On Tue, Dec 07, 2010 at 09:51:58AM -0500, Cyril Chemparathy wrote:
> 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 <cy...@ti.com>
> ---
> drivers/gpio/Kconfig | 10 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/ti-ssp-gpio.c | 206
> ++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mfd/ti_ssp.h | 4 +
> 4 files changed, 221 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..387970e
> --- /dev/null
> +++ b/drivers/gpio/ti-ssp-gpio.c
> @@ -0,0 +1,206 @@
> +/*
> + * 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 direction_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 direction_out(struct gpio_chip *chip, unsigned gpio_num, int val)
All of these static functions still need to have the driver-specific
prefix to avoid any possibility of collisions in the global namespace.
I haven't checked the rest of the patches, but this comment does stand
for the whole series.
>From the rest of this file it looks like ti_ssp_gpio_ is the
appropriate prefix here.
Otherwise this patch looks okay.
g.
> +{
> + 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 value_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 value_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 = 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_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 <cy...@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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> linux-arm-ker...@lists.infradead.org
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