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Eric Miaobbcd6d52008-07-25 01:46:14 -07001/*
2 * max732x.c - I2C Port Expander with 8/16 I/O
3 *
4 * Copyright (C) 2007 Marvell International Ltd.
5 * Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
6 * Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
7 *
8 * Derived from drivers/gpio/pca953x.c
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 as published by
12 * the Free Software Foundation; version 2 of the License.
13 */
14
15#include <linux/module.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19#include <linux/gpio.h>
20
21#include <linux/i2c.h>
22#include <linux/i2c/max732x.h>
23
24
25/*
26 * Each port of MAX732x (including MAX7319) falls into one of the
27 * following three types:
28 *
29 * - Push Pull Output
30 * - Input
31 * - Open Drain I/O
32 *
33 * designated by 'O', 'I' and 'P' individually according to MAXIM's
34 * datasheets.
35 *
36 * There are two groups of I/O ports, each group usually includes
37 * up to 8 I/O ports, and is accessed by a specific I2C address:
38 *
39 * - Group A : by I2C address 0b'110xxxx
40 * - Group B : by I2C address 0b'101xxxx
41 *
42 * where 'xxxx' is decided by the connections of pin AD2/AD0. The
43 * address used also affects the initial state of output signals.
44 *
45 * Within each group of ports, there are five known combinations of
46 * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
47 * the detailed organization of these ports.
48 *
49 * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
50 * and GPIOs from GROUP_A are numbered before those from GROUP_B
51 * (if there are two groups).
52 *
53 * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
54 * they are not supported by this driver.
55 */
56
57#define PORT_NONE 0x0 /* '/' No Port */
58#define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */
59#define PORT_INPUT 0x2 /* 'I' Input Only */
60#define PORT_OPENDRAIN 0x3 /* 'P' Open-Drain, I/O */
61
62#define IO_4I4O 0x5AA5 /* O7 O6 I5 I4 I3 I2 O1 O0 */
63#define IO_4P4O 0x5FF5 /* O7 O6 P5 P4 P3 P2 O1 O0 */
64#define IO_8I 0xAAAA /* I7 I6 I5 I4 I3 I2 I1 I0 */
65#define IO_8P 0xFFFF /* P7 P6 P5 P4 P3 P2 P1 P0 */
66#define IO_8O 0x5555 /* O7 O6 O5 O4 O3 O2 O1 O0 */
67
68#define GROUP_A(x) ((x) & 0xffff) /* I2C Addr: 0b'110xxxx */
69#define GROUP_B(x) ((x) << 16) /* I2C Addr: 0b'101xxxx */
70
71static const struct i2c_device_id max732x_id[] = {
72 { "max7319", GROUP_A(IO_8I) },
73 { "max7320", GROUP_B(IO_8O) },
74 { "max7321", GROUP_A(IO_8P) },
75 { "max7322", GROUP_A(IO_4I4O) },
76 { "max7323", GROUP_A(IO_4P4O) },
77 { "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
78 { "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
79 { "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
80 { "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
81 { },
82};
83MODULE_DEVICE_TABLE(i2c, max732x_id);
84
85struct max732x_chip {
86 struct gpio_chip gpio_chip;
87
88 struct i2c_client *client; /* "main" client */
89 struct i2c_client *client_dummy;
90 struct i2c_client *client_group_a;
91 struct i2c_client *client_group_b;
92
93 unsigned int mask_group_a;
94 unsigned int dir_input;
95 unsigned int dir_output;
96
97 struct mutex lock;
98 uint8_t reg_out[2];
99};
100
101static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
102{
103 struct i2c_client *client;
104 int ret;
105
106 client = group_a ? chip->client_group_a : chip->client_group_b;
107 ret = i2c_smbus_write_byte(client, val);
