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Commit 99ea2626 authored by Daniel Drake's avatar Daniel Drake Committed by Samuel Ortiz
Browse files

gpio: Add VIA VX855 GPIO driver 



This is needed for supporting the upcoming VX855 camera and OLPC DCON
drivers, as well as the advanced viafb features on non-OLPC hardware
based on this chip.

Based on earlier work by Harald Welte.

Signed-off-by: default avatarDaniel Drake <dsd@laptop.org>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 375fc77b

drivers/gpio/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -116,6 +116,18 @@ config GPIO_SCH 
	  This driver can also be built as a module. If so, the module

	  will be called sch-gpio.



config GPIO_VX855

	tristate "VIA VX855/VX875 GPIO"

	depends on GPIOLIB

	select MFD_CORE

	select MFD_VX855

	help

	  Support access to the VX855/VX875 GPIO lines through the gpio library.



	  This driver provides common support for accessing the device,

	  additional drivers must be enabled in order to use the

	  functionality of the device.



comment "I2C GPIO expanders:"



config GPIO_MAX7300

drivers/gpio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -40,3 +40,4 @@ obj-$(CONFIG_GPIO_SCH) += sch_gpio.o 
obj-$(CONFIG_GPIO_RDC321X)	+= rdc321x-gpio.o

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

obj-$(CONFIG_GPIO_SX150X)	+= sx150x.o

obj-$(CONFIG_GPIO_VX855)	+= vx855_gpio.o

drivers/gpio/vx855_gpio.c

0 → 100644
+332 −0
Original line number Diff line number Diff line 
/*

 * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO

 *

 * Copyright (C) 2009 VIA Technologies, Inc.

 * Copyright (C) 2010 One Laptop per Child

 * Author: Harald Welte <HaraldWelte@viatech.com>

 * All rights reserved.

 *

 * 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/kernel.h>

#include <linux/module.h>

#include <linux/gpio.h>

#include <linux/device.h>

#include <linux/platform_device.h>

#include <linux/pci.h>

#include <linux/io.h>



#define MODULE_NAME "vx855_gpio"



/* The VX855 south bridge has the following GPIO pins:

 *	GPI 0...13	General Purpose Input

 *	GPO 0...12	General Purpose Output

 *	GPIO 0...14	General Purpose I/O (Open-Drain)

 */



#define NR_VX855_GPI	14

#define NR_VX855_GPO	13

#define NR_VX855_GPIO	15



#define NR_VX855_GPInO	(NR_VX855_GPI + NR_VX855_GPO)

#define NR_VX855_GP	(NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)



struct vx855_gpio {

	struct gpio_chip gpio;

	spinlock_t lock;

	u32 io_gpi;

	u32 io_gpo;

	bool gpi_reserved;

	bool gpo_reserved;

};



/* resolve a GPIx into the corresponding bit position */

static inline u_int32_t gpi_i_bit(int i)

{

	if (i < 10)

		return 1 << i;

	else

		return 1 << (i + 14);

}



static inline u_int32_t gpo_o_bit(int i)

{

	if (i < 11)

		return 1 << i;

	else

		return 1 << (i + 14);

}



static inline u_int32_t gpio_i_bit(int i)

{

	if (i < 14)

		return 1 << (i + 10);

	else

		return 1 << (i + 14);

}



static inline u_int32_t gpio_o_bit(int i)

{

	if (i < 14)

		return 1 << (i + 11);

	else

		return 1 << (i + 13);

}



/* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:

 * 0..13	GPI 0..13

 * 14..26	GPO 0..12

 * 27..41	GPIO 0..14

 */



static int vx855gpio_direction_input(struct gpio_chip *gpio,

				     unsigned int nr)

{

	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);

	unsigned long flags;

	u_int32_t reg_out;



	/* Real GPI bits are always in input direction */

	if (nr < NR_VX855_GPI)

		return 0;



	/* Real GPO bits cannot be put in output direction */

	if (nr < NR_VX855_GPInO)

		return -EINVAL;



	/* Open Drain GPIO have to be set to one */

	spin_lock_irqsave(&vg->lock, flags);

	reg_out = inl(vg->io_gpo);

	reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);

	outl(reg_out, vg->io_gpo);

	spin_unlock_irqrestore(&vg->lock, flags);



	return 0;

}



static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)

{

	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);

	u_int32_t reg_in;

	int ret = 0;



	if (nr < NR_VX855_GPI) {

		reg_in = inl(vg->io_gpi);

		if (reg_in & gpi_i_bit(nr))

			ret = 1;

	} else if (nr < NR_VX855_GPInO) {

		/* GPO don't have an input bit, we need to read it

		 * back from the output register */

		reg_in = inl(vg->io_gpo);

		if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))

			ret = 1;

	} else {

		reg_in = inl(vg->io_gpi);

		if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))

			ret = 1;

	}



	return ret;

}



static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,

			  int val)

{

	struct vx855_gpio *vg = container_of(gpio, struct vx855_gpio, gpio);

	unsigned long flags;

	u_int32_t reg_out;



