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Commit d22fcde0 authored by Guenter Roeck's avatar Guenter Roeck Committed by Linus Walleij
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gpio: Kontron PLD gpio driver 



Add gpio support for the on-board PLD found on some Kontron embedded modules.

Originally-from: Michael Brunner <michael.brunner@kontron.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarKevin Strasser <kevin.strasser@linux.intel.com>
Acked-by: default avatarDarren Hart <dvhart@linux.intel.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent a3d88c92

drivers/gpio/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -691,6 +691,18 @@ config GPIO_UCB1400 
	  This enables support for the Philips UCB1400 GPIO pins.

	  The UCB1400 is an AC97 audio codec.



comment "LPC GPIO expanders:"



config GPIO_KEMPLD

	tristate "Kontron ETX / COMexpress GPIO"

	depends on MFD_KEMPLD

	help

	  This enables support for the PLD GPIO interface on some Kontron ETX

	  and COMexpress (ETXexpress) modules.



	  This driver can also be built as a module. If so, the module will be

	  called gpio-kempld.



comment "MODULbus GPIO expanders:"



config GPIO_JANZ_TTL

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o 
obj-$(CONFIG_GPIO_ICH)		+= gpio-ich.o

obj-$(CONFIG_GPIO_IT8761E)	+= gpio-it8761e.o

obj-$(CONFIG_GPIO_JANZ_TTL)	+= gpio-janz-ttl.o

obj-$(CONFIG_GPIO_KEMPLD)	+= gpio-kempld.o

obj-$(CONFIG_ARCH_KS8695)	+= gpio-ks8695.o

obj-$(CONFIG_GPIO_LANGWELL)	+= gpio-langwell.o

obj-$(CONFIG_ARCH_LPC32XX)	+= gpio-lpc32xx.o

drivers/gpio/gpio-kempld.c

0 → 100644
+225 −0
Original line number Diff line number Diff line 
/*

 * Kontron PLD GPIO driver

 *

 * Copyright (c) 2010-2013 Kontron Europe GmbH

 * Author: Michael Brunner <michael.brunner@kontron.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License 2 as published

 * by the Free Software Foundation.

 *

 * 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.

 */



#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/bitops.h>

#include <linux/errno.h>

#include <linux/platform_device.h>

#include <linux/gpio.h>

#include <linux/mfd/kempld.h>



#define KEMPLD_GPIO_MAX_NUM		16

#define KEMPLD_GPIO_MASK(x)		(1 << ((x) % 8))

#define KEMPLD_GPIO_DIR_NUM(x)		(0x40 + (x) / 8)

#define KEMPLD_GPIO_LVL_NUM(x)		(0x42 + (x) / 8)

#define KEMPLD_GPIO_EVT_LVL_EDGE	0x46

#define KEMPLD_GPIO_IEN			0x4A



struct kempld_gpio_data {

	struct gpio_chip		chip;

	struct kempld_device_data	*pld;

};



/*

 * Set or clear GPIO bit

 * kempld_get_mutex must be called prior to calling this function.

 */

static void kempld_gpio_bitop(struct kempld_device_data *pld,

			      u8 reg, u8 bit, u8 val)

{

	u8 status;



	status = kempld_read8(pld, reg);

	if (val)

		status |= (1 << bit);

	else

		status &= ~(1 << bit);

	kempld_write8(pld, reg, status);

}



static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)

{

	u8 status;



	kempld_get_mutex(pld);

	status = kempld_read8(pld, reg);

	kempld_release_mutex(pld);



	return !!(status & (1 << bit));

}



static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)

{

	struct kempld_gpio_data *gpio

		= container_of(chip, struct kempld_gpio_data, chip);

	struct kempld_device_data *pld = gpio->pld;



	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset),

				   KEMPLD_GPIO_MASK(offset));

}



static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)

{

	struct kempld_gpio_data *gpio

		= container_of(chip, struct kempld_gpio_data, chip);

	struct kempld_device_data *pld = gpio->pld;



	kempld_get_mutex(pld);

	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),

			  KEMPLD_GPIO_MASK(offset), value);

	kempld_release_mutex(pld);

}



static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)

{

	struct kempld_gpio_data *gpio

		= container_of(chip, struct kempld_gpio_data, chip);

	struct kempld_device_data *pld = gpio->pld;



	kempld_get_mutex(pld);

	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),

			  KEMPLD_GPIO_MASK(offset), 0);

	kempld_release_mutex(pld);



	return 0;

}



static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,

					int value)

{

	struct kempld_gpio_data *gpio

		= container_of(chip, struct kempld_gpio_data, chip);

	struct kempld_device_data *pld = gpio->pld;



	kempld_get_mutex(pld);

	kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset),

			  KEMPLD_GPIO_MASK(offset), value);

	kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset),

			  KEMPLD_GPIO_MASK(offset), 1);

	kempld_release_mutex(pld);



	return 0;

}



static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)

{

	struct kempld_gpio_data *gpio

		= container_of(chip, struct kempld_gpio_data, chip);

	struct kempld_device_data *pld = gpio->pld;



	return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset),

				   KEMPLD_GPIO_MASK(offset));

}



static int kempld_gpio_pincount(struct kempld_device_data *pld)

{

	u16 evt, evt_back;



	kempld_get_mutex(pld);



	/* Backup event register as it might be already initialized */

	evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);

	/* Clear event register */

	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);

	/* Read back event register */

	evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);

	/* Restore event register */

	kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);



	kempld_release_mutex(pld);



	return evt ? __ffs(evt) : 16;

}



static int kempld_gpio_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct kempld_device_data *pld = dev_get_drvdata(dev->parent);

	struct kempld_platform_data *pdata = pld->dev->platform_data;

	struct kempld_gpio_data *gpio;

	struct gpio_chip *chip;

	int ret;



	if (pld->info.spec_major < 2) {

		dev_err(dev,

			"Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");

		return -ENODEV;

	}



	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);

	if (gpio == NULL)

		return -ENOMEM;



	gpio->pld = pld;



	platform_set_drvdata(pdev, gpio);



	chip = &gpio->chip;

	chip->label = "gpio-kempld";

	chip->owner = THIS_MODULE;

	chip->dev = dev;

	chip->can_sleep = 1;

	if (pdata && pdata->gpio_base)

		chip->base = pdata->gpio_base;

	else

		chip->base = -1;

	chip->direction_input = kempld_gpio_direction_input;

	chip->direction_output = kempld_gpio_direction_output;

	chip->get_direction = kempld_gpio_get_direction;

	chip->get = kempld_gpio_get;

	chip->set = kempld_gpio_set;

	chip->ngpio = kempld_gpio_pincount(pld);

	if (chip->ngpio == 0) {

		dev_err(dev, "No GPIO pins detected\n");

		return -ENODEV;

	}



	ret = gpiochip_add(chip);

	if (ret) {

		dev_err(dev, "Could not register GPIO chip\n");

		return ret;

	}



	dev_info(dev, "GPIO functionality initialized with %d pins\n",

		 chip->ngpio);



	return 0;

}



static int kempld_gpio_remove(struct platform_device *pdev)

{

	struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);



	return gpiochip_remove(&gpio->chip);

}



static struct platform_driver kempld_gpio_driver = {

	.driver = {

		.name = "gpio-kempld",

		.owner = THIS_MODULE,

	},

	.probe		= kempld_gpio_probe,

	.remove		= kempld_gpio_remove,

};



module_platform_driver(kempld_gpio_driver);



MODULE_DESCRIPTION("KEM PLD GPIO Driver");

MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:gpio-kempld");