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9e60fdcf | 1 | /* |
2 | * pca9539.c - 16-bit I/O port with interrupt and reset | |
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> | |
d1c057e3 | 17 | #include <linux/i2c/pca953x.h> |
9e60fdcf | 18 | |
19 | #include <asm/gpio.h> | |
20 | ||
21 | ||
22 | #define NR_PCA9539_GPIOS 16 | |
23 | ||
24 | #define PCA9539_INPUT 0 | |
25 | #define PCA9539_OUTPUT 2 | |
26 | #define PCA9539_INVERT 4 | |
27 | #define PCA9539_DIRECTION 6 | |
28 | ||
29 | struct pca9539_chip { | |
30 | unsigned gpio_start; | |
31 | uint16_t reg_output; | |
32 | uint16_t reg_direction; | |
33 | ||
34 | struct i2c_client *client; | |
35 | struct gpio_chip gpio_chip; | |
36 | }; | |
37 | ||
38 | /* NOTE: we can't currently rely on fault codes to come from SMBus | |
39 | * calls, so we map all errors to EIO here and return zero otherwise. | |
40 | */ | |
41 | static int pca9539_write_reg(struct pca9539_chip *chip, int reg, uint16_t val) | |
42 | { | |
43 | if (i2c_smbus_write_word_data(chip->client, reg, val) < 0) | |
44 | return -EIO; | |
45 | else | |
46 | return 0; | |
47 | } | |
48 | ||
49 | static int pca9539_read_reg(struct pca9539_chip *chip, int reg, uint16_t *val) | |
50 | { | |
51 | int ret; | |
52 | ||
53 | ret = i2c_smbus_read_word_data(chip->client, reg); | |
54 | if (ret < 0) { | |
55 | dev_err(&chip->client->dev, "failed reading register\n"); | |
56 | return -EIO; | |
57 | } | |
58 | ||
59 | *val = (uint16_t)ret; | |
60 | return 0; | |
61 | } | |
62 | ||
63 | static int pca9539_gpio_direction_input(struct gpio_chip *gc, unsigned off) | |
64 | { | |
65 | struct pca9539_chip *chip; | |
66 | uint16_t reg_val; | |
67 | int ret; | |
68 | ||
69 | chip = container_of(gc, struct pca9539_chip, gpio_chip); | |
70 | ||
71 | reg_val = chip->reg_direction | (1u << off); | |
72 | ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); | |
73 | if (ret) | |
74 | return ret; | |
75 | ||
76 | chip->reg_direction = reg_val; | |
77 | return 0; | |
78 | } | |
79 | ||
80 | static int pca9539_gpio_direction_output(struct gpio_chip *gc, | |
81 | unsigned off, int val) | |
82 | { | |
83 | struct pca9539_chip *chip; | |
84 | uint16_t reg_val; | |
85 | int ret; | |
86 | ||
87 | chip = container_of(gc, struct pca9539_chip, gpio_chip); | |
88 | ||
89 | /* set output level */ | |
90 | if (val) | |
91 | reg_val = chip->reg_output | (1u << off); | |
92 | else | |
93 | reg_val = chip->reg_output & ~(1u << off); | |
94 | ||
95 | ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); | |
96 | if (ret) | |
97 | return ret; | |
98 | ||
99 | chip->reg_output = reg_val; | |
100 | ||
101 | /* then direction */ | |
102 | reg_val = chip->reg_direction & ~(1u << off); | |
103 | ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); | |
104 | if (ret) | |
105 | return ret; | |
106 | ||
107 | chip->reg_direction = reg_val; | |
108 | return 0; | |
109 | } | |
110 | ||
111 | static int pca9539_gpio_get_value(struct gpio_chip *gc, unsigned off) | |
112 | { | |
113 | struct pca9539_chip *chip; | |
114 | uint16_t reg_val; | |
115 | int ret; | |
116 | ||
117 | chip = container_of(gc, struct pca9539_chip, gpio_chip); | |
118 | ||
119 | ret = pca9539_read_reg(chip, PCA9539_INPUT, ®_val); | |
120 | if (ret < 0) { | |
121 | /* NOTE: diagnostic already emitted; that's all we should | |
122 | * do unless gpio_*_value_cansleep() calls become different | |
123 | * from their nonsleeping siblings (and report faults). | |
124 | */ | |
125 | return 0; | |
126 | } | |
127 | ||
128 | return (reg_val & (1u << off)) ? 1 : 0; | |
129 | } | |
130 | ||
131 | static void pca9539_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) | |
132 | { | |
133 | struct pca9539_chip *chip; | |
134 | uint16_t reg_val; | |
135 | int ret; | |
136 | ||
137 | chip = container_of(gc, struct pca9539_chip, gpio_chip); | |
138 | ||
139 | if (val) | |
140 | reg_val = chip->reg_output | (1u << off); | |
141 | else | |
