Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg...
[linux-2.6] / drivers / gpio / pca953x.c
1 /*
2  *  pca953x.c - 4/8/16 bit I/O ports
3  *
4  *  Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
5  *  Copyright (C) 2007 Marvell International Ltd.
6  *
7  *  Derived from drivers/i2c/chips/pca9539.c
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; version 2 of the License.
12  */
13
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/i2c.h>
17 #include <linux/i2c/pca953x.h>
18
19 #include <asm/gpio.h>
20
21 #define PCA953X_INPUT          0
22 #define PCA953X_OUTPUT         1
23 #define PCA953X_INVERT         2
24 #define PCA953X_DIRECTION      3
25
26 /* This is temporary - in 2.6.26 i2c_driver_data should replace it. */
27 struct pca953x_desc {
28         char            name[I2C_NAME_SIZE];
29         unsigned long   driver_data;
30 };
31
32 static const struct pca953x_desc pca953x_descs[] = {
33         { "pca9534", 8, },
34         { "pca9535", 16, },
35         { "pca9536", 4, },
36         { "pca9537", 4, },
37         { "pca9538", 8, },
38         { "pca9539", 16, },
39         /* REVISIT several pca955x parts should work here too */
40 };
41
42 struct pca953x_chip {
43         unsigned gpio_start;
44         uint16_t reg_output;
45         uint16_t reg_direction;
46
47         struct i2c_client *client;
48         struct gpio_chip gpio_chip;
49 };
50
51 /* NOTE:  we can't currently rely on fault codes to come from SMBus
52  * calls, so we map all errors to EIO here and return zero otherwise.
53  */
54 static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
55 {
56         int ret;
57
58         if (chip->gpio_chip.ngpio <= 8)
59                 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
60         else
61                 ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);
62
63         if (ret < 0) {
64                 dev_err(&chip->client->dev, "failed writing register\n");
65                 return -EIO;
66         }
67
68         return 0;
69 }
70
71 static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
72 {
73         int ret;
74
75         if (chip->gpio_chip.ngpio <= 8)
76                 ret = i2c_smbus_read_byte_data(chip->client, reg);
77         else
78                 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
79
80         if (ret < 0) {
81                 dev_err(&chip->client->dev, "failed reading register\n");
82                 return -EIO;
83         }
84
85         *val = (uint16_t)ret;
86         return 0;
87 }
88
89 static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
90 {
91         struct pca953x_chip *chip;
92         uint16_t reg_val;
93         int ret;
94
95         chip = container_of(gc, struct pca953x_chip, gpio_chip);
96
97         reg_val = chip->reg_direction | (1u << off);
98         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
99         if (ret)
100                 return ret;
101
102         chip->reg_direction = reg_val;
103         return 0;
104 }
105
106 static int pca953x_gpio_direction_output(struct gpio_chip *gc,
107                 unsigned off, int val)
108 {
109         struct pca953x_chip *chip;
110         uint16_t reg_val;
111         int ret;
112
113         chip = container_of(gc, struct pca953x_chip, gpio_chip);
114
115         /* set output level */
116         if (val)
117                 reg_val = chip->reg_output | (1u << off);
118         else
119                 reg_val = chip->reg_output & ~(1u << off);
120
121         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
122         if (ret)
123                 return ret;
124
125         chip->reg_output = reg_val;
126
127         /* then direction */
128         reg_val = chip->reg_direction & ~(1u << off);
129         ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
130         if (ret)
131                 return ret;
132
133         chip->reg_direction = reg_val;
134         return 0;
135 }
136
137 static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
138 {
139         struct pca953x_chip *chip;
140         uint16_t reg_val;
141         int ret;
142
143         chip = container_of(gc, struct pca953x_chip, gpio_chip);
144
145         ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
146         if (ret < 0) {
147                 /* NOTE:  diagnostic already emitted; that's all we should
148                  * do unless gpio_*_value_cansleep() calls become different
149                  * from their nonsleeping siblings (and report faults).
