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1/*
2 * GPIO interface for IT87xx Super I/O chips
3 *
4 * Author: Diego Elio Pettenò <flameeyes@flameeyes.eu>
5 *
6 * Based on it87_wdt.c by Oliver Schuster
7 * gpio-it8761e.c by Denis Turischev
8 * gpio-stmpe.c by Rabin Vincent
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License 2 as published
12 * by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; see the file COPYING. If not, write to
21 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/init.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/io.h>
30#include <linux/errno.h>
31#include <linux/ioport.h>
32#include <linux/slab.h>
33#include <linux/gpio.h>
34
35/* Chip Id numbers */
36#define NO_DEV_ID 0xffff
37#define IT8728_ID 0x8728
38#define IT8732_ID 0x8732
39#define IT8761_ID 0x8761
40
41/* IO Ports */
42#define REG 0x2e
43#define VAL 0x2f
44
45/* Logical device Numbers LDN */
46#define GPIO 0x07
47
48/* Configuration Registers and Functions */
49#define LDNREG 0x07
50#define CHIPID 0x20
51#define CHIPREV 0x22
52
53/**
54 * struct it87_gpio - it87-specific GPIO chip
55 * @chip the underlying gpio_chip structure
56 * @lock a lock to avoid races between operations
57 * @io_base base address for gpio ports
58 * @io_size size of the port rage starting from io_base.
59 * @output_base Super I/O register address for Output Enable register
60 * @simple_base Super I/O 'Simple I/O' Enable register
61 * @simple_size Super IO 'Simple I/O' Enable register size; this is
62 * required because IT87xx chips might only provide Simple I/O
63 * switches on a subset of lines, whereas the others keep the
64 * same status all time.
65 */
66struct it87_gpio {
67 struct gpio_chip chip;
68 spinlock_t lock;
69 u16 io_base;
70 u16 io_size;
71 u8 output_base;
72 u8 simple_base;
73 u8 simple_size;
74};
75
76static struct it87_gpio it87_gpio_chip = {
77 .lock = __SPIN_LOCK_UNLOCKED(it87_gpio_chip.lock),
78};
79
80/* Superio chip access functions; copied from wdt_it87 */
81
82static inline int superio_enter(void)
83{
84 /*
85 * Try to reserve REG and REG + 1 for exclusive access.
86 */
87 if (!request_muxed_region(REG, 2, KBUILD_MODNAME))
88 return -EBUSY;
89
90 outb(0x87, REG);
91 outb(0x01, REG);
92 outb(0x55, REG);
93 outb(0x55, REG);
94 return 0;
95}
96
97static inline void superio_exit(void)
98{
99 outb(0x02, REG);
100 outb(0x02, VAL);
101 release_region(REG, 2);
102}
103
104static inline void superio_select(int ldn)
105{
106 outb(LDNREG, REG);
107 outb(ldn, VAL);
108}
109
110static inline int superio_inb(int reg)
111{
112 outb(reg, REG);
113 return inb(VAL);
114}
115
116static inline void superio_outb(int val, int reg)
117{
118 outb(reg, REG);
119 outb(val, VAL);
120}
121
122static inline int superio_inw(int reg)
123{
124 int val;
125
126 outb(reg++, REG);
127 val = inb(VAL) << 8;
128 outb(reg, REG);
129 val |= inb(VAL);
130 return val;
131}
132
133static inline void superio_outw(int val, int reg)
134{
135 outb(reg++, REG);
136 outb(val >> 8, VAL);
137 outb(reg, REG);
138 outb(val, VAL);
139}
140
141static inline void superio_set_mask(int mask, int reg)
142{
143 u8 curr_val = superio_inb(reg);
144 u8 new_val = curr_val | mask;
145
146 if (curr_val != new_val)
147 superio_outb(new_val, reg);
148}
149
150static inline void superio_clear_mask(int mask, int reg)
151{
152 u8 curr_val = superio_inb(reg);
153 u8 new_val = curr_val & ~mask;
154
155 if (curr_val != new_val)
156 superio_outb(new_val, reg);
157}
158
159static int it87_gpio_request(struct gpio_chip *chip, unsigned gpio_num)
160{
161 u8 mask, group;
162 int rc = 0;
163 struct it87_gpio *it87_gpio = gpiochip_get_data(chip);
164
165 mask = 1 << (gpio_num % 8);
166 group = (gpio_num / 8);
167
168 spin_lock(&it87_gpio->lock);
169
170 rc = superio_enter();
171 if (rc)
172 goto exit;
173
174 /* not all the IT87xx chips support Simple I/O and not all of
175 * them allow all the lines to be set/unset to Simple I/O.
