1/*
2 * GPIO driver for the Diamond Systems GPIO-MM
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 * This driver supports the following Diamond Systems devices: GPIO-MM and
15 * GPIO-MM-12.
16 */
17#include <linux/bitmap.h>
18#include <linux/bitops.h>
19#include <linux/device.h>
20#include <linux/errno.h>
21#include <linux/gpio/driver.h>
22#include <linux/io.h>
23#include <linux/ioport.h>
24#include <linux/isa.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/spinlock.h>
29
30#define GPIOMM_EXTENT 8
31#define MAX_NUM_GPIOMM max_num_isa_dev(GPIOMM_EXTENT)
32
33static unsigned int base[MAX_NUM_GPIOMM];
34static unsigned int num_gpiomm;
35module_param_hw_array(base, uint, ioport, &num_gpiomm, 0);
36MODULE_PARM_DESC(base, "Diamond Systems GPIO-MM base addresses");
37
38/**
39 * struct gpiomm_gpio - GPIO device private data structure
40 * @chip: instance of the gpio_chip
41 * @io_state: bit I/O state (whether bit is set to input or output)
42 * @out_state: output bits state
43 * @control: Control registers state
44 * @lock: synchronization lock to prevent I/O race conditions
45 * @base: base port address of the GPIO device
46 */
47struct gpiomm_gpio {
48 struct gpio_chip chip;
49 unsigned char io_state[6];
50 unsigned char out_state[6];
51 unsigned char control[2];
52 spinlock_t lock;
53 unsigned int base;
54};
55
56static int gpiomm_gpio_get_direction(struct gpio_chip *chip,
57 unsigned int offset)
58{
59 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
60 const unsigned int port = offset / 8;
61 const unsigned int mask = BIT(offset % 8);
62
63 return !!(gpiommgpio->io_state[port] & mask);
64}
65
66static int gpiomm_gpio_direction_input(struct gpio_chip *chip,
67 unsigned int offset)
68{
69 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
70 const unsigned int io_port = offset / 8;
71 const unsigned int control_port = io_port / 3;
72 const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
73 unsigned long flags;
74 unsigned int control;
75
76 spin_lock_irqsave(&gpiommgpio->lock, flags);
77
78 /* Check if configuring Port C */
79 if (io_port == 2 || io_port == 5) {
80 /* Port C can be configured by nibble */
81 if (offset % 8 > 3) {
82 gpiommgpio->io_state[io_port] |= 0xF0;
83 gpiommgpio->control[control_port] |= BIT(3);
84 } else {
85 gpiommgpio->io_state[io_port] |= 0x0F;
86 gpiommgpio->control[control_port] |= BIT(0);
87 }
88 } else {
89 gpiommgpio->io_state[io_port] |= 0xFF;
90 if (io_port == 0 || io_port == 3)
91 gpiommgpio->control[control_port] |= BIT(4);
92 else
93 gpiommgpio->control[control_port] |= BIT(1);
94 }
95
96 control = BIT(7) | gpiommgpio->control[control_port];
97 outb(control, control_addr);
98
99 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
100
101 return 0;
102}
103
104static int gpiomm_gpio_direction_output(struct gpio_chip *chip,
105 unsigned int offset, int value)
106{
107 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
108 const unsigned int io_port = offset / 8;
109 const unsigned int control_port = io_port / 3;
110 const unsigned int mask = BIT(offset % 8);
111 const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
112 const unsigned int out_port = (io_port > 2) ? io_port + 1 : io_port;
113 unsigned long flags;
114 unsigned int control;
115
116 spin_lock_irqsave(&gpiommgpio->lock, flags);
117
118 /* Check if configuring Port C */
119 if (io_port == 2 || io_port == 5) {
120 /* Port C can be configured by nibble */
121 if (offset % 8 > 3) {
122 gpiommgpio->io_state[io_port] &= 0x0F;
123 gpiommgpio->control[control_port] &= ~BIT(3);
124 } else {
125 gpiommgpio->io_state[io_port] &= 0xF0;
126 gpiommgpio->control[control_port] &= ~BIT(0);
