From ead6db084392349ad33323b1bb2916058dd7e82b Mon Sep 17 00:00:00 2001 From: Miguel Gaio Date: Wed, 27 Oct 2010 15:33:18 -0700 Subject: gpio: add support for 74x164 serial-in/parallel-out 8-bit shift register Add support for generic 74x164 serial-in/parallel-out 8-bits shift register. This driver can be used as a GPIO output expander. [akpm@linux-foundation.org: remove unused local `refresh'] Signed-off-by: Miguel Gaio Signed-off-by: Juhos Gabor Signed-off-by: Florian Fainelli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/gpio/74x164.c | 182 +++++++++++++++++++++++++++++++++++++++++++++ drivers/gpio/Kconfig | 8 ++ drivers/gpio/Makefile | 1 + include/linux/spi/74x164.h | 11 +++ 4 files changed, 202 insertions(+) create mode 100644 drivers/gpio/74x164.c create mode 100644 include/linux/spi/74x164.h diff --git a/drivers/gpio/74x164.c b/drivers/gpio/74x164.c new file mode 100644 index 000000000000..d91ff4c282e9 --- /dev/null +++ b/drivers/gpio/74x164.c @@ -0,0 +1,182 @@ +/* + * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver + * + * Copyright (C) 2010 Gabor Juhos + * Copyright (C) 2010 Miguel Gaio + * + * 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 +#include +#include +#include +#include +#include + +#define GEN_74X164_GPIO_COUNT 8 + + +struct gen_74x164_chip { + struct spi_device *spi; + struct gpio_chip gpio_chip; + struct mutex lock; + u8 port_config; +}; + +static void gen_74x164_set_value(struct gpio_chip *, unsigned, int); + +static struct gen_74x164_chip *gpio_to_chip(struct gpio_chip *gc) +{ + 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)); +} + +static int gen_74x164_direction_output(struct gpio_chip *gc, + unsigned offset, int val) +{ + gen_74x164_set_value(gc, offset, val); + return 0; +} + +static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) +{ + struct gen_74x164_chip *chip = gpio_to_chip(gc); + 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) +{ + struct gen_74x164_chip *chip = gpio_to_chip(gc); + + 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); +} + +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\n"); + 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; + + chip->gpio_chip.label = GEN_74X164_DRIVER_NAME, + chip->gpio_chip.direction_output = gen_74x164_direction_output; + chip->gpio_chip.get = gen_74x164_get_value; + chip->gpio_chip.set = gen_74x164_set_value; + chip->gpio_chip.base = pdata->base; + chip->gpio_chip.ngpio = GEN_74X164_GPIO_COUNT; + 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\n", 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; +} + +static int gen_74x164_remove(struct spi_device *spi) +{ + 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\n", + ret); + + return ret; +} + +static struct spi_driver gen_74x164_driver = { + .driver = { + .name = GEN_74X164_DRIVER_NAME, + .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 "); +MODULE_AUTHOR("Miguel Gaio "); +MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index e47ef94be379..bc7b0fca6415 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -344,6 +344,14 @@ config GPIO_MC33880 SPI driver for Freescale MC33880 high-side/low-side switch. This provides GPIO interface supporting inputs and outputs. +config GPIO_74X164 + tristate "74x164 serial-in/parallel-out 8-bits shift register" + depends on SPI_MASTER + help + Platform driver for 74x164 compatible serial-in/parallel-out + 8-outputs shift registers. This driver can be used to provide access + to more gpio outputs. + comment "AC97 GPIO expanders:" config GPIO_UCB1400 diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 3ff0651fd173..0c23a4dd45e5 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_GPIO_MAX7301) += max7301.o obj-$(CONFIG_GPIO_MAX732X) += max732x.o obj-$(CONFIG_GPIO_MC33880) += mc33880.o obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o +obj-$(CONFIG_GPIO_74X164) += 74x164.o obj-$(CONFIG_GPIO_PCA953X) += pca953x.o obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o obj-$(CONFIG_GPIO_PL061) += pl061.o diff --git a/include/linux/spi/74x164.h b/include/linux/spi/74x164.h new file mode 100644 index 000000000000..d85c52f294a0 --- /dev/null +++ b/include/linux/spi/74x164.h @@ -0,0 +1,11 @@ +#ifndef LINUX_SPI_74X164_H +#define LINUX_SPI_74X164_H + +#define GEN_74X164_DRIVER_NAME "74x164" + +struct gen_74x164_chip_platform_data { + /* number assigned to the first GPIO */ + unsigned base; +}; + +#endif -- cgit v1.2.3