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drivers/gpio/gpio-74x164.c
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/* * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver * * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org> * Copyright (C) 2010 Miguel Gaio <miguel.gaio@efixo.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/mutex.h> #include <linux/spi/spi.h> #include <linux/spi/74x164.h> #include <linux/gpio.h> #include <linux/slab.h> |
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#include <linux/module.h> |
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struct gen_74x164_chip { struct spi_device *spi; struct gpio_chip gpio_chip; struct mutex lock; u8 port_config; }; |
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static struct gen_74x164_chip *gpio_to_74x164_chip(struct gpio_chip *gc) |
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{ return container_of(gc, struct gen_74x164_chip, gpio_chip); } static int __gen_74x164_write_config(struct gen_74x164_chip *chip) { return spi_write(chip->spi, &chip->port_config, sizeof(chip->port_config)); } |
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static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) { |
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struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); |
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int ret; mutex_lock(&chip->lock); ret = (chip->port_config >> offset) & 0x1; mutex_unlock(&chip->lock); return ret; } static void gen_74x164_set_value(struct gpio_chip *gc, unsigned offset, int val) { |
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struct gen_74x164_chip *chip = gpio_to_74x164_chip(gc); |
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mutex_lock(&chip->lock); if (val) chip->port_config |= (1 << offset); else chip->port_config &= ~(1 << offset); __gen_74x164_write_config(chip); mutex_unlock(&chip->lock); } |
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static int gen_74x164_direction_output(struct gpio_chip *gc, unsigned offset, int val) { gen_74x164_set_value(gc, offset, val); return 0; } |
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static int __devinit gen_74x164_probe(struct spi_device *spi) { struct gen_74x164_chip *chip; struct gen_74x164_chip_platform_data *pdata; int ret; pdata = spi->dev.platform_data; if (!pdata || !pdata->base) { dev_dbg(&spi->dev, "incorrect or missing platform data "); return -EINVAL; } /* * bits_per_word cannot be configured in platform data */ spi->bits_per_word = 8; ret = spi_setup(spi); if (ret < 0) return ret; chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; mutex_init(&chip->lock); dev_set_drvdata(&spi->dev, chip); chip->spi = spi; |
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chip->gpio_chip.label = spi->modalias; chip->gpio_chip.direction_output = gen_74x164_direction_output; |
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chip->gpio_chip.get = gen_74x164_get_value; chip->gpio_chip.set = gen_74x164_set_value; chip->gpio_chip.base = pdata->base; |
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chip->gpio_chip.ngpio = 8; |
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chip->gpio_chip.can_sleep = 1; chip->gpio_chip.dev = &spi->dev; chip->gpio_chip.owner = THIS_MODULE; ret = __gen_74x164_write_config(chip); if (ret) { dev_err(&spi->dev, "Failed writing: %d ", ret); goto exit_destroy; } ret = gpiochip_add(&chip->gpio_chip); if (ret) goto exit_destroy; return ret; exit_destroy: dev_set_drvdata(&spi->dev, NULL); mutex_destroy(&chip->lock); kfree(chip); return ret; } |
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static int __devexit gen_74x164_remove(struct spi_device *spi) |
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{ struct gen_74x164_chip *chip; int ret; chip = dev_get_drvdata(&spi->dev); if (chip == NULL) return -ENODEV; dev_set_drvdata(&spi->dev, NULL); ret = gpiochip_remove(&chip->gpio_chip); if (!ret) { mutex_destroy(&chip->lock); kfree(chip); } else dev_err(&spi->dev, "Failed to remove the GPIO controller: %d ", ret); return ret; } static struct spi_driver gen_74x164_driver = { .driver = { |
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.name = "74x164", |
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.owner = THIS_MODULE, }, .probe = gen_74x164_probe, .remove = __devexit_p(gen_74x164_remove), }; static int __init gen_74x164_init(void) { return spi_register_driver(&gen_74x164_driver); } subsys_initcall(gen_74x164_init); static void __exit gen_74x164_exit(void) { spi_unregister_driver(&gen_74x164_driver); } module_exit(gen_74x164_exit); MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>"); MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); MODULE_LICENSE("GPL v2"); |