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    Subject[PATCH v8 03/11] gpio: add ti-ssp gpio driver
    Date
    TI's SSP controller pins can be directly read and written to behave like a
    GPIO. This patch adds a GPIO driver that exposes such functionality.

    Signed-off-by: Cyril Chemparathy <cyril@ti.com>
    ---
    drivers/gpio/Kconfig | 10 ++
    drivers/gpio/Makefile | 1 +
    drivers/gpio/ti-ssp-gpio.c | 207 ++++++++++++++++++++++++++++++++++++++++++++
    include/linux/mfd/ti_ssp.h | 4 +
    4 files changed, 222 insertions(+), 0 deletions(-)
    create mode 100644 drivers/gpio/ti-ssp-gpio.c

    diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
    index 3143ac7..05bbe4c 100644
    --- a/drivers/gpio/Kconfig
    +++ b/drivers/gpio/Kconfig
    @@ -128,6 +128,16 @@ config GPIO_VX855
    additional drivers must be enabled in order to use the
    functionality of the device.

    +config GPIO_TI_SSP
    + tristate "TI Sequencer Serial Port - GPIO Support"
    + depends on MFD_TI_SSP
    + help
    + Say yes here to support a GPIO interface on TI SSP port pins.
    + Each SSP port translates into 4 GPIOs.
    +
    + This driver can also be built as a module. If so, the module
    + will be called ti-ssp-gpio.
    +
    comment "I2C GPIO expanders:"

