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9c26df9b WBG |
1 | /* |
2 | * GPIO driver for the WinSystems WS16C48 | |
3 | * Copyright (C) 2016 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 | ||
28 | static unsigned ws16c48_base; | |
29 | module_param(ws16c48_base, uint, 0); | |
30 | MODULE_PARM_DESC(ws16c48_base, "WinSystems WS16C48 base address"); | |
31 | static unsigned ws16c48_irq; | |
32 | module_param(ws16c48_irq, uint, 0); | |
33 | MODULE_PARM_DESC(ws16c48_irq, "WinSystems WS16C48 interrupt line number"); | |
34 | ||
35 | /** | |
36 | * struct ws16c48_gpio - GPIO device private data structure | |
37 | * @chip: instance of the gpio_chip | |
38 | * @io_state: bit I/O state (whether bit is set to input or output) | |
39 | * @out_state: output bits state | |
40 | * @lock: synchronization lock to prevent I/O race conditions | |
41 | * @irq_mask: I/O bits affected by interrupts | |
42 | * @flow_mask: IRQ flow type mask for the respective I/O bits | |
43 | * @base: base port address of the GPIO device | |
44 | * @extent: extent of port address region of the GPIO device | |
45 | * @irq: Interrupt line number | |
46 | */ | |
47 | struct ws16c48_gpio { | |
48 | struct gpio_chip chip; | |
49 | unsigned char io_state[6]; | |
50 | unsigned char out_state[6]; | |
51 | spinlock_t lock; | |
52 | unsigned long irq_mask; | |
53 | unsigned long flow_mask; | |
54 | unsigned base; | |
55 | unsigned extent; | |
56 | unsigned irq; | |
57 | }; | |
58 | ||
59 | static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset) | |
60 | { | |
61 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
62 | const unsigned port = offset / 8; | |
63 | const unsigned mask = BIT(offset % 8); | |
64 | ||
65 | return !!(ws16c48gpio->io_state[port] & mask); | |
66 | } | |
67 | ||
68 | static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset) | |
69 | { | |
70 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
71 | const unsigned port = offset / 8; | |
72 | const unsigned mask = BIT(offset % 8); | |
73 | unsigned long flags; | |
74 | ||
75 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
76 | ||
77 | ws16c48gpio->io_state[port] |= mask; | |
78 | ws16c48gpio->out_state[port] &= ~mask; | |
79 | outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); | |
80 | ||
81 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
82 | ||
83 | return 0; | |
84 | } | |
85 | ||
86 | static int ws16c48_gpio_direction_output(struct gpio_chip *chip, | |
87 | unsigned offset, int value) | |
88 | { | |
89 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
90 | const unsigned port = offset / 8; | |
91 | const unsigned mask = BIT(offset % 8); | |
92 | unsigned long flags; | |
93 | ||
94 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
95 | ||
96 | ws16c48gpio->io_state[port] &= ~mask; | |
97 | if (value) | |
98 | ws16c48gpio->out_state[port] |= mask; | |
99 | else | |
100 | ws16c48gpio->out_state[port] &= ~mask; | |
101 | outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); | |
102 | ||
103 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
104 | ||
105 | return 0; | |
106 | } | |
107 | ||
108 | static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset) | |
109 | { | |
110 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
111 | const unsigned port = offset / 8; | |
112 | const unsigned mask = BIT(offset % 8); | |
113 | unsigned long flags; | |
114 | unsigned port_state; | |
115 | ||
116 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
117 | ||
118 | /* ensure that GPIO is set for input */ | |
119 | if (!(ws16c48gpio->io_state[port] & mask)) { | |
