Re: [PATCH v8 03/11] gpio: add ti-ssp gpio driver

[Grant Likely <grant.likely@secretlab.ca>]

On Mon, Feb 28, 2011 at 06:04:32PM +0530, Nori, Sekhar wrote:
> Hi Grant,
> 
> On Wed, Jan 19, 2011 at 00:51:37, Chemparathy, Cyril 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.
> 
> Can you please review and ack the GPIO part of this
> series too?
> 
> I see that you have already acked the SPI part of this work.

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

Sorry for the delay on this.  I can take it through my tree if you
like.  It's a new driver, so I don't have any concerns about taking it
now even though the merge window is already open..

g.

> 
> Thanks,
> Sekhar
> 
> > 
> > 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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