127 }
128 } else {
129 gpiommgpio->io_state[io_port] &= 0x00;
130 if (io_port == 0 || io_port == 3)
131 gpiommgpio->control[control_port] &= ~BIT(4);
132 else
133 gpiommgpio->control[control_port] &= ~BIT(1);
134 }
135
136 if (value)
137 gpiommgpio->out_state[io_port] |= mask;
138 else
139 gpiommgpio->out_state[io_port] &= ~mask;
140
141 control = BIT(7) | gpiommgpio->control[control_port];
142 outb(control, control_addr);
143
144 outb(gpiommgpio->out_state[io_port], gpiommgpio->base + out_port);
145
146 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
147
148 return 0;
149}
150
151static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
152{
153 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
154 const unsigned int port = offset / 8;
155 const unsigned int mask = BIT(offset % 8);
156 const unsigned int in_port = (port > 2) ? port + 1 : port;
157 unsigned long flags;
158 unsigned int port_state;
159
160 spin_lock_irqsave(&gpiommgpio->lock, flags);
161
162 /* ensure that GPIO is set for input */
163 if (!(gpiommgpio->io_state[port] & mask)) {
164 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
165 return -EINVAL;
166 }
167
168 port_state = inb(gpiommgpio->base + in_port);
169
170 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
171
172 return !!(port_state & mask);
173}
174
175static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
176 unsigned long *bits)
177{
178 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
179 size_t i;
180 static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
181 const unsigned int gpio_reg_size = 8;
182 unsigned int bits_offset;
183 size_t word_index;
184 unsigned int word_offset;
185 unsigned long word_mask;
186 const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
187 unsigned long port_state;
188
189 /* clear bits array to a clean slate */
190 bitmap_zero(bits, chip->ngpio);
191
192 /* get bits are evaluated a gpio port register at a time */
193 for (i = 0; i < ARRAY_SIZE(ports); i++) {
194 /* gpio offset in bits array */
195 bits_offset = i * gpio_reg_size;
196
197 /* word index for bits array */
198 word_index = BIT_WORD(bits_offset);
199
200 /* gpio offset within current word of bits array */
201 word_offset = bits_offset % BITS_PER_LONG;
202
203 /* mask of get bits for current gpio within current word */
204 word_mask = mask[word_index] & (port_mask << word_offset);
205 if (!word_mask) {
206 /* no get bits in this port so skip to next one */
207 continue;
208 }
209
210 /* read bits from current gpio port */
211 port_state = inb(gpiommgpio->base + ports[i]);
212
213 /* store acquired bits at respective bits array offset */
214 bits[word_index] |= (port_state << word_offset) & word_mask;
215 }
216
217 return 0;
218}
219
220static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
221 int value)
222{
223 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
224 const unsigned int port = offset / 8;
225 const unsigned int mask = BIT(offset % 8);
226 const unsigned int out_port = (port > 2) ? port + 1 : port;
227 unsigned long flags;
228
229 spin_lock_irqsave(&gpiommgpio->lock, flags);
230
231 if (value)
232 gpiommgpio->out_state[port] |= mask;
233 else
234 gpiommgpio->out_state[port] &= ~mask;
235
236 outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);
237
238 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
239}
240
241static void gpiomm_gpio_set_multiple(struct gpio_chip *chip,
242 unsigned long *mask, unsigned long *bits)
243{
244 struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
245 unsigned int i;
246 const unsigned int gpio_reg_size = 8;
247 unsigned int port;
248 unsigned int out_port;
