drivers/gpio/gpio-xilinx.c - kernel/common - Git at Google

 /*
  * Xilinx gpio driver
  *
  * Copyright 2008 Xilinx, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2
  * as published by the Free Software Foundation.
  *
  * 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/errno.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/of_gpio.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/slab.h>

 /* Register Offset Definitions */
 #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */
 #define XGPIO_TRI_OFFSET    (0x4)	/* I/O direction register  */

 struct xgpio_instance {
 	struct of_mm_gpio_chip mmchip;
 	u32 gpio_state;		/* GPIO state shadow register */
 	u32 gpio_dir;		/* GPIO direction shadow register */
 	spinlock_t gpio_lock;	/* Lock used for synchronization */
 };

 /**
  * xgpio_get - Read the specified signal of the GPIO device.
  * @gc:     Pointer to gpio_chip device structure.
  * @gpio:   GPIO signal number.
  *
  * This function reads the specified signal of the GPIO device. It returns 0 if
  * the signal clear, 1 if signal is set or negative value on error.
  */
 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
 {
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);

 	return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
 }

 /**
  * xgpio_set - Write the specified signal of the GPIO device.
  * @gc:     Pointer to gpio_chip device structure.
  * @gpio:   GPIO signal number.
  * @val:    Value to be written to specified signal.
  *
  * This function writes the specified value in to the specified signal of the
  * GPIO device.
  */
 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	unsigned long flags;
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);

 	spin_lock_irqsave(&chip->gpio_lock, flags);

 	/* Write to GPIO signal and set its direction to output */
 	if (val)
 		chip->gpio_state |= 1 << gpio;
 	else
 		chip->gpio_state &= ~(1 << gpio);
 	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);
 }

 /**
  * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
  * @gc:     Pointer to gpio_chip device structure.
  * @gpio:   GPIO signal number.
  *
  * This function sets the direction of specified GPIO signal as input.
  * It returns 0 if direction of GPIO signals is set as input otherwise it
  * returns negative error value.
  */
 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 {
 	unsigned long flags;
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);

 	spin_lock_irqsave(&chip->gpio_lock, flags);

 	/* Set the GPIO bit in shadow register and set direction as input */
 	chip->gpio_dir |= (1 << gpio);
 	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);

 	return 0;
 }

 /**
  * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
  * @gc:     Pointer to gpio_chip device structure.
  * @gpio:   GPIO signal number.
  * @val:    Value to be written to specified signal.
  *
  * This function sets the direction of specified GPIO signal as output. If all
  * GPIO signals of GPIO chip is configured as input then it returns
  * error otherwise it returns 0.
  */
 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	unsigned long flags;
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);

 	spin_lock_irqsave(&chip->gpio_lock, flags);

 	/* Write state of GPIO signal */
 	if (val)
 		chip->gpio_state |= 1 << gpio;
 	else
 		chip->gpio_state &= ~(1 << gpio);
 	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);

 	/* Clear the GPIO bit in shadow register and set direction as output */
 	chip->gpio_dir &= (~(1 << gpio));
 	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);

 	spin_unlock_irqrestore(&chip->gpio_lock, flags);

 	return 0;
 }

 /**
  * xgpio_save_regs - Set initial values of GPIO pins
  * @mm_gc: pointer to memory mapped GPIO chip structure
  */
 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 {
 	struct xgpio_instance *chip =
 	    container_of(mm_gc, struct xgpio_instance, mmchip);

 	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
 	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
 }

 /**
  * xgpio_of_probe - Probe method for the GPIO device.
  * @np: pointer to device tree node
  *
  * This function probes the GPIO device in the device tree. It initializes the
  * driver data structure. It returns 0, if the driver is bound to the GPIO
  * device, or a negative value if there is an error.
  */
 static int __devinit xgpio_of_probe(struct device_node *np)
 {
 	struct xgpio_instance *chip;
 	int status = 0;
 	const u32 *tree_info;

 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;

 	/* Update GPIO state shadow register with default value */
 	tree_info = of_get_property(np, "xlnx,dout-default", NULL);
 	if (tree_info)
 		chip->gpio_state = be32_to_cpup(tree_info);

 	/* Update GPIO direction shadow register with default value */
 	chip->gpio_dir = 0xFFFFFFFF; /* By default, all pins are inputs */
 	tree_info = of_get_property(np, "xlnx,tri-default", NULL);
 	if (tree_info)
 		chip->gpio_dir = be32_to_cpup(tree_info);