108 if (ret < 0) {
109 dev_err(&client->dev, "failed writing\n");
110 return ret;
111 }
112
113 return 0;
114}
115
116static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
117{
118 struct i2c_client *client;
119 int ret;
120
121 client = group_a ? chip->client_group_a : chip->client_group_b;
122 ret = i2c_smbus_read_byte(client);
123 if (ret < 0) {
124 dev_err(&client->dev, "failed reading\n");
125 return ret;
126 }
127
128 *val = (uint8_t)ret;
129 return 0;
130}
131
132static inline int is_group_a(struct max732x_chip *chip, unsigned off)
133{
134 return (1u << off) & chip->mask_group_a;
135}
136
137static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
138{
139 struct max732x_chip *chip;
140 uint8_t reg_val;
141 int ret;
142
143 chip = container_of(gc, struct max732x_chip, gpio_chip);
144
145 ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
146 if (ret < 0)
147 return 0;
148
149 return reg_val & (1u << (off & 0x7));
150}
151
152static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
153{
154 struct max732x_chip *chip;
155 uint8_t reg_out, mask = 1u << (off & 0x7);
156 int ret;
157
158 chip = container_of(gc, struct max732x_chip, gpio_chip);
159
160 mutex_lock(&chip->lock);
161
162 reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
163 reg_out = (val) ? reg_out | mask : reg_out & ~mask;
164
165 ret = max732x_write(chip, is_group_a(chip, off), reg_out);
166 if (ret < 0)
167 goto out;
168
169 /* update the shadow register then */
170 if (off > 7)
171 chip->reg_out[1] = reg_out;
172 else
173 chip->reg_out[0] = reg_out;
174out:
175 mutex_unlock(&chip->lock);
176}
177
178static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
179{
180 struct max732x_chip *chip;
181 unsigned int mask = 1u << off;
182
183 chip = container_of(gc, struct max732x_chip, gpio_chip);
184
185 if ((mask & chip->dir_input) == 0) {
186 dev_dbg(&chip->client->dev, "%s port %d is output only\n",
187 chip->client->name, off);
188 return -EACCES;
189 }
190
191 return 0;
192}
193
194static int max732x_gpio_direction_output(struct gpio_chip *gc,
195 unsigned off, int val)
196{
197 struct max732x_chip *chip;
198 unsigned int mask = 1u << off;
199
200 chip = container_of(gc, struct max732x_chip, gpio_chip);
201
202 if ((mask & chip->dir_output) == 0) {
203 dev_dbg(&chip->client->dev, "%s port %d is input only\n",
204 chip->client->name, off);
205 return -EACCES;
206 }
207
208 max732x_gpio_set_value(gc, off, val);
209 return 0;
210}
211
212static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
213 const struct i2c_device_id *id,
214 unsigned gpio_start)
215{
216 struct gpio_chip *gc = &chip->gpio_chip;
217 uint32_t id_data = id->driver_data;
218 int i, port = 0;
219
220 for (i = 0; i < 16; i++, id_data >>= 2) {
221 unsigned int mask = 1 << port;
222
223 switch (id_data & 0x3) {
224 case PORT_OUTPUT:
225 chip->dir_output |= mask;
226 break;
227 case PORT_INPUT:
228 chip->dir_input |= mask;
229 break;
230 case PORT_OPENDRAIN:
231 chip->dir_output |= mask;
232 chip->dir_input |= mask;
233 break;
234 default:
235 continue;
236 }
237
238 if (i < 8)
239 chip->mask_group_a |= mask;
240 port++;
241 }
242
243 if (chip->dir_input)
244 gc->direction_input = max732x_gpio_direction_input;
245 if (chip->dir_output) {
246 gc->direction_output = max732x_gpio_direction_output;
247 gc->set = max732x_gpio_set_value;
248 }
249 gc->get = max732x_gpio_get_value;
250 gc->can_sleep = 1;
251
252 gc->base = gpio_start;
253 gc->ngpio = port;