120 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
121 | return -EINVAL; | |
122 | } | |
123 | ||
124 | port_state = inb(ws16c48gpio->base + port); | |
125 | ||
126 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
127 | ||
128 | return !!(port_state & mask); | |
129 | } | |
130 | ||
131 | static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value) | |
132 | { | |
133 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
134 | const unsigned port = offset / 8; | |
135 | const unsigned mask = BIT(offset % 8); | |
136 | unsigned long flags; | |
137 | ||
138 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
139 | ||
140 | /* ensure that GPIO is set for output */ | |
141 | if (ws16c48gpio->io_state[port] & mask) { | |
142 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
143 | return; | |
144 | } | |
145 | ||
146 | if (value) | |
147 | ws16c48gpio->out_state[port] |= mask; | |
148 | else | |
149 | ws16c48gpio->out_state[port] &= ~mask; | |
150 | outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); | |
151 | ||
152 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
153 | } | |
154 | ||
155 | static void ws16c48_irq_ack(struct irq_data *data) | |
156 | { | |
157 | struct gpio_chip *chip = irq_data_get_irq_chip_data(data); | |
158 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
159 | const unsigned long offset = irqd_to_hwirq(data); | |
160 | const unsigned port = offset / 8; | |
161 | const unsigned mask = BIT(offset % 8); | |
162 | unsigned long flags; | |
163 | unsigned port_state; | |
164 | ||
165 | /* only the first 3 ports support interrupts */ | |
166 | if (port > 2) | |
167 | return; | |
168 | ||
169 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
170 | ||
171 | port_state = ws16c48gpio->irq_mask >> (8*port); | |
172 | ||
173 | outb(0x80, ws16c48gpio->base + 7); | |
174 | outb(port_state & ~mask, ws16c48gpio->base + 8 + port); | |
175 | outb(port_state | mask, ws16c48gpio->base + 8 + port); | |
176 | outb(0xC0, ws16c48gpio->base + 7); | |
177 | ||
178 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
179 | } | |
180 | ||
181 | static void ws16c48_irq_mask(struct irq_data *data) | |
182 | { | |
183 | struct gpio_chip *chip = irq_data_get_irq_chip_data(data); | |
184 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
185 | const unsigned long offset = irqd_to_hwirq(data); | |
186 | const unsigned long mask = BIT(offset); | |
187 | const unsigned port = offset / 8; | |
188 | unsigned long flags; | |
189 | ||
190 | /* only the first 3 ports support interrupts */ | |
191 | if (port > 2) | |
192 | return; | |
193 | ||
194 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
195 | ||
196 | ws16c48gpio->irq_mask &= ~mask; | |
197 | ||
198 | outb(0x80, ws16c48gpio->base + 7); | |
199 | outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port); | |
200 | outb(0xC0, ws16c48gpio->base + 7); | |
201 | ||
202 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
203 | } | |
204 | ||
205 | static void ws16c48_irq_unmask(struct irq_data *data) | |
206 | { | |
207 | struct gpio_chip *chip = irq_data_get_irq_chip_data(data); | |
208 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
209 | const unsigned long offset = irqd_to_hwirq(data); | |
210 | const unsigned long mask = BIT(offset); | |
211 | const unsigned port = offset / 8; | |
212 | unsigned long flags; | |
213 | ||
214 | /* only the first 3 ports support interrupts */ | |
215 | if (port > 2) | |
216 | return; | |
217 | ||
218 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
219 | ||
220 | ws16c48gpio->irq_mask |= mask; | |
221 | ||
