Commit 7e0de022 authored by Jonathan Corbet's avatar Jonathan Corbet
Browse files

viafb: add a driver for GPIO lines 



This is a simple gpiolib driver giving access to the GPIO lines in the
VIA framebuffer system.  A simple mechanism exists for switching lines
between GPIO and I2C, but it's only compile-time for now.

Cc: ScottFang@viatech.com.cn
Cc: JosephChan@via.com.tw
Cc: Harald Welte <laforge@gnumonks.org>
Acked-by: default avatarFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 24b4d82e

drivers/video/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -1511,6 +1511,7 @@ config FB_VIA 
       select FB_CFB_IMAGEBLIT

       select I2C_ALGOBIT

       select I2C

       select GPIOLIB

       help

	  This is the frame buffer device driver for Graphics chips of VIA

	  UniChrome (Pro) Family (CLE266,PM800/CN400,P4M800CE/P4M800Pro/
@@ -1520,6 +1521,7 @@ config FB_VIA 


	  To compile this driver as a module, choose M here: the

	  module will be called viafb.



config FB_NEOMAGIC

	tristate "NeoMagic display support"

	depends on FB && PCI

drivers/video/via/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -4,4 +4,7 @@ 


obj-$(CONFIG_FB_VIA) += viafb.o



viafb-y	:=viafbdev.o hw.o via_i2c.o dvi.o lcd.o ioctl.o accel.o via_utility.o vt1636.o global.o tblDPASetting.o viamode.o tbl1636.o via-core.o
 
viafb-y	:=viafbdev.o hw.o via_i2c.o dvi.o lcd.o ioctl.o accel.o \

	via_utility.o vt1636.o global.o tblDPASetting.o viamode.o tbl1636.o \

	via-core.o via-gpio.o

drivers/video/via/via-core.c

+7 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
 */

#include "via-core.h"

#include "via_i2c.h"

#include "via-gpio.h"

#include "global.h"



#include <linux/module.h>
@@ -221,6 +222,11 @@ static int __devinit via_pci_probe(struct pci_dev *pdev, 
	ret = via_fb_pci_probe(&global_dev);

	if (ret)

		goto out_i2c;

	/*

	 * Create the GPIOs.  We continue whether or not this succeeds;

	 * the framebuffer might be useful even without GPIO ports.

	 */

	ret = viafb_create_gpios(&global_dev, adap_configs);

	return 0;



out_i2c:
@@ -234,6 +240,7 @@ out_disable: 


static void __devexit via_pci_remove(struct pci_dev *pdev)

{

	viafb_destroy_gpios();

	viafb_delete_i2c_busses();

	via_fb_pci_remove(pdev);

	via_pci_teardown_mmio(&global_dev);

drivers/video/via/via-gpio.c

0 → 100644
+268 −0
Original line number Diff line number Diff line 
/*

 * Support for viafb GPIO ports.

 *

 * Copyright 2009 Jonathan Corbet <corbet@lwn.net>

 * Distributable under version 2 of the GNU General Public License.

 */



#include <linux/spinlock.h>

#include <linux/gpio.h>

#include "via-core.h"

#include "via-gpio.h"

#include "global.h"



/*

 * The ports we know about.  Note that the port-25 gpios are not

 * mentioned in the datasheet.

 */



struct viafb_gpio {

	char *vg_name;	/* Data sheet name */

	u16 vg_io_port;

	u8  vg_port_index;

	int  vg_mask_shift;

};



static struct viafb_gpio viafb_all_gpios[] = {

	{

		.vg_name = "VGPIO0",  /* Guess - not in datasheet */

		.vg_io_port = VIASR,

		.vg_port_index = 0x25,

		.vg_mask_shift = 1

	},

	{

		.vg_name = "VGPIO1",

		.vg_io_port = VIASR,

		.vg_port_index = 0x25,

		.vg_mask_shift = 0

	},

	{

		.vg_name = "VGPIO2",  /* aka DISPCLKI0 */

		.vg_io_port = VIASR,

		.vg_port_index = 0x2c,

		.vg_mask_shift = 1

	},

	{

		.vg_name = "VGPIO3",  /* aka DISPCLKO0 */

		.vg_io_port = VIASR,

		.vg_port_index = 0x2c,

		.vg_mask_shift = 0

	},

	{

		.vg_name = "VGPIO4",  /* DISPCLKI1 */

		.vg_io_port = VIASR,

		.vg_port_index = 0x3d,

		.vg_mask_shift = 1

	},

	{

		.vg_name = "VGPIO5",  /* DISPCLKO1 */

		.vg_io_port = VIASR,

		.vg_port_index = 0x3d,

		.vg_mask_shift = 0

	},

};



#define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)



/*

 * This structure controls the active GPIOs, which may be a subset

 * of those which are known.

 */



struct viafb_gpio_cfg {

	struct gpio_chip gpio_chip;

	struct viafb_dev *vdev;

	struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];

	char *gpio_names[VIAFB_NUM_GPIOS];

};



/*

 * GPIO access functions

 */

static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,

			 int value)

{

	struct viafb_gpio_cfg *cfg = container_of(chip,

						  struct viafb_gpio_cfg,

						  gpio_chip);

	u8 reg;

	struct viafb_gpio *gpio;

	unsigned long flags;



	spin_lock_irqsave(&cfg->vdev->reg_lock, flags);

	gpio = cfg->active_gpios[nr];

	reg = viafb_read_reg(VIASR, gpio->vg_port_index);

	reg |= 0x40 << gpio->vg_mask_shift;  /* output enable */

	if (value)

		reg |= 0x10 << gpio->vg_mask_shift;

	else

		reg &= ~(0x10 << gpio->vg_mask_shift);

	viafb_write_reg(gpio->vg_port_index, VIASR, reg);

	spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);

}



static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,

			    int value)

{

	via_gpio_set(chip, nr, value);

	return 0;

}



/*

 * Set the input direction.  I'm not sure this is right; we should

 * be able to do input without disabling output.