 	/* Check device node and parent device node for device width */
 	chip->mmchip.gc.ngpio = 32; /* By default assume full GPIO controller */
 	tree_info = of_get_property(np, "xlnx,gpio-width", NULL);
 	if (!tree_info)
 		tree_info = of_get_property(np->parent,
 					    "xlnx,gpio-width", NULL);
 	if (tree_info)
 		chip->mmchip.gc.ngpio = be32_to_cpup(tree_info);

 	spin_lock_init(&chip->gpio_lock);

 	chip->mmchip.gc.direction_input = xgpio_dir_in;
 	chip->mmchip.gc.direction_output = xgpio_dir_out;
 	chip->mmchip.gc.get = xgpio_get;
 	chip->mmchip.gc.set = xgpio_set;

 	chip->mmchip.save_regs = xgpio_save_regs;

 	/* Call the OF gpio helper to setup and register the GPIO device */
 	status = of_mm_gpiochip_add(np, &chip->mmchip);
 	if (status) {
 		kfree(chip);
 		pr_err("%s: error in probe function with status %d\n",
 		       np->full_name, status);
 		return status;
 	}
 	pr_info("XGpio: %s: registered\n", np->full_name);
 	return 0;
 }

 static struct of_device_id xgpio_of_match[] __devinitdata = {
 	{ .compatible = "xlnx,xps-gpio-1.00.a", },
 	{ /* end of list */ },
 };

 static int __init xgpio_init(void)
 {
 	struct device_node *np;

 	for_each_matching_node(np, xgpio_of_match)
 		xgpio_of_probe(np);

 	return 0;
 }

 /* Make sure we get initialized before anyone else tries to use us */
 subsys_initcall(xgpio_init);
 /* No exit call at the moment as we cannot unregister of GPIO chips */

 MODULE_AUTHOR("Xilinx, Inc.");
 MODULE_DESCRIPTION("Xilinx GPIO driver");
 MODULE_LICENSE("GPL");
	/*
	* Xilinx gpio driver
	*
	* Copyright 2008 Xilinx, Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2
	* as published by the Free Software Foundation.
	*
	* 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/errno.h>
	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/of_platform.h>
	#include <linux/of_gpio.h>
	#include <linux/io.h>
	#include <linux/gpio.h>
	#include <linux/slab.h>

	/* Register Offset Definitions */
	#define XGPIO_DATA_OFFSET (0x0) /* Data register */
	#define XGPIO_TRI_OFFSET (0x4) /* I/O direction register */

	struct xgpio_instance {
	struct of_mm_gpio_chip mmchip;
	u32 gpio_state; /* GPIO state shadow register */
	u32 gpio_dir; /* GPIO direction shadow register */
	spinlock_t gpio_lock; /* Lock used for synchronization */
	};

	/**
	* xgpio_get - Read the specified signal of the GPIO device.
	* @gc: Pointer to gpio_chip device structure.
	* @gpio: GPIO signal number.
	*
	* This function reads the specified signal of the GPIO device. It returns 0 if
	* the signal clear, 1 if signal is set or negative value on error.
	*/
	static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
	{
	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);

	return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
	}

	/**
	* xgpio_set - Write the specified signal of the GPIO device.
	* @gc: Pointer to gpio_chip device structure.
	* @gpio: GPIO signal number.
	* @val: Value to be written to specified signal.
	*
	* This function writes the specified value in to the specified signal of the
	* GPIO device.
	*/
	static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
	{
	unsigned long flags;
	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
	struct xgpio_instance *chip =
	container_of(mm_gc, struct xgpio_instance, mmchip);

	spin_lock_irqsave(&chip->gpio_lock, flags);

	/* Write to GPIO signal and set its direction to output */
	if (val)
	chip->gpio_state \|= 1 << gpio;
	else
	chip->gpio_state &= ~(1 << gpio);
	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);

	spin_unlock_irqrestore(&chip->gpio_lock, flags);
	}

	/**
	* xgpio_dir_in - Set the direction of the specified GPIO signal as input.
	* @gc: Pointer to gpio_chip device structure.
	* @gpio: GPIO signal number.
	*
	* This function sets the direction of specified GPIO signal as input.
	* It returns 0 if direction of GPIO signals is set as input otherwise it
	* returns negative error value.
	*/
	static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
	{
	unsigned long flags;
	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
	struct xgpio_instance *chip =
	container_of(mm_gc, struct xgpio_instance, mmchip);

	spin_lock_irqsave(&chip->gpio_lock, flags);