142 | reg_val = chip->reg_output & ~(1u << off); | |
143 | ||
144 | ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); | |
145 | if (ret) | |
146 | return; | |
147 | ||
148 | chip->reg_output = reg_val; | |
149 | } | |
150 | ||
151 | static int pca9539_init_gpio(struct pca9539_chip *chip) | |
152 | { | |
153 | struct gpio_chip *gc; | |
154 | ||
155 | gc = &chip->gpio_chip; | |
156 | ||
157 | gc->direction_input = pca9539_gpio_direction_input; | |
158 | gc->direction_output = pca9539_gpio_direction_output; | |
159 | gc->get = pca9539_gpio_get_value; | |
160 | gc->set = pca9539_gpio_set_value; | |
161 | ||
162 | gc->base = chip->gpio_start; | |
163 | gc->ngpio = NR_PCA9539_GPIOS; | |
164 | gc->label = "pca9539"; | |
165 | ||
166 | return gpiochip_add(gc); | |
167 | } | |
168 | ||
169 | static int __devinit pca9539_probe(struct i2c_client *client) | |
170 | { | |
171 | struct pca9539_platform_data *pdata; | |
172 | struct pca9539_chip *chip; | |
173 | int ret; | |
174 | ||
175 | pdata = client->dev.platform_data; | |
176 | if (pdata == NULL) | |
177 | return -ENODEV; | |
178 | ||
179 | chip = kzalloc(sizeof(struct pca9539_chip), GFP_KERNEL); | |
180 | if (chip == NULL) | |
181 | return -ENOMEM; | |
182 | ||
183 | chip->client = client; | |
184 | ||
185 | chip->gpio_start = pdata->gpio_base; | |
186 | ||
187 | /* initialize cached registers from their original values. | |
188 | * we can't share this chip with another i2c master. | |
189 | */ | |
190 | ret = pca9539_read_reg(chip, PCA9539_OUTPUT, &chip->reg_output); | |
191 | if (ret) | |
192 | goto out_failed; | |
193 | ||
194 | ret = pca9539_read_reg(chip, PCA9539_DIRECTION, &chip->reg_direction); | |
195 | if (ret) | |
196 | goto out_failed; | |
197 | ||
198 | /* set platform specific polarity inversion */ | |
199 | ret = pca9539_write_reg(chip, PCA9539_INVERT, pdata->invert); | |
200 | if (ret) | |
201 | goto out_failed; | |
202 | ||
203 | ret = pca9539_init_gpio(chip); | |
204 | if (ret) | |
205 | goto out_failed; | |
206 | ||
207 | if (pdata->setup) { | |
208 | ret = pdata->setup(client, chip->gpio_chip.base, | |
209 | chip->gpio_chip.ngpio, pdata->context); | |
210 | if (ret < 0) | |
211 | dev_warn(&client->dev, "setup failed, %d\n", ret); | |
212 | } | |
213 | ||
214 | i2c_set_clientdata(client, chip); | |
215 | return 0; | |
216 | ||
217 | out_failed: | |
218 | kfree(chip); | |
219 | return ret; | |
220 | } | |
221 | ||
222 | static int pca9539_remove(struct i2c_client *client) | |
223 | { | |
224 | struct pca9539_platform_data *pdata = client->dev.platform_data; | |
225 | struct pca9539_chip *chip = i2c_get_clientdata(client); | |
226 | int ret = 0; | |
227 | ||
228 | if (pdata->teardown) { | |
229 | ret = pdata->teardown(client, chip->gpio_chip.base, | |
230 | chip->gpio_chip.ngpio, pdata->context); | |
231 | if (ret < 0) { | |
232 | dev_err(&client->dev, "%s failed, %d\n", | |
233 | "teardown", ret); | |
234 | return ret; | |
235 | } | |
236 | } | |
237 | ||
238 | ret = gpiochip_remove(&chip->gpio_chip); | |
239 | if (ret) { | |
240 | dev_err(&client->dev, "%s failed, %d\n", | |
241 | "gpiochip_remove()", ret); | |
242 | return ret; | |
243 | } | |
244 | ||
245 | kfree(chip); | |
246 | return 0; | |
247 | } | |
248 | ||
249 | static struct i2c_driver pca9539_driver = { | |
250 | .driver = { | |
251 | .name = "pca9539", | |
252 | }, | |
253 | .probe = pca9539_probe, | |
254 | .remove = pca9539_remove, | |
255 | }; | |
256 | ||
257 | static int __init pca9539_init(void) | |
258 | { | |
259 | return i2c_add_driver(&pca9539_driver); | |
260 | } | |
261 | module_init(pca9539_init); | |
262 | ||
263 | static void __exit pca9539_exit(void) | |
264 | { | |
265 | i2c_del_driver(&pca9539_driver); | |
266 | } | |
267 | module_exit(pca9539_exit); | |
268 | ||
269 | MODULE_AUTHOR("eric miao <eric.miao@marvell.com>"); | |
270 | MODULE_DESCRIPTION("GPIO expander driver for PCA9539"); | |
271 | MODULE_LICENSE("GPL"); |