Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
[zen-stable.git] / drivers / gpio / gpio-74x164.c
bloba31ad6f5d9106f370167f518f719f4cf2d26323a
1 /*
2 * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
4 * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/init.h>
13 #include <linux/mutex.h>
14 #include <linux/spi/spi.h>
15 #include <linux/spi/74x164.h>
16 #include <linux/gpio.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
20 struct gen_74x164_chip {
21 struct spi_device *spi;
22 struct gpio_chip gpio_chip;
23 struct mutex lock;
24 u8 port_config;
27 static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc)
29 return container_of(gc, struct gen_74x164_chip, gpio_chip);
32 static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
34 return spi_write(chip->spi,
35 &chip->port_config, sizeof(chip->port_config));
38 static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
40 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
41 int ret;
43 mutex_lock(&chip->lock);
44 ret = (chip->port_config >> offset) & 0x1;
45 mutex_unlock(&chip->lock);
47 return ret;
50 static void gen_74x164_set_value(struct gpio_chip *gc,
51 unsigned offset, int val)
53 struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc);
55 mutex_lock(&chip->lock);
56 if (val)
57 chip->port_config |= (1 << offset);
58 else
59 chip->port_config &= ~(1 << offset);
61 __gen_74x164_write_config(chip);
62 mutex_unlock(&chip->lock);
65 static int gen_74x164_direction_output(struct gpio_chip *gc,
66 unsigned offset, int val)
68 gen_74x164_set_value(gc, offset, val);
69 return 0;
72 static int __devinit gen_74x164_probe(struct spi_device *spi)
74 struct gen_74x164_chip *chip;
75 struct gen_74x164_chip_platform_data *pdata;
76 int ret;
78 pdata = spi->dev.platform_data;
79 if (!pdata || !pdata->base) {
80 dev_dbg(&spi->dev, "incorrect or missing platform data\n");
81 return -EINVAL;
85 * bits_per_word cannot be configured in platform data
87 spi->bits_per_word = 8;
89 ret = spi_setup(spi);
90 if (ret < 0)
91 return ret;
93 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
94 if (!chip)
95 return -ENOMEM;
97 mutex_init(&chip->lock);
99 dev_set_drvdata(&spi->dev, chip);
101 chip->spi = spi;
103 chip->gpio_chip.label = spi->modalias;
104 chip->gpio_chip.direction_output = gen_74x164_direction_output;
105 chip->gpio_chip.get = gen_74x164_get_value;
106 chip->gpio_chip.set = gen_74x164_set_value;
107 chip->gpio_chip.base = pdata->base;
108 chip->gpio_chip.ngpio = 8;
109 chip->gpio_chip.can_sleep = 1;
110 chip->gpio_chip.dev = &spi->dev;
111 chip->gpio_chip.owner = THIS_MODULE;
113 ret = __gen_74x164_write_config(chip);
114 if (ret) {
115 dev_err(&spi->dev, "Failed writing: %d\n", ret);
116 goto exit_destroy;
119 ret = gpiochip_add(&chip->gpio_chip);
120 if (ret)
121 goto exit_destroy;
123 return ret;
125 exit_destroy:
126 dev_set_drvdata(&spi->dev, NULL);
127 mutex_destroy(&chip->lock);
128 kfree(chip);
129 return ret;
132 static int __devexit gen_74x164_remove(struct spi_device *spi)
134 struct gen_74x164_chip *chip;
135 int ret;
137 chip = dev_get_drvdata(&spi->dev);
138 if (chip == NULL)
139 return -ENODEV;
141 dev_set_drvdata(&spi->dev, NULL);
143 ret = gpiochip_remove(&chip->gpio_chip);
144 if (!ret) {
145 mutex_destroy(&chip->lock);
146 kfree(chip);
147 } else
148 dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
149 ret);
151 return ret;
154 static struct spi_driver gen_74x164_driver = {
155 .driver = {
156 .name = "74x164",
157 .owner = THIS_MODULE,
159 .probe = gen_74x164_probe,
160 .remove = __devexit_p(gen_74x164_remove),
163 static int __init gen_74x164_init(void)
165 return spi_register_driver(&gen_74x164_driver);
167 subsys_initcall(gen_74x164_init);
169 static void __exit gen_74x164_exit(void)
171 spi_unregister_driver(&gen_74x164_driver);
173 module_exit(gen_74x164_exit);
175 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
176 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
177 MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
178 MODULE_LICENSE("GPL v2");