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authoreric miao <eric.miao@marvell.com>2008-02-05 01:28:26 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 12:44:13 -0500
commit9e60fdcf0c2905d7a8fc4cb2b3711ea5c5acaae1 (patch)
treec90417ab0e2079d0355ffb553985d9a0f2348bab /drivers/gpio
parente58b9e2762a6ef99e20dba47aba21b911658541d (diff)
gpiolib: pca9539 i2c gpio expander support
This adds a new-style I2C driver with basic support for the sixteen bit PCA9539 GPIO expanders. These chips have multiple registers, push-pull output drivers, and (not supported in this patch) pin change interrupts. Board-specific code must provide "pca9539_platform_data" with each chip's "i2c_board_info". That provides the GPIO numbers to be used by that chip, and callbacks for board-specific setup/teardown logic. Derived from drivers/i2c/chips/pca9539.c (which has no current known users). This is faster and simpler; it uses 16-bit register access, and cache the OUTPUT and DIRECTION registers for fast access Signed-off-by: eric miao <eric.miao@marvell.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Jean Delvare <khali@linux-fr.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Philipp Zabel <philipp.zabel@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ben Gardner <bgardner@wabtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/Kconfig10
-rw-r--r--drivers/gpio/Makefile1
-rw-r--r--drivers/gpio/pca9539.c271
3 files changed, 282 insertions, 0 deletions
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d924a32c089a..74fac0f5c348 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -27,6 +27,16 @@ config DEBUG_GPIO
27 27
28comment "I2C GPIO expanders:" 28comment "I2C GPIO expanders:"
29 29
30config GPIO_PCA9539
31 tristate "PCA9539 16-bit I/O port"
32 depends on I2C
33 help
34 Say yes here to support the PCA9539 16-bit I/O port. These
35 parts are made by NXP and TI.
36
37 This driver can also be built as a module. If so, the module
38 will be called pca9539.
39
30config GPIO_PCF857X 40config GPIO_PCF857X
31 tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders" 41 tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders"
32 depends on I2C 42 depends on I2C
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a1fd877ac527..470ecd6aa778 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -5,4 +5,5 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
5obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o 5obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o
6 6
7obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o 7obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
8obj-$(CONFIG_GPIO_PCA9539) += pca9539.o
8obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o 9obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o
diff --git a/drivers/gpio/pca9539.c b/drivers/gpio/pca9539.c
new file mode 100644
index 000000000000..3e85c92a7d59
--- /dev/null
+++ b/drivers/gpio/pca9539.c
@@ -0,0 +1,271 @@
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>
17#include <linux/i2c/pca9539.h>
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
29struct 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 */
41static 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
49static 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
63static 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
80static 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
111static 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, &reg_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
131static 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
151static 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
169static 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
217out_failed:
218 kfree(chip);
219 return ret;
220}
221
222static 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
249static struct i2c_driver pca9539_driver = {
250 .driver = {
251 .name = "pca9539",
252 },
253 .probe = pca9539_probe,
254 .remove = pca9539_remove,
255};
256
257static int __init pca9539_init(void)
258{
259 return i2c_add_driver(&pca9539_driver);
260}
261module_init(pca9539_init);
262
263static void __exit pca9539_exit(void)
264{
265 i2c_del_driver(&pca9539_driver);
266}
267module_exit(pca9539_exit);
268
269MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
270MODULE_DESCRIPTION("GPIO expander driver for PCA9539");
271MODULE_LICENSE("GPL");