xref: /openbmc/linux/drivers/gpio/gpio-ws16c48.c (revision d2574c33) 
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/bitmap.h>
15 #include <linux/bitops.h>
16 #include <linux/device.h>
17 #include <linux/errno.h>
18 #include <linux/gpio/driver.h>
19 #include <linux/io.h>
20 #include <linux/ioport.h>
21 #include <linux/interrupt.h>
22 #include <linux/irqdesc.h>
23 #include <linux/isa.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/spinlock.h>
28 
29 #define WS16C48_EXTENT 16
30 #define MAX_NUM_WS16C48 max_num_isa_dev(WS16C48_EXTENT)
31 
32 static unsigned int base[MAX_NUM_WS16C48];
33 static unsigned int num_ws16c48;
34 module_param_hw_array(base, uint, ioport, &num_ws16c48, 0);
35 MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");
36 
37 static unsigned int irq[MAX_NUM_WS16C48];
38 module_param_hw_array(irq, uint, irq, NULL, 0);
39 MODULE_PARM_DESC(irq, "WinSystems WS16C48 interrupt line numbers");
40 
41 /**
42  * struct ws16c48_gpio - GPIO device private data structure
43  * @chip:	instance of the gpio_chip
44  * @io_state:	bit I/O state (whether bit is set to input or output)
45  * @out_state:	output bits state
46  * @lock:	synchronization lock to prevent I/O race conditions
47  * @irq_mask:	I/O bits affected by interrupts
48  * @flow_mask:	IRQ flow type mask for the respective I/O bits
49  * @base:	base port address of the GPIO device
50  */
51 struct ws16c48_gpio {
52 	struct gpio_chip chip;
53 	unsigned char io_state[6];
54 	unsigned char out_state[6];
55 	raw_spinlock_t lock;
56 	unsigned long irq_mask;
57 	unsigned long flow_mask;
58 	unsigned base;
59 };
60 
61 static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
62 {
63 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
64 	const unsigned port = offset / 8;
65 	const unsigned mask = BIT(offset % 8);
66 
67 	return !!(ws16c48gpio->io_state[port] & mask);
68 }
69 
70 static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
71 {
72 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
73 	const unsigned port = offset / 8;
74 	const unsigned mask = BIT(offset % 8);
75 	unsigned long flags;
76 
77 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
78 
79 	ws16c48gpio->io_state[port] |= mask;
80 	ws16c48gpio->out_state[port] &= ~mask;
81 	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
82 
83 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
84 
85 	return 0;
86 }
87 
88 static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
89 	unsigned offset, int value)
90 {
91 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
92 	const unsigned port = offset / 8;
93 	const unsigned mask = BIT(offset % 8);
94 	unsigned long flags;
95 
96 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
97 
98 	ws16c48gpio->io_state[port] &= ~mask;
99 	if (value)
100 		ws16c48gpio->out_state[port] |= mask;
101 	else
102 		ws16c48gpio->out_state[port] &= ~mask;
103 	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
104 
105 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
106 
107 	return 0;
108 }
109 
110 static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
111 {
112 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
113 	const unsigned port = offset / 8;
114 	const unsigned mask = BIT(offset % 8);
115 	unsigned long flags;
116 	unsigned port_state;
117 
118 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
119 
120 	/* ensure that GPIO is set for input */
121 	if (!(ws16c48gpio->io_state[port] & mask)) {
122 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
123 		return -EINVAL;
124 	}
125 
126 	port_state = inb(ws16c48gpio->base + port);
127 
128 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
129 
130 	return !!(port_state & mask);
131 }
132 
133 static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