222 | outb(0x80, ws16c48gpio->base + 7); | |
223 | outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port); | |
224 | outb(0xC0, ws16c48gpio->base + 7); | |
225 | ||
226 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
227 | } | |
228 | ||
229 | static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type) | |
230 | { | |
231 | struct gpio_chip *chip = irq_data_get_irq_chip_data(data); | |
232 | struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); | |
233 | const unsigned long offset = irqd_to_hwirq(data); | |
234 | const unsigned long mask = BIT(offset); | |
235 | const unsigned port = offset / 8; | |
236 | unsigned long flags; | |
237 | ||
238 | /* only the first 3 ports support interrupts */ | |
239 | if (port > 2) | |
240 | return -EINVAL; | |
241 | ||
242 | spin_lock_irqsave(&ws16c48gpio->lock, flags); | |
243 | ||
244 | switch (flow_type) { | |
245 | case IRQ_TYPE_NONE: | |
246 | break; | |
247 | case IRQ_TYPE_EDGE_RISING: | |
248 | ws16c48gpio->flow_mask |= mask; | |
249 | break; | |
250 | case IRQ_TYPE_EDGE_FALLING: | |
251 | ws16c48gpio->flow_mask &= ~mask; | |
252 | break; | |
253 | default: | |
254 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
255 | return -EINVAL; | |
256 | } | |
257 | ||
258 | outb(0x40, ws16c48gpio->base + 7); | |
259 | outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port); | |
260 | outb(0xC0, ws16c48gpio->base + 7); | |
261 | ||
262 | spin_unlock_irqrestore(&ws16c48gpio->lock, flags); | |
263 | ||
264 | return 0; | |
265 | } | |
266 | ||
267 | static struct irq_chip ws16c48_irqchip = { | |
268 | .name = "ws16c48", | |
269 | .irq_ack = ws16c48_irq_ack, | |
270 | .irq_mask = ws16c48_irq_mask, | |
271 | .irq_unmask = ws16c48_irq_unmask, | |
272 | .irq_set_type = ws16c48_irq_set_type | |
273 | }; | |
274 | ||
275 | static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id) | |
276 | { | |
277 | struct ws16c48_gpio *const ws16c48gpio = dev_id; | |
278 | struct gpio_chip *const chip = &ws16c48gpio->chip; | |
279 | unsigned long int_pending; | |
280 | unsigned long port; | |
281 | unsigned long int_id; | |
282 | unsigned long gpio; | |
283 | ||
284 | int_pending = inb(ws16c48gpio->base + 6) & 0x7; | |
285 | if (!int_pending) | |
286 | return IRQ_NONE; | |
287 | ||
288 | /* loop until all pending interrupts are handled */ | |
289 | do { | |
290 | for_each_set_bit(port, &int_pending, 3) { | |
291 | int_id = inb(ws16c48gpio->base + 8 + port); | |
292 | for_each_set_bit(gpio, &int_id, 8) | |
293 | generic_handle_irq(irq_find_mapping( | |
294 | chip->irqdomain, gpio + 8*port)); | |
295 | } | |
296 | ||
297 | int_pending = inb(ws16c48gpio->base + 6) & 0x7; | |
298 | } while (int_pending); | |
299 | ||
300 | return IRQ_HANDLED; | |
301 | } | |
302 | ||
303 | static int __init ws16c48_probe(struct platform_device *pdev) | |
304 | { | |
305 | struct device *dev = &pdev->dev; | |
306 | struct ws16c48_gpio *ws16c48gpio; | |
307 | const unsigned base = ws16c48_base; | |
308 | const unsigned extent = 16; | |
309 | const char *const name = dev_name(dev); | |
310 | int err; | |
311 | const unsigned irq = ws16c48_irq; | |
312 | ||
313 | ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL); | |
314 | if (!ws16c48gpio) | |
315 | return -ENOMEM; | |
316 | ||
317 | if (!request_region(base, extent, name)) { | |
318 | dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n", | |
319 | name, base, base + extent); | |
320 | err = -EBUSY; | |
321 | goto err_lock_io_port; | |
322 | } | |
323 | ||
324 | ws16c48gpio->chip.label = name; | |
325 | ws16c48gpio->chip.parent = dev; | |
