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.
Acked-by: Grant Likely <grant.lik...@secretlab.ca> Signed-off-by: Cyril Chemparathy <cy...@ti.com> --- 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 bff8ef6..8fed5ab 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 ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ spi-devel-general mailing list spi-devel-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/spi-devel-general