249 unsigned int bitmask;
250 unsigned long flags;
251
252 /* set bits are evaluated a gpio register size at a time */
253 for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
254 /* no more set bits in this mask word; skip to the next word */
255 if (!mask[BIT_WORD(i)]) {
256 i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
257 continue;
258 }
259
260 port = i / gpio_reg_size;
261 out_port = (port > 2) ? port + 1 : port;
262 bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];
263
264 spin_lock_irqsave(&gpiommgpio->lock, flags);
265
266 /* update output state data and set device gpio register */
267 gpiommgpio->out_state[port] &= ~mask[BIT_WORD(i)];
268 gpiommgpio->out_state[port] |= bitmask;
269 outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);
270
271 spin_unlock_irqrestore(&gpiommgpio->lock, flags);
272
273 /* prepare for next gpio register set */
274 mask[BIT_WORD(i)] >>= gpio_reg_size;
275 bits[BIT_WORD(i)] >>= gpio_reg_size;
276 }
277}
278
279#define GPIOMM_NGPIO 48
280static const char *gpiomm_names[GPIOMM_NGPIO] = {
281 "Port 1A0", "Port 1A1", "Port 1A2", "Port 1A3", "Port 1A4", "Port 1A5",
282 "Port 1A6", "Port 1A7", "Port 1B0", "Port 1B1", "Port 1B2", "Port 1B3",
283 "Port 1B4", "Port 1B5", "Port 1B6", "Port 1B7", "Port 1C0", "Port 1C1",
284 "Port 1C2", "Port 1C3", "Port 1C4", "Port 1C5", "Port 1C6", "Port 1C7",
285 "Port 2A0", "Port 2A1", "Port 2A2", "Port 2A3", "Port 2A4", "Port 2A5",
286 "Port 2A6", "Port 2A7", "Port 2B0", "Port 2B1", "Port 2B2", "Port 2B3",
287 "Port 2B4", "Port 2B5", "Port 2B6", "Port 2B7", "Port 2C0", "Port 2C1",
288 "Port 2C2", "Port 2C3", "Port 2C4", "Port 2C5", "Port 2C6", "Port 2C7",
289};
290
291static int gpiomm_probe(struct device *dev, unsigned int id)
292{
293 struct gpiomm_gpio *gpiommgpio;
294 const char *const name = dev_name(dev);
295 int err;
296
297 gpiommgpio = devm_kzalloc(dev, sizeof(*gpiommgpio), GFP_KERNEL);
298 if (!gpiommgpio)
299 return -ENOMEM;
300
301 if (!devm_request_region(dev, base[id], GPIOMM_EXTENT, name)) {
302 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
303 base[id], base[id] + GPIOMM_EXTENT);
304 return -EBUSY;
305 }
306
307 gpiommgpio->chip.label = name;
308 gpiommgpio->chip.parent = dev;
309 gpiommgpio->chip.owner = THIS_MODULE;
310 gpiommgpio->chip.base = -1;
311 gpiommgpio->chip.ngpio = GPIOMM_NGPIO;
312 gpiommgpio->chip.names = gpiomm_names;
313 gpiommgpio->chip.get_direction = gpiomm_gpio_get_direction;
314 gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input;
315 gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
316 gpiommgpio->chip.get = gpiomm_gpio_get;
317 gpiommgpio->chip.get_multiple = gpiomm_gpio_get_multiple;
318 gpiommgpio->chip.set = gpiomm_gpio_set;
319 gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple;
320 gpiommgpio->base = base[id];
321
322 spin_lock_init(&gpiommgpio->lock);
323
324 err = devm_gpiochip_add_data(dev, &gpiommgpio->chip, gpiommgpio);
325 if (err) {
326 dev_err(dev, "GPIO registering failed (%d)\n", err);
327 return err;
328 }
329
330 /* initialize all GPIO as output */
331 outb(0x80, base[id] + 3);
332 outb(0x00, base[id]);
333 outb(0x00, base[id] + 1);
334 outb(0x00, base[id] + 2);
335 outb(0x80, base[id] + 7);
336 outb(0x00, base[id] + 4);
337 outb(0x00, base[id] + 5);
338 outb(0x00, base[id] + 6);
339
340 return 0;
341}
342
343static struct isa_driver gpiomm_driver = {
344 .probe = gpiomm_probe,
345 .driver = {
346 .name = "gpio-mm"
347 },
348};
349
350module_isa_driver(gpiomm_driver, num_gpiomm);
351
352MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
353MODULE_DESCRIPTION("Diamond Systems GPIO-MM GPIO driver");
354MODULE_LICENSE("GPL v2");
355