;
548 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
550 dev_err(&pdev
->dev
, "No resource defined\n");
555 platform_set_drvdata(pdev
, idev
);
557 idev
->dev
.parent
= &pdev
->dev
;
558 idev
->name
= dev_name(&pdev
->dev
);
559 idev
->modes
= INDIO_DIRECT_MODE
;
560 idev
->info
= &at91_adc_info
;
562 st
->irq
= platform_get_irq(pdev
, 0);
564 dev_err(&pdev
->dev
, "No IRQ ID is designated\n");
566 goto error_free_device
;
569 if (!request_mem_region(res
->start
, resource_size(res
),
570 "AT91 adc registers")) {
571 dev_err(&pdev
->dev
, "Resources are unavailable.\n");
573 goto error_free_device
;
576 st
->reg_base
= ioremap(res
->start
, resource_size(res
));
578 dev_err(&pdev
->dev
, "Failed to map registers.\n");
580 goto error_release_mem
;
584 * Disable all IRQs before setting up the handler
586 at91_adc_writel(st
, AT91_ADC_CR
, AT91_ADC_SWRST
);
587 at91_adc_writel(st
, AT91_ADC_IDR
, 0xFFFFFFFF);
588 ret
= request_irq(st
->irq
,
589 at91_adc_eoc_trigger
,
591 pdev
->dev
.driver
->name
,
594 dev_err(&pdev
->dev
, "Failed to allocate IRQ.\n");
595 goto error_unmap_reg
;
598 st
->clk
= clk_get(&pdev
->dev
, "adc_clk");
599 if (IS_ERR(st
->clk
)) {
600 dev_err(&pdev
->dev
, "Failed to get the clock.\n");
601 ret
= PTR_ERR(st
->clk
);
605 ret
= clk_prepare(st
->clk
);
607 dev_err(&pdev
->dev
, "Could not prepare the clock.\n");
611 ret
= clk_enable(st
->clk
);
613 dev_err(&pdev
->dev
, "Could not enable the clock.\n");
614 goto error_unprepare_clk
;
617 st
->adc_clk
= clk_get(&pdev
->dev
, "adc_op_clk");
618 if (IS_ERR(st
->adc_clk
)) {
619 dev_err(&pdev
->dev
, "Failed to get the ADC clock.\n");
620 ret
= PTR_ERR(st
->clk
);
621 goto error_disable_clk
;
624 ret
= clk_prepare(st
->adc_clk
);
626 dev_err(&pdev
->dev
, "Could not prepare the ADC clock.\n");
627 goto error_free_adc_clk
;
630 ret
= clk_enable(st
->adc_clk
);
632 dev_err(&pdev
->dev
, "Could not enable the ADC clock.\n");
633 goto error_unprepare_adc_clk
;
637 * Prescaler rate computation using the formula from the Atmel's
638 * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being
639 * specified by the electrical characteristics of the board.
641 mstrclk
= clk_get_rate(st
->clk
);
642 adc_clk
= clk_get_rate(st
->adc_clk
);
643 prsc
= (mstrclk
/ (2 * adc_clk
)) - 1;
645 if (!st
->startup_time
) {
646 dev_err(&pdev
->dev
, "No startup time available.\n");
648 goto error_disable_adc_clk
;
652 * Number of ticks needed to cover the startup time of the ADC as
653 * defined in the electrical characteristics of the board, divided by 8.
654 * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock
656 ticks
= round_up((st
->startup_time
* adc_clk
/
657 1000000) - 1, 8) / 8;
658 at91_adc_writel(st
, AT91_ADC_MR
,
659 (AT91_ADC_PRESCAL_(prsc
) & AT91_ADC_PRESCAL
) |
660 (AT91_ADC_STARTUP_(ticks
) & AT91_ADC_STARTUP
));
662 /* Setup the ADC channels available on the board */
663 ret
= at91_adc_channel_init(idev
);
665 dev_err(&pdev
->dev
, "Couldn't initialize the channels.\n");
666 goto error_disable_adc_clk
;
669 init_waitqueue_head(&st
->wq_data_avail
);
670 mutex_init(&st
->lock
);
672 ret
= at91_adc_buffer_init(idev
);
674 dev_err(&pdev
->dev
, "Couldn't initialize the buffer.\n");
675 goto error_disable_adc_clk
;
678 ret
= at91_adc_trigger_init(idev
);
680 dev_err(&pdev
->dev
, "Couldn't setup the triggers.\n");
681 goto error_unregister_buffer
;
684 ret
= iio_device_register(idev
);
686 dev_err(&pdev
->dev
, "Couldn't register the device.\n");
687 goto error_remove_triggers
;
692 error_remove_triggers
:
693 at91_adc_trigger_remove(idev
);
694 error_unregister_buffer
:
695 at91_adc_buffer_remove(idev
);
696 error_disable_adc_clk
:
697 clk_disable(st
->adc_clk
);
698 error_unprepare_adc_clk
:
699 clk_unprepare(st
->adc_clk
);
701 clk_put(st
->adc_clk
);
703 clk_disable(st
->clk
);
705 clk_unprepare(st
->clk
);
709 free_irq(st
->irq
, idev
);
711 iounmap(st
->reg_base
);
713 release_mem_region(res
->start
, resource_size(res
));
715 iio_device_free(idev
);
720 static int __devexit
at91_adc_remove(struct platform_device
*pdev
)
722 struct iio_dev
*idev
= platform_get_drvdata(pdev
);
723 struct resource
*res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
724 struct at91_adc_state
*st
= iio_priv(idev
);
726 iio_device_unregister(idev
);
727 at91_adc_trigger_remove(idev
);
728 at91_adc_buffer_remove(idev
);
729 clk_disable_unprepare(st
->adc_clk
);
730 clk_put(st
->adc_clk
);
731 clk_disable(st
->clk
);
732 clk_unprepare(st
->clk
);
734 free_irq(st
->irq
, idev
);
735 iounmap(st
->reg_base
);
736 release_mem_region(res
->start
, resource_size(res
));
737 iio_device_free(idev
);
742 static const struct of_device_id at91_adc_dt_ids
[] = {
743 { .compatible
= "atmel,at91sam9260-adc" },
746 MODULE_DEVICE_TABLE(of
, at91_adc_dt_ids
);
748 static struct platform_driver at91_adc_driver
= {
749 .probe
= at91_adc_probe
,
750 .remove
= __devexit_p(at91_adc_remove
),
753 .of_match_table
= of_match_ptr(at91_adc_dt_ids
),
757 module_platform_driver(at91_adc_driver
);
759 MODULE_LICENSE("GPL");
760 MODULE_DESCRIPTION("Atmel AT91 ADC Driver");
761 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");