134 	unsigned long *mask, unsigned long *bits)
135 {
136 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
137 	const unsigned int gpio_reg_size = 8;
138 	size_t i;
139 	const size_t num_ports = chip->ngpio / gpio_reg_size;
140 	unsigned int bits_offset;
141 	size_t word_index;
142 	unsigned int word_offset;
143 	unsigned long word_mask;
144 	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
145 	unsigned long port_state;
146 
147 	/* clear bits array to a clean slate */
148 	bitmap_zero(bits, chip->ngpio);
149 
150 	/* get bits are evaluated a gpio port register at a time */
151 	for (i = 0; i < num_ports; i++) {
152 		/* gpio offset in bits array */
153 		bits_offset = i * gpio_reg_size;
154 
155 		/* word index for bits array */
156 		word_index = BIT_WORD(bits_offset);
157 
158 		/* gpio offset within current word of bits array */
159 		word_offset = bits_offset % BITS_PER_LONG;
160 
161 		/* mask of get bits for current gpio within current word */
162 		word_mask = mask[word_index] & (port_mask << word_offset);
163 		if (!word_mask) {
164 			/* no get bits in this port so skip to next one */
165 			continue;
166 		}
167 
168 		/* read bits from current gpio port */
169 		port_state = inb(ws16c48gpio->base + i);
170 
171 		/* store acquired bits at respective bits array offset */
172 		bits[word_index] |= (port_state << word_offset) & word_mask;
173 	}
174 
175 	return 0;
176 }
177 
178 static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
179 {
180 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
181 	const unsigned port = offset / 8;
182 	const unsigned mask = BIT(offset % 8);
183 	unsigned long flags;
184 
185 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
186 
187 	/* ensure that GPIO is set for output */
188 	if (ws16c48gpio->io_state[port] & mask) {
189 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
190 		return;
191 	}
192 
193 	if (value)
194 		ws16c48gpio->out_state[port] |= mask;
195 	else
196 		ws16c48gpio->out_state[port] &= ~mask;
197 	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
198 
199 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
200 }
201 
202 static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
203 	unsigned long *mask, unsigned long *bits)
204 {
205 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
206 	unsigned int i;
207 	const unsigned int gpio_reg_size = 8;
208 	unsigned int port;
209 	unsigned int iomask;
210 	unsigned int bitmask;
211 	unsigned long flags;
212 
213 	/* set bits are evaluated a gpio register size at a time */
214 	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
215 		/* no more set bits in this mask word; skip to the next word */
216 		if (!mask[BIT_WORD(i)]) {
217 			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
218 			continue;
219 		}
220 
221 		port = i / gpio_reg_size;
222 
223 		/* mask out GPIO configured for input */
224 		iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
225 		bitmask = iomask & bits[BIT_WORD(i)];
226 
227 		raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
228 
229 		/* update output state data and set device gpio register */
230 		ws16c48gpio->out_state[port] &= ~iomask;
231 		ws16c48gpio->out_state[port] |= bitmask;
232 		outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
233 
234 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
235 
236 		/* prepare for next gpio register set */
237 		mask[BIT_WORD(i)] >>= gpio_reg_size;
238 		bits[BIT_WORD(i)] >>= gpio_reg_size;
239 	}
240 }
241 
242 static void ws16c48_irq_ack(struct irq_data *data)
243 {
244 	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
245 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
246 	const unsigned long offset = irqd_to_hwirq(data);
247 	const unsigned port = offset / 8;
