1 files changed, 177 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c
new file mode 100644
index 000000000000..7fb60b6bf523
--- /dev/null
+++ b/drivers/gpio/gpio-74x164.c
@@ -0,0 +1,177 @@
+/*
+ *  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>
+
+struct gen_74x164_chip {
+        struct spi_device       *spi;
+        struct gpio_chip        gpio_chip;
+        struct mutex            lock;
+        u8                      port_config;
+};
+
+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_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 gen_74x164_direction_output(struct gpio_chip *gc,
+                unsigned offset, int val)
+{
+        gen_74x164_set_value(gc, offset, val);
+        return 0;
+}
+
+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 = spi->modalias;
+        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 = 8;
+        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 __devexit 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           = "74x164",
+                .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");