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GPIO: add new Xilinx driver for powerpc
This driver supports the Xilinx XPS GPIO IP core which has the typical GPIO features. Signed-off-by: Kiran Sutariya <[email protected]> Signed-off-by: John Linn <[email protected]> Cc: David Brownell <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Kumar Gala <[email protected]> Cc: "Grant Likely" <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,235 @@ | ||
| /* | ||
| * 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> | ||
|
|
||
| /* 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; | ||
| struct of_gpio_chip *ofchip; | ||
| int status = 0; | ||
| const u32 *tree_info; | ||
|
|
||
| chip = kzalloc(sizeof(*chip), GFP_KERNEL); | ||
| if (!chip) | ||
| return -ENOMEM; | ||
| ofchip = &chip->mmchip.of_gc; | ||
|
|
||
| /* Update GPIO state shadow register with default value */ | ||
| tree_info = of_get_property(np, "xlnx,dout-default", NULL); | ||
| if (tree_info) | ||
| chip->gpio_state = *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 = *tree_info; | ||
|
|
||
| /* Check device node and parent device node for device width */ | ||
| ofchip->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) | ||
| ofchip->gc.ngpio = *tree_info; | ||
|
|
||
| spin_lock_init(&chip->gpio_lock); | ||
|
|
||
| ofchip->gpio_cells = 2; | ||
| ofchip->gc.direction_input = xgpio_dir_in; | ||
| ofchip->gc.direction_output = xgpio_dir_out; | ||
| ofchip->gc.get = xgpio_get; | ||
| ofchip->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"); |