248 	const unsigned mask = BIT(offset % 8);
249 	unsigned long flags;
250 	unsigned port_state;
251 
252 	/* only the first 3 ports support interrupts */
253 	if (port > 2)
254 		return;
255 
256 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
257 
258 	port_state = ws16c48gpio->irq_mask >> (8*port);
259 
260 	outb(0x80, ws16c48gpio->base + 7);
261 	outb(port_state & ~mask, ws16c48gpio->base + 8 + port);
262 	outb(port_state | mask, ws16c48gpio->base + 8 + port);
263 	outb(0xC0, ws16c48gpio->base + 7);
264 
265 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
266 }
267 
268 static void ws16c48_irq_mask(struct irq_data *data)
269 {
270 	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
271 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
272 	const unsigned long offset = irqd_to_hwirq(data);
273 	const unsigned long mask = BIT(offset);
274 	const unsigned port = offset / 8;
275 	unsigned long flags;
276 
277 	/* only the first 3 ports support interrupts */
278 	if (port > 2)
279 		return;
280 
281 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
282 
283 	ws16c48gpio->irq_mask &= ~mask;
284 
285 	outb(0x80, ws16c48gpio->base + 7);
286 	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
287 	outb(0xC0, ws16c48gpio->base + 7);
288 
289 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
290 }
291 
292 static void ws16c48_irq_unmask(struct irq_data *data)
293 {
294 	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
295 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
296 	const unsigned long offset = irqd_to_hwirq(data);
297 	const unsigned long mask = BIT(offset);
298 	const unsigned port = offset / 8;
299 	unsigned long flags;
300 
301 	/* only the first 3 ports support interrupts */
302 	if (port > 2)
303 		return;
304 
305 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
306 
307 	ws16c48gpio->irq_mask |= mask;
308 
309 	outb(0x80, ws16c48gpio->base + 7);
310 	outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
311 	outb(0xC0, ws16c48gpio->base + 7);
312 
313 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
314 }
315 
316 static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
317 {
318 	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
319 	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
320 	const unsigned long offset = irqd_to_hwirq(data);
321 	const unsigned long mask = BIT(offset);
322 	const unsigned port = offset / 8;
323 	unsigned long flags;
324 
325 	/* only the first 3 ports support interrupts */
326 	if (port > 2)
327 		return -EINVAL;
328 
329 	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
330 
331 	switch (flow_type) {
332 	case IRQ_TYPE_NONE:
333 		break;
334 	case IRQ_TYPE_EDGE_RISING:
335 		ws16c48gpio->flow_mask |= mask;
336 		break;
337 	case IRQ_TYPE_EDGE_FALLING:
338 		ws16c48gpio->flow_mask &= ~mask;
339 		break;
340 	default:
341 		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
342 		return -EINVAL;
343 	}
344 
345 	outb(0x40, ws16c48gpio->base + 7);
346 	outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
347 	outb(0xC0, ws16c48gpio->base + 7);
348 
349 	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
350 
351 	return 0;
352 }
353 
354 static struct irq_chip ws16c48_irqchip = {
355 	.name = "ws16c48",
356 	.irq_ack = ws16c48_irq_ack,
357 	.irq_mask = ws16c48_irq_mask,
358 	.irq_unmask = ws16c48_irq_unmask,
359 	.irq_set_type = ws16c48_irq_set_type
360 };
361 
362 static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)
363 {
364 	struct ws16c48_gpio *const ws16c48gpio = dev_id;
365 	struct gpio_chip *const chip = &ws16c48gpio->chip;
366 	unsigned long int_pending;
367 	unsigned long port;
368 	unsigned long int_id;
369 	unsigned long gpio;
370 
371 	int_pending = inb(ws16c48gpio->base + 6) & 0x7;