	/* Set the GPIO bit in shadow register and set direction as input */
	chip->gpio_dir \|= (1 << gpio);
	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);

	spin_unlock_irqrestore(&chip->gpio_lock, flags);

	return 0;
	}

	/**
	* xgpio_dir_out - Set the direction of the specified GPIO signal as output.
	* @gc: Pointer to gpio_chip device structure.
	* @gpio: GPIO signal number.
	* @val: Value to be written to specified signal.
	*
	* This function sets the direction of specified GPIO signal as output. If all
	* GPIO signals of GPIO chip is configured as input then it returns
	* error otherwise it returns 0.
	*/
	static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
	{
	unsigned long flags;
	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
	struct xgpio_instance *chip =
	container_of(mm_gc, struct xgpio_instance, mmchip);

	spin_lock_irqsave(&chip->gpio_lock, flags);

	/* Write state of GPIO signal */
	if (val)
	chip->gpio_state \|= 1 << gpio;
	else
	chip->gpio_state &= ~(1 << gpio);
	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);

	/* Clear the GPIO bit in shadow register and set direction as output */
	chip->gpio_dir &= (~(1 << gpio));
	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);

	spin_unlock_irqrestore(&chip->gpio_lock, flags);

	return 0;
	}

	/**
	* xgpio_save_regs - Set initial values of GPIO pins
	* @mm_gc: pointer to memory mapped GPIO chip structure
	*/
	static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
	{
	struct xgpio_instance *chip =
	container_of(mm_gc, struct xgpio_instance, mmchip);

	out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
	out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
	}

	/**
	* xgpio_of_probe - Probe method for the GPIO device.
	* @np: pointer to device tree node
	*
	* This function probes the GPIO device in the device tree. It initializes the
	* driver data structure. It returns 0, if the driver is bound to the GPIO
	* device, or a negative value if there is an error.
	*/
	static int __devinit xgpio_of_probe(struct device_node *np)
	{
	struct xgpio_instance *chip;
	int status = 0;
	const u32 *tree_info;

	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
	if (!chip)
	return -ENOMEM;

	/* Update GPIO state shadow register with default value */
	tree_info = of_get_property(np, "xlnx,dout-default", NULL);
	if (tree_info)
	chip->gpio_state = be32_to_cpup(tree_info);

	/* Update GPIO direction shadow register with default value */
	chip->gpio_dir = 0xFFFFFFFF; /* By default, all pins are inputs */
	tree_info = of_get_property(np, "xlnx,tri-default", NULL);
	if (tree_info)
	chip->gpio_dir = be32_to_cpup(tree_info);

	/* Check device node and parent device node for device width */
	chip->mmchip.gc.ngpio = 32; /* By default assume full GPIO controller */
	tree_info = of_get_property(np, "xlnx,gpio-width", NULL);
	if (!tree_info)
	tree_info = of_get_property(np->parent,
	"xlnx,gpio-width", NULL);
	if (tree_info)
	chip->mmchip.gc.ngpio = be32_to_cpup(tree_info);

	spin_lock_init(&chip->gpio_lock);

	chip->mmchip.gc.direction_input = xgpio_dir_in;
	chip->mmchip.gc.direction_output = xgpio_dir_out;
	chip->mmchip.gc.get = xgpio_get;
	chip->mmchip.gc.set = xgpio_set;

	chip->mmchip.save_regs = xgpio_save_regs;

	/* Call the OF gpio helper to setup and register the GPIO device */
	status = of_mm_gpiochip_add(np, &chip->mmchip);
	if (status) {
	kfree(chip);
	pr_err("%s: error in probe function with status %d\n",
	np->full_name, status);
	return status;
	}
	pr_info("XGpio: %s: registered\n", np->full_name);
	return 0;
	}

	static struct of_device_id xgpio_of_match[] __devinitdata = {
	{ .compatible = "xlnx,xps-gpio-1.00.a", },
	{ /* end of list */ },
	};

	static int __init xgpio_init(void)
	{
	struct device_node *np;

	for_each_matching_node(np, xgpio_of_match)
	xgpio_of_probe(np);

	return 0;
	}

	/* Make sure we get initialized before anyone else tries to use us */
	subsys_initcall(xgpio_init);
	/* No exit call at the moment as we cannot unregister of GPIO chips */

	MODULE_AUTHOR("Xilinx, Inc.");
	MODULE_DESCRIPTION("Xilinx GPIO driver");
	MODULE_LICENSE("GPL");