 */

static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)

{

	struct viafb_gpio_cfg *cfg = container_of(chip,

						  struct viafb_gpio_cfg,

						  gpio_chip);

	struct viafb_gpio *gpio;

	unsigned long flags;



	spin_lock_irqsave(&cfg->vdev->reg_lock, flags);

	gpio = cfg->active_gpios[nr];

	viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0,

			     0x40 << gpio->vg_mask_shift);

	spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);

	return 0;

}



static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)

{

	struct viafb_gpio_cfg *cfg = container_of(chip,

						  struct viafb_gpio_cfg,

						  gpio_chip);

	u8 reg;

	struct viafb_gpio *gpio;

	unsigned long flags;



	spin_lock_irqsave(&cfg->vdev->reg_lock, flags);

	gpio = cfg->active_gpios[nr];

	reg = viafb_read_reg(VIASR, gpio->vg_port_index);

	spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);

	return reg & (0x04 << gpio->vg_mask_shift);

}





static struct viafb_gpio_cfg gpio_config = {

	.gpio_chip = {

		.label = "VIAFB onboard GPIO",

		.owner = THIS_MODULE,

		.direction_output = via_gpio_dir_out,

		.set = via_gpio_set,

		.direction_input = via_gpio_dir_input,

		.get = via_gpio_get,

		.base = -1,

		.ngpio = 0,

		.can_sleep = 0

	}

};



/*

 * Manage the software enable bit.

 */

static void viafb_gpio_enable(struct viafb_gpio *gpio)

{

	viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0x02, 0x02);

}



static void viafb_gpio_disable(struct viafb_gpio *gpio)

{

	viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0, 0x02);

}









int viafb_create_gpios(struct viafb_dev *vdev,

		const struct via_port_cfg *port_cfg)

{

	int i, ngpio = 0, ret;

	struct viafb_gpio *gpio;

	unsigned long flags;



	/*

	 * Set up entries for all GPIOs which have been configured to

	 * operate as such (as opposed to as i2c ports).

	 */

	for (i = 0; i < VIAFB_NUM_PORTS; i++) {

		if (port_cfg[i].mode != VIA_MODE_GPIO)

			continue;

		for (gpio = viafb_all_gpios;

		     gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)

			if (gpio->vg_port_index == port_cfg[i].ioport_index) {

				gpio_config.active_gpios[ngpio] = gpio;

				gpio_config.gpio_names[ngpio] = gpio->vg_name;

				ngpio++;

			}

	}

	gpio_config.gpio_chip.ngpio = ngpio;

	gpio_config.gpio_chip.names = gpio_config.gpio_names;

	gpio_config.vdev = vdev;

	if (ngpio == 0) {

		printk(KERN_INFO "viafb: no GPIOs configured\n");

		return 0;

	}

	/*

	 * Enable the ports.  They come in pairs, with a single

	 * enable bit for both.

	 */

	spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);

	for (i = 0; i < ngpio; i += 2)

		viafb_gpio_enable(gpio_config.active_gpios[i]);

	spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);

	/*

	 * Get registered.

	 */

	gpio_config.gpio_chip.base = -1;  /* Dynamic */

	ret = gpiochip_add(&gpio_config.gpio_chip);

	if (ret) {

		printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);

		gpio_config.gpio_chip.ngpio = 0;

	}

	return ret;

/* Port enable ? */

}





int viafb_destroy_gpios(void)

{

	unsigned long flags;

	int ret = 0, i;



	spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);

	/*

	 * Get unregistered.

	 */

	if (gpio_config.gpio_chip.ngpio > 0) {

		ret = gpiochip_remove(&gpio_config.gpio_chip);

		if (ret) { /* Somebody still using it? */

			printk(KERN_ERR "Viafb: GPIO remove failed\n");

			goto out;

		}

	}

	/*

	 * Disable the ports.

	 */

	for (i = 0; i < gpio_config.gpio_chip.ngpio; i += 2)

		viafb_gpio_disable(gpio_config.active_gpios[i]);

	gpio_config.gpio_chip.ngpio = 0;

out:

	spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);

	return ret;

}



/*

 * Look up a specific gpio and return the number it was assigned.

 */

int viafb_gpio_lookup(const char *name)

{

	int i;



	for (i = 0; i < gpio_config.gpio_chip.ngpio; i++)

		if (!strcmp(name, gpio_config.active_gpios[i]->vg_name))

			return gpio_config.gpio_chip.base + i;

	return -1;

}

EXPORT_SYMBOL_GPL(viafb_gpio_lookup);

drivers/video/via/via-gpio.h

0 → 100644
+15 −0
Original line number Diff line number Diff line 
/*

 * Support for viafb GPIO ports.

 *

 * Copyright 2009 Jonathan Corbet <corbet@lwn.net>

 * Distributable under version 2 of the GNU General Public License.

 */



#ifndef __VIA_GPIO_H__

#define __VIA_GPIO_H__



extern int viafb_create_gpios(struct viafb_dev *vdev,

		const struct via_port_cfg *port_cfg);

extern int viafb_destroy_gpios(void);

extern int viafb_gpio_lookup(const char *name);

#endif

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