    config GPIO_MAX7300
    diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
    index bdf3dde..0e2a844 100644
    --- a/drivers/gpio/Makefile
    +++ b/drivers/gpio/Makefile
    @@ -26,6 +26,7 @@ obj-$(CONFIG_GPIO_PL061) += pl061.o
    obj-$(CONFIG_GPIO_STMPE) += stmpe-gpio.o
    obj-$(CONFIG_GPIO_TC35892) += tc35892-gpio.o
    obj-$(CONFIG_GPIO_TIMBERDALE) += timbgpio.o
    +obj-$(CONFIG_GPIO_TI_SSP) += ti-ssp-gpio.o
    obj-$(CONFIG_GPIO_TWL4030) += twl4030-gpio.o
    obj-$(CONFIG_GPIO_UCB1400) += ucb1400_gpio.o
    obj-$(CONFIG_GPIO_XILINX) += xilinx_gpio.o
    diff --git a/drivers/gpio/ti-ssp-gpio.c b/drivers/gpio/ti-ssp-gpio.c
    new file mode 100644
    index 0000000..edc3142
    --- /dev/null
    +++ b/drivers/gpio/ti-ssp-gpio.c
    @@ -0,0 +1,207 @@
    +/*
    + * Sequencer Serial Port (SSP) based virtual GPIO driver
    + *
    + * Copyright (C) 2010 Texas Instruments Inc
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    + */
    +
    +#include <linux/init.h>
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/io.h>
    +#include <linux/err.h>
    +#include <linux/slab.h>
    +#include <linux/gpio.h>
    +#include <linux/platform_device.h>
    +#include <linux/mfd/ti_ssp.h>
    +
    +struct ti_ssp_gpio_chip {
    + struct gpio_chip chip;
    + struct device *dev;
    + spinlock_t lock;
    + u8 out;
    + u32 iosel;
    +};
    +
    +#define to_ssp_gpio_chip(c) container_of(c, struct ti_ssp_gpio_chip, chip)
    +
    +static int ti_ssp_gpio_dir_in(struct gpio_chip *chip, unsigned gpio_num)
    +{
    + struct ti_ssp_gpio_chip *gpio = to_ssp_gpio_chip(chip);
    + int error = 0;
    +
    + spin_lock(&gpio->lock);
    +
    + gpio->iosel &= ~SSP_PIN_MASK(gpio_num);
    + gpio->iosel |= SSP_PIN_SEL(gpio_num, SSP_IN);
    +
    + error = ti_ssp_set_iosel(gpio->dev, gpio->iosel);
    +
    + spin_unlock(&gpio->lock);
    +
    + return error;
    +}
    +
    +static int ti_ssp_gpio_dir_out(struct gpio_chip *chip, unsigned gpio_num,
    + int val)
    +{
    + struct ti_ssp_gpio_chip *gpio = to_ssp_gpio_chip(chip);
    + int error;
    +
    + spin_lock(&gpio->lock);
    +
    + gpio->iosel &= ~SSP_PIN_MASK(gpio_num);
    + gpio->iosel |= SSP_PIN_SEL(gpio_num, SSP_OUT);
    +
    + error = ti_ssp_set_iosel(gpio->dev, gpio->iosel);
    +
    + if (error < 0)
    + goto error;
    +
    + if (val)
    + gpio->out |= BIT(gpio_num);
    + else
    + gpio->out &= ~BIT(gpio_num);
    +
    + error = ti_ssp_raw_write(gpio->dev, gpio->out);
    +
    +error:
    + spin_unlock(&gpio->lock);
    + return error;
    +}
    +
    +static int ti_ssp_gpio_get(struct gpio_chip *chip, unsigned gpio_num)
    +{
    + struct ti_ssp_gpio_chip *gpio = to_ssp_gpio_chip(chip);
    + int ret;
    +
    + spin_lock(&gpio->lock);
    +
    + ret = ti_ssp_raw_read(gpio->dev);
    + if (ret >= 0)
    + ret = !!(ret & BIT(gpio_num));
    +
    + spin_unlock(&gpio->lock);
    + return ret;
    +}
    +
    +static void ti_ssp_gpio_set(struct gpio_chip *chip, unsigned gpio_num, int val)
    +{
    + struct ti_ssp_gpio_chip *gpio = to_ssp_gpio_chip(chip);
    +
    + spin_lock(&gpio->lock);
    +
    + if (val)
    + gpio->out |= BIT(gpio_num);
    + else
    + gpio->out &= ~BIT(gpio_num);
    +
    + ti_ssp_raw_write(gpio->dev, gpio->out);
    +
    + spin_unlock(&gpio->lock);
    +}
    +
    +static int __devinit ti_ssp_gpio_probe(struct platform_device *pdev)
    +{
    + const struct ti_ssp_gpio_data *pdata = pdev->dev.platform_data;
    + struct device *dev = &pdev->dev;
    + struct ti_ssp_gpio_chip *gpio;
    + int error;
    +
    + if (!pdata) {
    + dev_err(dev, "platform data not found\n");
    + return -EINVAL;
    + }
    +
    + gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
    + if (!gpio) {
    + dev_err(dev, "cannot allocate driver data\n");
    + return -ENOMEM;
    + }
    +
    + gpio->dev = dev;
    + gpio->iosel = SSP_PIN_SEL(0, SSP_IN) | SSP_PIN_SEL(1, SSP_IN) |
    + SSP_PIN_SEL(2, SSP_IN) | SSP_PIN_SEL(3, SSP_IN);
    + error = ti_ssp_set_iosel(gpio->dev, gpio->iosel);
    + if (error < 0) {
    + dev_err(dev, "gpio io setup failed (%d)\n", error);
    + goto error;
    + }
    +
    + spin_lock_init(&gpio->lock);
    + platform_set_drvdata(pdev, gpio);
    +
    + gpio->chip.base = pdata->start;
    + gpio->chip.ngpio = 4;
    + gpio->chip.dev = &pdev->dev;
    + gpio->chip.label = "ti_ssp_gpio";
    + gpio->chip.owner = THIS_MODULE;
    + gpio->chip.get = ti_ssp_gpio_get;
    + gpio->chip.set = ti_ssp_gpio_set;
    + gpio->chip.direction_input = ti_ssp_gpio_dir_in;
    + gpio->chip.direction_output = ti_ssp_gpio_dir_out;
    +
    + error = gpiochip_add(&gpio->chip);
    + if (error < 0) {
    + dev_err(dev, "gpio chip registration failed (%d)\n", error);
    + goto error;
    + }
    +
    + dev_info(dev, "ssp gpio interface registered\n");
    + return 0;
    +
    +error:
    + kfree(gpio);
    + return error;
    +}
    +
    +static int __devexit ti_ssp_gpio_remove(struct platform_device *pdev)
    +{
    + struct ti_ssp_gpio_chip *gpio = platform_get_drvdata(pdev);
    + int error;
    +
    + error = gpiochip_remove(&gpio->chip);
    + if (error < 0)
    + return error;
    + kfree(gpio);
    + return 0;
    +}
    +
    +static struct platform_driver ti_ssp_gpio_driver = {
    + .probe = ti_ssp_gpio_probe,
    + .remove = __devexit_p(ti_ssp_gpio_remove),
    + .driver = {
    + .name = "ti-ssp-gpio",
    + .owner = THIS_MODULE,
    + },
    +};
    +
    +static int __init ti_ssp_gpio_init(void)
    +{
    + return platform_driver_register(&ti_ssp_gpio_driver);
    +}
    +module_init(ti_ssp_gpio_init);
    +
    +static void __exit ti_ssp_gpio_exit(void)
    +{
    + platform_driver_unregister(&ti_ssp_gpio_driver);
    +}
    +module_exit(ti_ssp_gpio_exit);
    +
    +MODULE_DESCRIPTION("GPIO interface for TI-SSP");
    +MODULE_AUTHOR("Cyril Chemparathy <cyril@ti.com>");
    +MODULE_LICENSE("GPL");
    +MODULE_ALIAS("platform:ti-ssp-gpio");
    diff --git a/include/linux/mfd/ti_ssp.h b/include/linux/mfd/ti_ssp.h
    index dbb4b43..10c65bb 100644
    --- a/include/linux/mfd/ti_ssp.h
    +++ b/include/linux/mfd/ti_ssp.h
    @@ -38,6 +38,10 @@ struct ti_ssp_spi_data {
    void (*select)(int cs);
    };

    +struct ti_ssp_gpio_data {
    + int start;
    +};
    +
    /*
    * Sequencer port IO pin configuration bits. These do not correlate 1-1 with
    * the hardware. The iosel field in the port data combines iosel1 and iosel2,
    --
    1.7.1


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