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William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -05001/*
2 * GPIO driver for the ACCES 104-IDI-48 family
3 * Copyright (C) 2015 William Breathitt Gray
4 *
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.
8 *
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.
13 */
14#include <linux/bitops.h>
15#include <linux/device.h>
16#include <linux/errno.h>
17#include <linux/gpio/driver.h>
18#include <linux/io.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>
27
28static unsigned idi_48_base;
29module_param(idi_48_base, uint, 0);
30MODULE_PARM_DESC(idi_48_base, "ACCES 104-IDI-48 base address");
31static unsigned idi_48_irq;
32module_param(idi_48_irq, uint, 0);
33MODULE_PARM_DESC(idi_48_irq, "ACCES 104-IDI-48 interrupt line number");
34
35/**
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
William Breathitt Gray9ae48212015-12-15 18:52:44 -050039 * @ack_lock: synchronization lock to prevent IRQ handler race conditions
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050040 * @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
45 */
46struct idi_48_gpio {
47 struct gpio_chip chip;
48 spinlock_t lock;
William Breathitt Gray9ae48212015-12-15 18:52:44 -050049 spinlock_t ack_lock;
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050050 unsigned char irq_mask[6];
51 unsigned base;
52 unsigned extent;
53 unsigned irq;
54 unsigned char cos_enb;
55};
56
57static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
58{
59 return 1;
60}
61
62static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
63{
64 return 0;
65}
66
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050067static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
68{
Linus Walleij1f36bec2015-12-03 15:31:48 +010069 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050070 unsigned i;
71 const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 };
72 unsigned base_offset;
73 unsigned mask;
74
75 for (i = 0; i < 48; i += 8)
76 if (offset < i + 8) {
77 base_offset = register_offset[i / 8];
78 mask = BIT(offset - i);
79
80 return !!(inb(idi48gpio->base + base_offset) & mask);
81 }
82
83 /* The following line should never execute since offset < 48 */
84 return 0;
85}
86
87static void idi_48_irq_ack(struct irq_data *data)
88{
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050089}
90
91static void idi_48_irq_mask(struct irq_data *data)
92{
93 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
Linus Walleij1f36bec2015-12-03 15:31:48 +010094 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -050095 const unsigned offset = irqd_to_hwirq(data);
96 unsigned i;
97 unsigned mask;
98 unsigned boundary;
99 unsigned long flags;
100
101 for (i = 0; i < 48; i += 8)
102 if (offset < i + 8) {
103 mask = BIT(offset - i);
104 boundary = i / 8;
105
106 idi48gpio->irq_mask[boundary] &= ~mask;
107
108 if (!idi48gpio->irq_mask[boundary]) {
109 idi48gpio->cos_enb &= ~BIT(boundary);
110
111 spin_lock_irqsave(&idi48gpio->lock, flags);
112
113 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
114
115 spin_unlock_irqrestore(&idi48gpio->lock, flags);
116 }
117
118 return;
119 }
120}
121
122static void idi_48_irq_unmask(struct irq_data *data)
123{
124 struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
Linus Walleij1f36bec2015-12-03 15:31:48 +0100125 struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip);
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500126 const unsigned offset = irqd_to_hwirq(data);
127 unsigned i;
128 unsigned mask;
129 unsigned boundary;
130 unsigned prev_irq_mask;
131 unsigned long flags;
132
133 for (i = 0; i < 48; i += 8)
134 if (offset < i + 8) {
135 mask = BIT(offset - i);
136 boundary = i / 8;
137 prev_irq_mask = idi48gpio->irq_mask[boundary];
138
139 idi48gpio->irq_mask[boundary] |= mask;
140
141 if (!prev_irq_mask) {
142 idi48gpio->cos_enb |= BIT(boundary);
143
144 spin_lock_irqsave(&idi48gpio->lock, flags);
145
146 outb(idi48gpio->cos_enb, idi48gpio->base + 7);
147
148 spin_unlock_irqrestore(&idi48gpio->lock, flags);
149 }
150
151 return;
152 }
153}
154
155static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type)
156{
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)
160 return -EINVAL;
161
162 return 0;
163}
164
165static 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