254 gc->label = chip->client->name;
255 gc->owner = THIS_MODULE;
256
257 return port;
258}
259
260static int __devinit max732x_probe(struct i2c_client *client,
261 const struct i2c_device_id *id)
262{
263 struct max732x_platform_data *pdata;
264 struct max732x_chip *chip;
265 struct i2c_client *c;
266 uint16_t addr_a, addr_b;
267 int ret, nr_port;
268
269 pdata = client->dev.platform_data;
270 if (pdata == NULL)
271 return -ENODEV;
272
273 chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
274 if (chip == NULL)
275 return -ENOMEM;
276 chip->client = client;
277
278 nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
279
280 addr_a = (client->addr & 0x0f) | 0x60;
281 addr_b = (client->addr & 0x0f) | 0x50;
282
283 switch (client->addr & 0x70) {
284 case 0x60:
285 chip->client_group_a = client;
286 if (nr_port > 7) {
287 c = i2c_new_dummy(client->adapter, addr_b);
288 chip->client_group_b = chip->client_dummy = c;
289 }
290 break;
291 case 0x50:
292 chip->client_group_b = client;
293 if (nr_port > 7) {
294 c = i2c_new_dummy(client->adapter, addr_a);
295 chip->client_group_a = chip->client_dummy = c;
296 }
297 break;
298 default:
299 dev_err(&client->dev, "invalid I2C address specified %02x\n",
300 client->addr);
301 ret = -EINVAL;
302 goto out_failed;
303 }
304
305 mutex_init(&chip->lock);
306
307 max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
308 if (nr_port > 7)
309 max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);
310
311 ret = gpiochip_add(&chip->gpio_chip);
312 if (ret)
313 goto out_failed;
314
315 if (pdata->setup) {
316 ret = pdata->setup(client, chip->gpio_chip.base,
317 chip->gpio_chip.ngpio, pdata->context);
318 if (ret < 0)
319 dev_warn(&client->dev, "setup failed, %d\n", ret);
320 }
321
322 i2c_set_clientdata(client, chip);
323 return 0;
324
325out_failed:
326 kfree(chip);
327 return ret;
328}
329
330static int __devexit max732x_remove(struct i2c_client *client)
331{
332 struct max732x_platform_data *pdata = client->dev.platform_data;
333 struct max732x_chip *chip = i2c_get_clientdata(client);
334 int ret;
335
336 if (pdata->teardown) {
337 ret = pdata->teardown(client, chip->gpio_chip.base,
338 chip->gpio_chip.ngpio, pdata->context);
339 if (ret < 0) {
340 dev_err(&client->dev, "%s failed, %d\n",
341 "teardown", ret);
342 return ret;
343 }
344 }
345
346 ret = gpiochip_remove(&chip->gpio_chip);
347 if (ret) {
348 dev_err(&client->dev, "%s failed, %d\n",
349 "gpiochip_remove()", ret);
350 return ret;
351 }
352
353 /* unregister any dummy i2c_client */
354 if (chip->client_dummy)
355 i2c_unregister_device(chip->client_dummy);
356
357 kfree(chip);
358 return 0;
359}
360
361static struct i2c_driver max732x_driver = {
362 .driver = {
363 .name = "max732x",
364 .owner = THIS_MODULE,
365 },
366 .probe = max732x_probe,
367 .remove = __devexit_p(max732x_remove),
368 .id_table = max732x_id,
369};
370
371static int __init max732x_init(void)
372{
373 return i2c_add_driver(&max732x_driver);
374}
David Brownell2f8d1192008-10-15 22:03:13 -0700375/* register after i2c postcore initcall and before
376 * subsys initcalls that may rely on these GPIOs
377 */
378subsys_initcall(max732x_init);
Eric Miaobbcd6d52008-07-25 01:46:14 -0700379
380static void __exit max732x_exit(void)
381{
382 i2c_del_driver(&max732x_driver);
383}
384module_exit(max732x_exit);
385
386MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
387MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
388MODULE_LICENSE("GPL");