2 * GPIO driver for the ACCES 104-IDI-48 family
3 * Copyright (C) 2015 William Breathitt Gray
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 #include <linux/bitops.h>
15 #include <linux/device.h>
16 #include <linux/errno.h>
17 #include <linux/gpio/driver.h>
19 #include <linux/ioport.h>
20 #include <linux/interrupt.h>
21 #include <linux/irqdesc.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/platform_device.h>
26 #include <linux/spinlock.h>
28 static unsigned idi_48_base
;
29 module_param(idi_48_base
, uint
, 0);
30 MODULE_PARM_DESC(idi_48_base
, "ACCES 104-IDI-48 base address");
31 static unsigned idi_48_irq
;
32 module_param(idi_48_irq
, uint
, 0);
33 MODULE_PARM_DESC(idi_48_irq
, "ACCES 104-IDI-48 interrupt line number");
36 * struct idi_48_gpio - GPIO device private data structure
37 * @chip: instance of the gpio_chip
38 * @lock: synchronization lock to prevent I/O race conditions
39 * @ack_lock: synchronization lock to prevent IRQ handler race conditions
40 * @irq_mask: input bits affected by interrupts
41 * @base: base port address of the GPIO device
42 * @extent: extent of port address region of the GPIO device
43 * @irq: Interrupt line number
44 * @cos_enb: Change-Of-State IRQ enable boundaries mask
47 struct gpio_chip chip
;
50 unsigned char irq_mask
[6];
54 unsigned char cos_enb
;
57 static int idi_48_gpio_get_direction(struct gpio_chip
*chip
, unsigned offset
)
62 static int idi_48_gpio_direction_input(struct gpio_chip
*chip
, unsigned offset
)
67 static int idi_48_gpio_get(struct gpio_chip
*chip
, unsigned offset
)
69 struct idi_48_gpio
*const idi48gpio
= gpiochip_get_data(chip
);
71 const unsigned register_offset
[6] = { 0, 1, 2, 4, 5, 6 };
75 for (i
= 0; i
< 48; i
+= 8)
77 base_offset
= register_offset
[i
/ 8];
78 mask
= BIT(offset
- i
);
80 return !!(inb(idi48gpio
->base
+ base_offset
) & mask
);
83 /* The following line should never execute since offset < 48 */
87 static void idi_48_irq_ack(struct irq_data
*data
)
91 static void idi_48_irq_mask(struct irq_data
*data
)
93 struct gpio_chip
*chip
= irq_data_get_irq_chip_data(data
);
94 struct idi_48_gpio
*const idi48gpio
= gpiochip_get_data(chip
);
95 const unsigned offset
= irqd_to_hwirq(data
);
101 for (i
= 0; i
< 48; i
+= 8)
102 if (offset
< i
+ 8) {
103 mask
= BIT(offset
- i
);
106 idi48gpio
->irq_mask
[boundary
] &= ~mask
;
108 if (!idi48gpio
->irq_mask
[boundary
]) {
109 idi48gpio
->cos_enb
&= ~BIT(boundary
);
111 spin_lock_irqsave(&idi48gpio
->lock
, flags
);
113 outb(idi48gpio
->cos_enb
, idi48gpio
->base
+ 7);
115 spin_unlock_irqrestore(&idi48gpio
->lock
, flags
);
122 static void idi_48_irq_unmask(struct irq_data
*data
)
124 struct gpio_chip
*chip
= irq_data_get_irq_chip_data(data
);
125 struct idi_48_gpio
*const idi48gpio
= gpiochip_get_data(chip
);
126 const unsigned offset
= irqd_to_hwirq(data
);
130 unsigned prev_irq_mask
;
133 for (i
= 0; i
< 48; i
+= 8)
134 if (offset
< i
+ 8) {
135 mask
= BIT(offset
- i
);
137 prev_irq_mask
= idi48gpio
->irq_mask
[boundary
];
139 idi48gpio
->irq_mask
[boundary
] |= mask
;
141 if (!prev_irq_mask
) {
142 idi48gpio
->cos_enb
|= BIT(boundary
);
144 spin_lock_irqsave(&idi48gpio
->lock
, flags
);
146 outb(idi48gpio
->cos_enb
, idi48gpio
->base
+ 7);
148 spin_unlock_irqrestore(&idi48gpio
->lock
, flags
);
155 static int idi_48_irq_set_type(struct irq_data
*data
, unsigned flow_type
)
157 /* The only valid irq types are none and both-edges */
158 if (flow_type
!= IRQ_TYPE_NONE
&&
159 (flow_type
& IRQ_TYPE_EDGE_BOTH
) != IRQ_TYPE_EDGE_BOTH
)
165 static struct irq_chip idi_48_irqchip
= {
166 .name
= "104-idi-48",
167 .irq_ack
= idi_48_irq_ack
,
168 .irq_mask
= idi_48_irq_mask
,
169 .irq_unmask
= idi_48_irq_unmask
,
170 .irq_set_type
= idi_48_irq_set_type
173 static irqreturn_t