372 	if (!int_pending)
373 		return IRQ_NONE;
374 
375 	/* loop until all pending interrupts are handled */
376 	do {
377 		for_each_set_bit(port, &int_pending, 3) {
378 			int_id = inb(ws16c48gpio->base + 8 + port);
379 			for_each_set_bit(gpio, &int_id, 8)
380 				generic_handle_irq(irq_find_mapping(
381 					chip->irq.domain, gpio + 8*port));
382 		}
383 
384 		int_pending = inb(ws16c48gpio->base + 6) & 0x7;
385 	} while (int_pending);
386 
387 	return IRQ_HANDLED;
388 }
389 
390 #define WS16C48_NGPIO 48
391 static const char *ws16c48_names[WS16C48_NGPIO] = {
392 	"Port 0 Bit 0", "Port 0 Bit 1", "Port 0 Bit 2", "Port 0 Bit 3",
393 	"Port 0 Bit 4", "Port 0 Bit 5", "Port 0 Bit 6", "Port 0 Bit 7",
394 	"Port 1 Bit 0", "Port 1 Bit 1", "Port 1 Bit 2", "Port 1 Bit 3",
395 	"Port 1 Bit 4", "Port 1 Bit 5", "Port 1 Bit 6", "Port 1 Bit 7",
396 	"Port 2 Bit 0", "Port 2 Bit 1", "Port 2 Bit 2", "Port 2 Bit 3",
397 	"Port 2 Bit 4", "Port 2 Bit 5", "Port 2 Bit 6", "Port 2 Bit 7",
398 	"Port 3 Bit 0", "Port 3 Bit 1", "Port 3 Bit 2", "Port 3 Bit 3",
399 	"Port 3 Bit 4", "Port 3 Bit 5", "Port 3 Bit 6", "Port 3 Bit 7",
400 	"Port 4 Bit 0", "Port 4 Bit 1", "Port 4 Bit 2", "Port 4 Bit 3",
401 	"Port 4 Bit 4", "Port 4 Bit 5", "Port 4 Bit 6", "Port 4 Bit 7",
402 	"Port 5 Bit 0", "Port 5 Bit 1", "Port 5 Bit 2", "Port 5 Bit 3",
403 	"Port 5 Bit 4", "Port 5 Bit 5", "Port 5 Bit 6", "Port 5 Bit 7"
404 };
405 
406 static int ws16c48_probe(struct device *dev, unsigned int id)
407 {
408 	struct ws16c48_gpio *ws16c48gpio;
409 	const char *const name = dev_name(dev);
410 	int err;
411 
412 	ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);
413 	if (!ws16c48gpio)
414 		return -ENOMEM;
415 
416 	if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) {
417 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
418 			base[id], base[id] + WS16C48_EXTENT);
419 		return -EBUSY;
420 	}
421 
422 	ws16c48gpio->chip.label = name;
423 	ws16c48gpio->chip.parent = dev;
424 	ws16c48gpio->chip.owner = THIS_MODULE;
425 	ws16c48gpio->chip.base = -1;
426 	ws16c48gpio->chip.ngpio = WS16C48_NGPIO;
427 	ws16c48gpio->chip.names = ws16c48_names;
428 	ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;
429 	ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
430 	ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
431 	ws16c48gpio->chip.get = ws16c48_gpio_get;
432 	ws16c48gpio->chip.get_multiple = ws16c48_gpio_get_multiple;
433 	ws16c48gpio->chip.set = ws16c48_gpio_set;
434 	ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
435 	ws16c48gpio->base = base[id];
436 
437 	raw_spin_lock_init(&ws16c48gpio->lock);
438 
439 	err = devm_gpiochip_add_data(dev, &ws16c48gpio->chip, ws16c48gpio);
440 	if (err) {
441 		dev_err(dev, "GPIO registering failed (%d)\n", err);
442 		return err;
443 	}
444 
445 	/* Disable IRQ by default */
446 	outb(0x80, base[id] + 7);
447 	outb(0, base[id] + 8);
448 	outb(0, base[id] + 9);
449 	outb(0, base[id] + 10);
450 	outb(0xC0, base[id] + 7);
451 
452 	err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0,
453 		handle_edge_irq, IRQ_TYPE_NONE);
454 	if (err) {
455 		dev_err(dev, "Could not add irqchip (%d)\n", err);
456 		return err;
457 	}
458 
459 	err = devm_request_irq(dev, irq[id], ws16c48_irq_handler, IRQF_SHARED,
460 		name, ws16c48gpio);
461 	if (err) {
462 		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
463 		return err;
464 	}
465 
466 	return 0;
467 }
468 
469 static struct isa_driver ws16c48_driver = {
470 	.probe = ws16c48_probe,
471 	.driver = {
472 		.name = "ws16c48"
473 	},
474 };
475 
476 module_isa_driver(ws16c48_driver, num_ws16c48);
477 
478 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
479 MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");
480 MODULE_LICENSE("GPL v2");
481