171};
172
173static irqreturn_t idi_48_irq_handler(int irq, void *dev_id)
174{
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;
180 unsigned long gpio;
181 struct gpio_chip *const chip = &idi48gpio->chip;
182
William Breathitt Gray9ae48212015-12-15 18:52:44 -0500183 spin_lock(&idi48gpio->ack_lock);
184
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500185 spin_lock(&idi48gpio->lock);
186
187 cos_status = inb(idi48gpio->base + 7);
188
189 spin_unlock(&idi48gpio->lock);
190
191 /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */
William Breathitt Gray9ae48212015-12-15 18:52:44 -0500192 if (cos_status & BIT(6)) {
193 spin_unlock(&idi48gpio->ack_lock);
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500194 return IRQ_NONE;
William Breathitt Gray9ae48212015-12-15 18:52:44 -0500195 }
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500196
197 /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */
198 cos_status &= 0x3F;
199
200 for_each_set_bit(boundary, &cos_status, 6) {
201 irq_mask = idi48gpio->irq_mask[boundary];
202
203 for_each_set_bit(bit_num, &irq_mask, 8) {
204 gpio = bit_num + boundary * 8;
205
206 generic_handle_irq(irq_find_mapping(chip->irqdomain,
207 gpio));
208 }
209 }
210
William Breathitt Gray9ae48212015-12-15 18:52:44 -0500211 spin_unlock(&idi48gpio->ack_lock);
212
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500213 return IRQ_HANDLED;
214}
215
216static int __init idi_48_probe(struct platform_device *pdev)
217{
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);
223 int err;
224 const unsigned irq = idi_48_irq;
225
226 idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL);
227 if (!idi48gpio)
228 return -ENOMEM;
229
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);
233 err = -EBUSY;
234 goto err_lock_io_port;
235 }
236
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;
248
249 spin_lock_init(&idi48gpio->lock);
250
251 dev_set_drvdata(dev, idi48gpio);
252
Linus Walleij1f36bec2015-12-03 15:31:48 +0100253 err = gpiochip_add_data(&idi48gpio->chip, idi48gpio);
William Breathitt Gray6ddcf9b2015-11-23 12:54:50 -0500254 if (err) {
255 dev_err(dev, "GPIO registering failed (%d)\n", err);
256 goto err_gpio_register;
257 }
258
259 /* Disable IRQ by default */
260 outb(0, base + 7);
261 inb(base + 7);
262
263 err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0,
264 handle_edge_irq, IRQ_TYPE_NONE);
265 if (err) {
266 dev_err(dev, "Could not add irqchip (%d)\n", err);
267 goto err_gpiochip_irqchip_add;
268 }
269
270 err = request_irq(irq, idi_48_irq_handler, 0, name, idi48gpio);
271 if (err) {
272 dev_err(dev, "IRQ handler registering failed (%d)\n", err);
273 goto err_request_irq;
274 }
275
276 return 0;
277
278err_request_irq:
279err_gpiochip_irqchip_add:
280 gpiochip_remove(&idi48gpio->chip);
281err_gpio_register:
282 release_region(base, extent);
283err_lock_io_port:
284 return err;
285}
286
287static int idi_48_remove(struct platform_device *pdev)
288{
289 struct idi_48_gpio *const idi48gpio = platform_get_drvdata(pdev);
290
291 free_irq(idi48gpio->irq, idi48gpio);
292 gpiochip_remove(&idi48gpio->chip);
293 release_region(idi48gpio->base, idi48gpio->extent);
294
295 return 0;
296}
297
298static struct platform_device *idi_48_device;
299
300static struct platform_driver idi_48_driver = {
301 .driver = {
302 .name = "104-idi-48"
303 },
304 .remove = idi_48_remove
305};
306
307static void __exit idi_48_exit(void)
308{
309 platform_device_unregister(idi_48_device);
310 platform_driver_unregister(&idi_48_driver);
311}
312
313static int __init idi_48_init(void)
314{
315 int err;
316
317 idi_48_device = platform_device_alloc(idi_48_driver.driver.name, -1);
318 if (!idi_48_device)
319 return -ENOMEM;
320
321 err = platform_device_add(idi_48_device);
322 if (err)
323 goto err_platform_device;
324
325 err = platform_driver_probe(&idi_48_driver, idi_48_probe);
326 if (err)
327 goto err_platform_driver;
328
329 return 0;
330
331err_platform_driver:
332 platform_device_del(idi_48_device);
333err_platform_device:
334 platform_device_put(idi_48_device);
335 return err;
336}
337
338module_init(idi_48_init);
339module_exit(idi_48_exit);
340
341MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
342MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver");
343MODULE_LICENSE("GPL");