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- /*
- * 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/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");
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