150                  */
151                 return 0;
152         }
153
154         return (reg_val & (1u << off)) ? 1 : 0;
155 }
156
157 static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
158 {
159         struct pca953x_chip *chip;
160         uint16_t reg_val;
161         int ret;
162
163         chip = container_of(gc, struct pca953x_chip, gpio_chip);
164
165         if (val)
166                 reg_val = chip->reg_output | (1u << off);
167         else
168                 reg_val = chip->reg_output & ~(1u << off);
169
170         ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
171         if (ret)
172                 return;
173
174         chip->reg_output = reg_val;
175 }
176
177 static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
178 {
179         struct gpio_chip *gc;
180
181         gc = &chip->gpio_chip;
182
183         gc->direction_input  = pca953x_gpio_direction_input;
184         gc->direction_output = pca953x_gpio_direction_output;
185         gc->get = pca953x_gpio_get_value;
186         gc->set = pca953x_gpio_set_value;
187         gc->can_sleep = 1;
188
189         gc->base = chip->gpio_start;
190         gc->ngpio = gpios;
191         gc->label = chip->client->name;
192         gc->owner = THIS_MODULE;
193 }
194
195 static int __devinit pca953x_probe(struct i2c_client *client)
196 {
197         struct pca953x_platform_data *pdata;
198         struct pca953x_chip *chip;
199         int ret, i;
200         const struct pca953x_desc *id = NULL;
201
202         pdata = client->dev.platform_data;
203         if (pdata == NULL)
204                 return -ENODEV;
205
206         /* this loop vanishes when we get i2c_device_id */
207         for (i = 0; i < ARRAY_SIZE(pca953x_descs); i++)
208                 if (!strcmp(pca953x_descs[i].name, client->name)) {
209                         id = pca953x_descs + i;
210                         break;
211                 }
212         if (!id)
213                 return -ENODEV;
214
215         chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
216         if (chip == NULL)
217                 return -ENOMEM;
218
219         chip->client = client;
220
221         chip->gpio_start = pdata->gpio_base;
222
223         /* initialize cached registers from their original values.
224          * we can't share this chip with another i2c master.
225          */
226         pca953x_setup_gpio(chip, id->driver_data);
227
228         ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
229         if (ret)
230                 goto out_failed;
231
232         ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
233         if (ret)
234                 goto out_failed;
235
236         /* set platform specific polarity inversion */
237         ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
238         if (ret)
239                 goto out_failed;
240
241
242         ret = gpiochip_add(&chip->gpio_chip);
243         if (ret)
244                 goto out_failed;
245
246         if (pdata->setup) {
247                 ret = pdata->setup(client, chip->gpio_chip.base,
248                                 chip->gpio_chip.ngpio, pdata->context);
249                 if (ret < 0)
250                         dev_warn(&client->dev, "setup failed, %d\n", ret);
251         }
252
253         i2c_set_clientdata(client, chip);
254         return 0;
255
256 out_failed:
257         kfree(chip);
258         return ret;
259 }
260
261 static int pca953x_remove(struct i2c_client *client)
262 {
263         struct pca953x_platform_data *pdata = client->dev.platform_data;
264         struct pca953x_chip *chip = i2c_get_clientdata(client);
265         int ret = 0;
266
267         if (pdata->teardown) {
268                 ret = pdata->teardown(client, chip->gpio_chip.base,
269                                 chip->gpio_chip.ngpio, pdata->context);
270                 if (ret < 0) {
271                         dev_err(&client->dev, "%s failed, %d\n",
272                                         "teardown", ret);
273                         return ret;
274                 }
275         }
276
277         ret = gpiochip_remove(&chip->gpio_chip);
278         if (ret) {
279                 dev_err(&client->dev, "%s failed, %d\n",
280                                 "gpiochip_remove()", ret);
281                 return ret;
282         }
283
284         kfree(chip);
285         return 0;
286 }
287
288 static struct i2c_driver pca953x_driver = {
289         .driver = {
290                 .name   = "pca953x",
291         },
292         .probe          = pca953x_probe,
293         .remove         = pca953x_remove,
294 };
295
296 static int __init pca953x_init(void)
297 {
298         return i2c_add_driver(&pca953x_driver);
299 }
300 module_init(pca953x_init);
301
302 static void __exit pca953x_exit(void)
303 {
304         i2c_del_driver(&pca953x_driver);
305 }
306 module_exit(pca953x_exit);
307
308 MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
309 MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
310 MODULE_LICENSE("GPL");