176 */
177 if (group < it87_gpio->simple_size)
178 superio_set_mask(mask, group + it87_gpio->simple_base);
179
180 /* clear output enable, setting the pin to input, as all the
181 * newly-exported GPIO interfaces are set to input.
182 */
183 superio_clear_mask(mask, group + it87_gpio->output_base);
184
185 superio_exit();
186
187exit:
188 spin_unlock(&it87_gpio->lock);
189 return rc;
190}
191
192static int it87_gpio_get(struct gpio_chip *chip, unsigned gpio_num)
193{
194 u16 reg;
195 u8 mask;
196 struct it87_gpio *it87_gpio = gpiochip_get_data(chip);
197
198 mask = 1 << (gpio_num % 8);
199 reg = (gpio_num / 8) + it87_gpio->io_base;
200
201 return !!(inb(reg) & mask);
202}
203
204static int it87_gpio_direction_in(struct gpio_chip *chip, unsigned gpio_num)
205{
206 u8 mask, group;
207 int rc = 0;
208 struct it87_gpio *it87_gpio = gpiochip_get_data(chip);
209
210 mask = 1 << (gpio_num % 8);
211 group = (gpio_num / 8);
212
213 spin_lock(&it87_gpio->lock);
214
215 rc = superio_enter();
216 if (rc)
217 goto exit;
218
219 /* clear the output enable bit */
220 superio_clear_mask(mask, group + it87_gpio->output_base);
221
222 superio_exit();
223
224exit:
225 spin_unlock(&it87_gpio->lock);
226 return rc;
227}
228
229static void it87_gpio_set(struct gpio_chip *chip,
230 unsigned gpio_num, int val)
231{
232 u8 mask, curr_vals;
233 u16 reg;
234 struct it87_gpio *it87_gpio = gpiochip_get_data(chip);
235
236 mask = 1 << (gpio_num % 8);
237 reg = (gpio_num / 8) + it87_gpio->io_base;
238
239 curr_vals = inb(reg);
240 if (val)
241 outb(curr_vals | mask, reg);
242 else
243 outb(curr_vals & ~mask, reg);
244}
245
246static int it87_gpio_direction_out(struct gpio_chip *chip,
247 unsigned gpio_num, int val)
248{
249 u8 mask, group;
250 int rc = 0;
251 struct it87_gpio *it87_gpio = gpiochip_get_data(chip);
252
253 mask = 1 << (gpio_num % 8);
254 group = (gpio_num / 8);
255
256 spin_lock(&it87_gpio->lock);
257
258 rc = superio_enter();
259 if (rc)
260 goto exit;
261
262 /* set the output enable bit */
263 superio_set_mask(mask, group + it87_gpio->output_base);
264
265 it87_gpio_set(chip, gpio_num, val);
266
267 superio_exit();
268
269exit:
270 spin_unlock(&it87_gpio->lock);
271 return rc;
272}
273
274static struct gpio_chip it87_template_chip = {
275 .label = KBUILD_MODNAME,
276 .owner = THIS_MODULE,
277 .request = it87_gpio_request,
278 .get = it87_gpio_get,
279 .direction_input = it87_gpio_direction_in,
280 .set = it87_gpio_set,
281 .direction_output = it87_gpio_direction_out,
282 .base = -1
283};
284
285static int __init it87_gpio_init(void)
286{
287 int rc = 0, i;
288 u16 chip_type;
289 u8 chip_rev, gpio_ba_reg;
290 char *labels, **labels_table;
291
292 struct it87_gpio *it87_gpio = &it87_gpio_chip;
293
294 rc = superio_enter();
295 if (rc)
296 return rc;
297
298 chip_type = superio_inw(CHIPID);
299 chip_rev = superio_inb(CHIPREV) & 0x0f;
