On Mon, Oct 18, 2010 at 03:25:18PM -0400, Cyril Chemparathy wrote:
> This patch adds a GPIO driver based on TI's SSP device.  This driver does not
> support GPIO-IRQs.
> 
> Signed-off-by: Cyril Chemparathy <cy...@ti.com>

Acked-by: Grant Likely <grant.lik...@secretlab.ca>

> ---
>  arch/arm/mach-davinci/include/mach/ti_ssp.h |    4 +
>  drivers/gpio/Kconfig                        |   10 ++
>  drivers/gpio/Makefile                       |    1 +
>  drivers/gpio/ti-ssp-gpio.c                  |  200 
> +++++++++++++++++++++++++++
>  4 files changed, 215 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/gpio/ti-ssp-gpio.c
> 
> diff --git a/arch/arm/mach-davinci/include/mach/ti_ssp.h 
> b/arch/arm/mach-davinci/include/mach/ti_ssp.h
> index 63c88fe..21f1429 100644
> --- a/arch/arm/mach-davinci/include/mach/ti_ssp.h
> +++ b/arch/arm/mach-davinci/include/mach/ti_ssp.h
> @@ -39,6 +39,10 @@ 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,
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 510aa20..e400761 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -111,6 +111,16 @@ config GPIO_SCH
>         This driver can also be built as a module. If so, the module
>         will be called sch-gpio.
>  
> +config GPIO_TI_SSP
> +     tristate "TI SSP Controller GPIO Driver"
> +     depends on GPIOLIB && TI_SSP
> +     help
> +       Say yes here to support a virtual GPIO interface on TI SSP ports.
> +       Each SSP port translates into 4 GPIOs, with no IRQ support.
> +
> +       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 fc6019d..98b4551 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -23,6 +23,7 @@ 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..c046713
> --- /dev/null
> +++ b/drivers/gpio/ti-ssp-gpio.c
> @@ -0,0 +1,200 @@
> +/*
> + * 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 <mach/ti_ssp.h>
> +
> +struct ti_ssp_gpio {
> +     struct gpio_chip                chip;
> +#define chip2gpio(chip)      container_of(chip, struct ti_ssp_gpio, chip)
> +     struct device                   *dev;
> +     spinlock_t                      lock;
> +     u8                              out;
> +     u32                             iosel;
> +};
> +
> +static int direction_in(struct gpio_chip *chip, unsigned gpio_num)
> +{
> +     struct ti_ssp_gpio *gpio = chip2gpio(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 direction_out(struct gpio_chip *chip, unsigned gpio_num, int val)
> +{
> +     struct ti_ssp_gpio *gpio = chip2gpio(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 value_get(struct gpio_chip *chip, unsigned gpio_num)
> +{
> +     struct ti_ssp_gpio *gpio = chip2gpio(chip);
> +     int ret;
> +
> +     spin_lock(&gpio->lock);
> +
> +     ret = ti_ssp_raw_read(gpio->dev);
> +     if (ret >= 0)
> +             ret = (ret & BIT(gpio_num)) ? 1 : 0;
> +
> +     spin_unlock(&gpio->lock);
> +     return ret;
> +}
> +
> +static void value_set(struct gpio_chip *chip, unsigned gpio_num, int val)
> +{
> +     struct ti_ssp_gpio *gpio = chip2gpio(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 *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);
> +     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   = value_get;
> +     gpio->chip.set   = value_set;
> +     gpio->chip.direction_input  = direction_in;
> +     gpio->chip.direction_output = direction_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 *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);
> +}
> +subsys_initcall(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 <cy...@ti.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ti-ssp-gpio");
> -- 
> 1.7.0.4
> 

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