	/* True GPI cannot be switched to output mode */

	if (nr < NR_VX855_GPI)

		return;



	spin_lock_irqsave(&vg->lock, flags);

	reg_out = inl(vg->io_gpo);

	if (nr < NR_VX855_GPInO) {

		if (val)

			reg_out |= gpo_o_bit(nr - NR_VX855_GPI);

		else

			reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);

	} else {

		if (val)

			reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);

		else

			reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);

	}

	outl(reg_out, vg->io_gpo);

	spin_unlock_irqrestore(&vg->lock, flags);

}



static int vx855gpio_direction_output(struct gpio_chip *gpio,

				      unsigned int nr, int val)

{

	/* True GPI cannot be switched to output mode */

	if (nr < NR_VX855_GPI)

		return -EINVAL;



	/* True GPO don't need to be switched to output mode,

	 * and GPIO are open-drain, i.e. also need no switching,

	 * so all we do is set the level */

	vx855gpio_set(gpio, nr, val);



	return 0;

}



static const char *vx855gpio_names[NR_VX855_GP] = {

	"VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",

	"VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",

	"VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",

	"VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",

	"VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",

	"VX855_GPO10", "VX855_GPO11", "VX855_GPO12",

	"VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",

	"VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",

	"VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",

	"VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"

};



static void vx855gpio_gpio_setup(struct vx855_gpio *vg)

{

	struct gpio_chip *c = &vg->gpio;



	c->label = "VX855 South Bridge";

	c->owner = THIS_MODULE;

	c->direction_input = vx855gpio_direction_input;

	c->direction_output = vx855gpio_direction_output;

	c->get = vx855gpio_get;

	c->set = vx855gpio_set;

	c->dbg_show = NULL;

	c->base = 0;

	c->ngpio = NR_VX855_GP;

	c->can_sleep = 0;

	c->names = vx855gpio_names;

}



/* This platform device is ordinarily registered by the vx855 mfd driver */

static __devinit int vx855gpio_probe(struct platform_device *pdev)

{

	struct resource *res_gpi;

	struct resource *res_gpo;

	struct vx855_gpio *vg;

	int ret;



	res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);

	res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);

	if (!res_gpi || !res_gpo)

		return -EBUSY;



	vg = kzalloc(sizeof(*vg), GFP_KERNEL);

	if (!vg)

		return -ENOMEM;



	platform_set_drvdata(pdev, vg);



	dev_info(&pdev->dev, "found VX855 GPIO controller\n");

	vg->io_gpi = res_gpi->start;

	vg->io_gpo = res_gpo->start;

	spin_lock_init(&vg->lock);



	/*

	 * A single byte is used to control various GPIO ports on the VX855,

	 * and in the case of the OLPC XO-1.5, some of those ports are used

	 * for switches that are interpreted and exposed through ACPI. ACPI

	 * will have reserved the region, so our own reservation will not

	 * succeed. Ignore and continue.

	 */



	if (!request_region(res_gpi->start, resource_size(res_gpi),

			MODULE_NAME "_gpi"))

		dev_warn(&pdev->dev,

			"GPI I/O resource busy, probably claimed by ACPI\n");

	else

		vg->gpi_reserved = true;



	if (!request_region(res_gpo->start, resource_size(res_gpo),

			MODULE_NAME "_gpo"))

		dev_warn(&pdev->dev,

			"GPO I/O resource busy, probably claimed by ACPI\n");

	else

		vg->gpo_reserved = true;



	vx855gpio_gpio_setup(vg);



	ret = gpiochip_add(&vg->gpio);

	if (ret) {

		dev_err(&pdev->dev, "failed to register GPIOs\n");

		goto out_release;

	}



	return 0;



out_release:

	if (vg->gpi_reserved)

		release_region(res_gpi->start, resource_size(res_gpi));

	if (vg->gpo_reserved)

		release_region(res_gpi->start, resource_size(res_gpo));

	platform_set_drvdata(pdev, NULL);

	kfree(vg);

	return ret;

}



static int __devexit vx855gpio_remove(struct platform_device *pdev)

{

	struct vx855_gpio *vg = platform_get_drvdata(pdev);

	struct resource *res;



	if (gpiochip_remove(&vg->gpio))

		dev_err(&pdev->dev, "unable to remove gpio_chip?\n");



	if (vg->gpi_reserved) {

		res = platform_get_resource(pdev, IORESOURCE_IO, 0);

		release_region(res->start, resource_size(res));

	}

	if (vg->gpo_reserved) {

		res = platform_get_resource(pdev, IORESOURCE_IO, 1);

		release_region(res->start, resource_size(res));

	}



	platform_set_drvdata(pdev, NULL);

	kfree(vg);

	return 0;

}



static struct platform_driver vx855gpio_driver = {

	.driver = {

		.name	= MODULE_NAME,

		.owner	= THIS_MODULE,

	},

	.probe		= vx855gpio_probe,

	.remove		= __devexit_p(vx855gpio_remove),

};



static int vx855gpio_init(void)

{

	return platform_driver_register(&vx855gpio_driver);

}

module_init(vx855gpio_init);



static void vx855gpio_exit(void)

{

	platform_driver_unregister(&vx855gpio_driver);

}

module_exit(vx855gpio_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");

MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");

MODULE_ALIAS("platform:vx855_gpio");