326 | ws16c48gpio->chip.owner = THIS_MODULE; | |
327 | ws16c48gpio->chip.base = -1; | |
328 | ws16c48gpio->chip.ngpio = 48; | |
329 | ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction; | |
330 | ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input; | |
331 | ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output; | |
332 | ws16c48gpio->chip.get = ws16c48_gpio_get; | |
333 | ws16c48gpio->chip.set = ws16c48_gpio_set; | |
334 | ws16c48gpio->base = base; | |
335 | ws16c48gpio->extent = extent; | |
336 | ws16c48gpio->irq = irq; | |
337 | ||
338 | spin_lock_init(&ws16c48gpio->lock); | |
339 | ||
340 | dev_set_drvdata(dev, ws16c48gpio); | |
341 | ||
342 | err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio); | |
343 | if (err) { | |
344 | dev_err(dev, "GPIO registering failed (%d)\n", err); | |
345 | goto err_gpio_register; | |
346 | } | |
347 | ||
348 | /* Disable IRQ by default */ | |
349 | outb(0x80, base + 7); | |
350 | outb(0, base + 8); | |
351 | outb(0, base + 9); | |
352 | outb(0, base + 10); | |
353 | outb(0xC0, base + 7); | |
354 | ||
355 | err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0, | |
356 | handle_edge_irq, IRQ_TYPE_NONE); | |
357 | if (err) { | |
358 | dev_err(dev, "Could not add irqchip (%d)\n", err); | |
359 | goto err_gpiochip_irqchip_add; | |
360 | } | |
361 | ||
362 | err = request_irq(irq, ws16c48_irq_handler, IRQF_SHARED, name, | |
363 | ws16c48gpio); | |
364 | if (err) { | |
365 | dev_err(dev, "IRQ handler registering failed (%d)\n", err); | |
366 | goto err_request_irq; | |
367 | } | |
368 | ||
369 | return 0; | |
370 | ||
371 | err_request_irq: | |
372 | err_gpiochip_irqchip_add: | |
373 | gpiochip_remove(&ws16c48gpio->chip); | |
374 | err_gpio_register: | |
375 | release_region(base, extent); | |
376 | err_lock_io_port: | |
377 | return err; | |
378 | } | |
379 | ||
380 | static int ws16c48_remove(struct platform_device *pdev) | |
381 | { | |
382 | struct ws16c48_gpio *const ws16c48gpio = platform_get_drvdata(pdev); | |
383 | ||
384 | free_irq(ws16c48gpio->irq, ws16c48gpio); | |
385 | gpiochip_remove(&ws16c48gpio->chip); | |
386 | release_region(ws16c48gpio->base, ws16c48gpio->extent); | |
387 | ||
388 | return 0; | |
389 | } | |
390 | ||
391 | static struct platform_device *ws16c48_device; | |
392 | ||
393 | static struct platform_driver ws16c48_driver = { | |
394 | .driver = { | |
395 | .name = "ws16c48" | |
396 | }, | |
397 | .remove = ws16c48_remove | |
398 | }; | |
399 | ||
400 | static void __exit ws16c48_exit(void) | |
401 | { | |
402 | platform_device_unregister(ws16c48_device); | |
403 | platform_driver_unregister(&ws16c48_driver); | |
404 | } | |
405 | ||
406 | static int __init ws16c48_init(void) | |
407 | { | |
408 | int err; | |
409 | ||
410 | ws16c48_device = platform_device_alloc(ws16c48_driver.driver.name, -1); | |
411 | if (!ws16c48_device) | |
412 | return -ENOMEM; | |
413 | ||
414 | err = platform_device_add(ws16c48_device); | |
415 | if (err) | |
416 | goto err_platform_device; | |
417 | ||
418 | err = platform_driver_probe(&ws16c48_driver, ws16c48_probe); | |
419 | if (err) | |
420 | goto err_platform_driver; | |
421 | ||
422 | return 0; | |
423 | ||
424 | err_platform_driver: | |
425 | platform_device_del(ws16c48_device); | |
426 | err_platform_device: | |
427 | platform_device_put(ws16c48_device); | |
428 | return err; | |
429 | } | |
430 | ||
431 | module_init(ws16c48_init); | |
432 | module_exit(ws16c48_exit); | |
433 | ||
434 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
435 | MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver"); | |
436 | MODULE_LICENSE("GPL"); |