183 строки
4.1 KiB
C
183 строки
4.1 KiB
C
/*
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* 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
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*
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* Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
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* Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/mutex.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/74x164.h>
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#include <linux/gpio.h>
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#include <linux/slab.h>
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#define GEN_74X164_GPIO_COUNT 8
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struct gen_74x164_chip {
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struct spi_device *spi;
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struct gpio_chip gpio_chip;
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struct mutex lock;
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u8 port_config;
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};
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static void gen_74x164_set_value(struct gpio_chip *, unsigned, int);
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static struct gen_74x164_chip *gpio_to_chip(struct gpio_chip *gc)
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{
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return container_of(gc, struct gen_74x164_chip, gpio_chip);
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}
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static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
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{
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return spi_write(chip->spi,
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&chip->port_config, sizeof(chip->port_config));
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}
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static int gen_74x164_direction_output(struct gpio_chip *gc,
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unsigned offset, int val)
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{
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gen_74x164_set_value(gc, offset, val);
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return 0;
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}
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static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset)
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{
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struct gen_74x164_chip *chip = gpio_to_chip(gc);
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int ret;
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mutex_lock(&chip->lock);
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ret = (chip->port_config >> offset) & 0x1;
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mutex_unlock(&chip->lock);
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return ret;
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}
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static void gen_74x164_set_value(struct gpio_chip *gc,
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unsigned offset, int val)
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{
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struct gen_74x164_chip *chip = gpio_to_chip(gc);
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mutex_lock(&chip->lock);
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if (val)
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chip->port_config |= (1 << offset);
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else
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chip->port_config &= ~(1 << offset);
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__gen_74x164_write_config(chip);
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mutex_unlock(&chip->lock);
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}
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static int __devinit gen_74x164_probe(struct spi_device *spi)
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{
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struct gen_74x164_chip *chip;
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struct gen_74x164_chip_platform_data *pdata;
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int ret;
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pdata = spi->dev.platform_data;
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if (!pdata || !pdata->base) {
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dev_dbg(&spi->dev, "incorrect or missing platform data\n");
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return -EINVAL;
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}
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/*
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* bits_per_word cannot be configured in platform data
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*/
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spi->bits_per_word = 8;
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ret = spi_setup(spi);
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if (ret < 0)
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return ret;
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chip = kzalloc(sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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mutex_init(&chip->lock);
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dev_set_drvdata(&spi->dev, chip);
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chip->spi = spi;
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chip->gpio_chip.label = GEN_74X164_DRIVER_NAME,
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chip->gpio_chip.direction_output = gen_74x164_direction_output;
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chip->gpio_chip.get = gen_74x164_get_value;
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chip->gpio_chip.set = gen_74x164_set_value;
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chip->gpio_chip.base = pdata->base;
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chip->gpio_chip.ngpio = GEN_74X164_GPIO_COUNT;
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chip->gpio_chip.can_sleep = 1;
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chip->gpio_chip.dev = &spi->dev;
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chip->gpio_chip.owner = THIS_MODULE;
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ret = __gen_74x164_write_config(chip);
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if (ret) {
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dev_err(&spi->dev, "Failed writing: %d\n", ret);
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goto exit_destroy;
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}
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ret = gpiochip_add(&chip->gpio_chip);
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if (ret)
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goto exit_destroy;
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return ret;
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exit_destroy:
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dev_set_drvdata(&spi->dev, NULL);
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mutex_destroy(&chip->lock);
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kfree(chip);
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return ret;
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}
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static int __devexit gen_74x164_remove(struct spi_device *spi)
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{
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struct gen_74x164_chip *chip;
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int ret;
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chip = dev_get_drvdata(&spi->dev);
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if (chip == NULL)
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return -ENODEV;
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dev_set_drvdata(&spi->dev, NULL);
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ret = gpiochip_remove(&chip->gpio_chip);
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if (!ret) {
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mutex_destroy(&chip->lock);
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kfree(chip);
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} else
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dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
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ret);
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return ret;
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}
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static struct spi_driver gen_74x164_driver = {
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.driver = {
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.name = GEN_74X164_DRIVER_NAME,
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.owner = THIS_MODULE,
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},
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.probe = gen_74x164_probe,
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.remove = __devexit_p(gen_74x164_remove),
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};
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static int __init gen_74x164_init(void)
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{
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return spi_register_driver(&gen_74x164_driver);
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}
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subsys_initcall(gen_74x164_init);
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static void __exit gen_74x164_exit(void)
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{
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spi_unregister_driver(&gen_74x164_driver);
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}
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module_exit(gen_74x164_exit);
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MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
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MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
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MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register");
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MODULE_LICENSE("GPL v2");
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