idi_48_irq_handler(int irq
, void *dev_id
)
175 struct idi_48_gpio
*const idi48gpio
= dev_id
;
176 unsigned long cos_status
;
177 unsigned long boundary
;
178 unsigned long irq_mask
;
179 unsigned long bit_num
;
181 struct gpio_chip
*const chip
= &idi48gpio
->chip
;
183 spin_lock(&idi48gpio
->ack_lock
);
185 spin_lock(&idi48gpio
->lock
);
187 cos_status
= inb(idi48gpio
->base
+ 7);
189 spin_unlock(&idi48gpio
->lock
);
191 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
192 if (cos_status
& BIT(6)) {
193 spin_unlock(&idi48gpio
->ack_lock
);
197 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
200 for_each_set_bit(boundary
, &cos_status
, 6) {
201 irq_mask
= idi48gpio
->irq_mask
[boundary
];
203 for_each_set_bit(bit_num
, &irq_mask
, 8) {
204 gpio
= bit_num
+ boundary
* 8;
206 generic_handle_irq(irq_find_mapping(chip
->irqdomain
,
211 spin_unlock(&idi48gpio
->ack_lock
);
216 static int __init
idi_48_probe(struct platform_device
*pdev
)
218 struct device
*dev
= &pdev
->dev
;
219 struct idi_48_gpio
*idi48gpio
;
220 const unsigned base
= idi_48_base
;
221 const unsigned extent
= 8;
222 const char *const name
= dev_name(dev
);
224 const unsigned irq
= idi_48_irq
;
226 idi48gpio
= devm_kzalloc(dev
, sizeof(*idi48gpio
), GFP_KERNEL
);
230 if (!request_region(base
, extent
, name
)) {
231 dev_err(dev
, "Unable to lock %s port addresses (0x%X-0x%X)\n",
232 name
, base
, base
+ extent
);
234 goto err_lock_io_port
;
237 idi48gpio
->chip
.label
= name
;
238 idi48gpio
->chip
.parent
= dev
;
239 idi48gpio
->chip
.owner
= THIS_MODULE
;
240 idi48gpio
->chip
.base
= -1;
241 idi48gpio
->chip
.ngpio
= 48;
242 idi48gpio
->chip
.get_direction
= idi_48_gpio_get_direction
;
243 idi48gpio
->chip
.direction_input
= idi_48_gpio_direction_input
;
244 idi48gpio
->chip
.get
= idi_48_gpio_get
;
245 idi48gpio
->base
= base
;
246 idi48gpio
->extent
= extent
;
247 idi48gpio
->irq
= irq
;
249 spin_lock_init(&idi48gpio
->lock
);
251 dev_set_drvdata(dev
, idi48gpio
);
253 err
= gpiochip_add_data(&idi48gpio
->chip
, idi48gpio
);
255 dev_err(dev
, "GPIO registering failed (%d)\n", err
);
256 goto err_gpio_register
;
259 /* Disable IRQ by default */
263 err
= gpiochip_irqchip_add(&idi48gpio
->chip
, &idi_48_irqchip
, 0,
264 handle_edge_irq
, IRQ_TYPE_NONE
);
266 dev_err(dev
, "Could not add irqchip (%d)\n", err
);
267 goto err_gpiochip_irqchip_add
;
270 err
= request_irq(irq
, idi_48_irq_handler
, 0, name
, idi48gpio
);
272 dev_err(dev
, "IRQ handler registering failed (%d)\n", err
);
273 goto err_request_irq
;
279 err_gpiochip_irqchip_add
:
280 gpiochip_remove(&idi48gpio
->chip
);
282 release_region(base
, extent
);
287 static int idi_48_remove(struct platform_device
*pdev
)
289 struct idi_48_gpio
*const idi48gpio
= platform_get_drvdata(pdev
);
291 free_irq(idi48gpio
->irq
, idi48gpio
);
292 gpiochip_remove(&idi48gpio
->chip
);
293 release_region(idi48gpio
->base
, idi48gpio
->extent
);
298 static struct platform_device
*idi_48_device
;
300 static struct platform_driver idi_48_driver
= {
304 .remove
= idi_48_remove
307 static void __exit
idi_48_exit(void)
309 platform_device_unregister(idi_48_device
);
310 platform_driver_unregister(&idi_48_driver
);
313 static int __init
idi_48_init(void)
317 idi_48_device
= platform_device_alloc(idi_48_driver
.driver
.name
, -1);
321 err
= platform_device_add(idi_48_device
);
323 goto err_platform_device
;
325 err
= platform_driver_probe(&idi_48_driver
, idi_48_probe
);
327 goto err_platform_driver
;
332 platform_device_del(idi_48_device
);
334 platform_device_put(idi_48_device
);
338 module_init(idi_48_init
);
339 module_exit(idi_48_exit
);
341 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
342 MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
343 MODULE_LICENSE("GPL");