300 superio_exit();
301
302 it87_gpio->chip = it87_template_chip;
303
304 switch (chip_type) {
305 case IT8728_ID:
306 case IT8732_ID:
307 gpio_ba_reg = 0x62;
308 it87_gpio->io_size = 8;
309 it87_gpio->output_base = 0xc8;
310 it87_gpio->simple_base = 0xc0;
311 it87_gpio->simple_size = 5;
312 it87_gpio->chip.ngpio = 64;
313 break;
314 case IT8761_ID:
315 gpio_ba_reg = 0x60;
316 it87_gpio->io_size = 4;
317 it87_gpio->output_base = 0xf0;
318 it87_gpio->simple_size = 0;
319 it87_gpio->chip.ngpio = 16;
320 break;
321 case NO_DEV_ID:
322 pr_err("no device\n");
323 return -ENODEV;
324 default:
325 pr_err("Unknown Chip found, Chip %04x Revision %x\n",
326 chip_type, chip_rev);
327 return -ENODEV;
328 }
329
330 rc = superio_enter();
331 if (rc)
332 return rc;
333
334 superio_select(GPIO);
335
336 /* fetch GPIO base address */
337 it87_gpio->io_base = superio_inw(gpio_ba_reg);
338
339 superio_exit();
340
341 pr_info("Found Chip IT%04x rev %x. %u GPIO lines starting at %04xh\n",
342 chip_type, chip_rev, it87_gpio->chip.ngpio,
343 it87_gpio->io_base);
344
345 if (!request_region(it87_gpio->io_base, it87_gpio->io_size,
346 KBUILD_MODNAME))
347 return -EBUSY;
348
349 /* Set up aliases for the GPIO connection.
350 *
351 * ITE documentation for recent chips such as the IT8728F
352 * refers to the GPIO lines as GPxy, with a coordinates system
353 * where x is the GPIO group (starting from 1) and y is the
354 * bit within the group.
355 *
356 * By creating these aliases, we make it easier to understand
357 * to which GPIO pin we're referring to.
358 */
359 labels = kcalloc(it87_gpio->chip.ngpio, sizeof("it87_gpXY"),
360 GFP_KERNEL);
361 labels_table = kcalloc(it87_gpio->chip.ngpio, sizeof(const char *),
362 GFP_KERNEL);
363
364 if (!labels || !labels_table) {
365 rc = -ENOMEM;
366 goto labels_free;
367 }
368
369 for (i = 0; i < it87_gpio->chip.ngpio; i++) {
370 char *label = &labels[i * sizeof("it87_gpXY")];
371
372 sprintf(label, "it87_gp%u%u", 1+(i/8), i%8);
373 labels_table[i] = label;
374 }
375
376 it87_gpio->chip.names = (const char *const*)labels_table;
377
378 rc = gpiochip_add_data(&it87_gpio->chip, it87_gpio);
379 if (rc)
380 goto labels_free;
381
382 return 0;
383
384labels_free:
385 kfree(labels_table);
386 kfree(labels);
387 release_region(it87_gpio->io_base, it87_gpio->io_size);
388 return rc;
389}
390
391static void __exit it87_gpio_exit(void)
392{
393 struct it87_gpio *it87_gpio = &it87_gpio_chip;
394
395 gpiochip_remove(&it87_gpio->chip);
396 release_region(it87_gpio->io_base, it87_gpio->io_size);
397 kfree(it87_gpio->chip.names[0]);
398 kfree(it87_gpio->chip.names);
399}
400
401module_init(it87_gpio_init);
402module_exit(it87_gpio_exit);
403
404MODULE_AUTHOR("Diego Elio Pettenò <flameeyes@flameeyes.eu>");
405MODULE_DESCRIPTION("GPIO interface for IT87xx Super I/O chips");
406MODULE_LICENSE("GPL");