diff options
Diffstat (limited to 'kernel/drivers/gpio/gpio-xilinx.c')
| -rw-r--r-- | kernel/drivers/gpio/gpio-xilinx.c | 356 |
1 files changed, 356 insertions, 0 deletions
diff --git a/kernel/drivers/gpio/gpio-xilinx.c b/kernel/drivers/gpio/gpio-xilinx.c new file mode 100644 index 000000000..61243d177 --- /dev/null +++ b/kernel/drivers/gpio/gpio-xilinx.c @@ -0,0 +1,356 @@ +/* + * Xilinx gpio driver for xps/axi_gpio IP. + * + * Copyright 2008 - 2013 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/bitops.h> +#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 */ + +#define XGPIO_CHANNEL_OFFSET 0x8 + +/* Read/Write access to the GPIO registers */ +#if defined(CONFIG_ARCH_ZYNQ) || defined(CONFIG_X86) +# define xgpio_readreg(offset) readl(offset) +# define xgpio_writereg(offset, val) writel(val, offset) +#else +# define xgpio_readreg(offset) __raw_readl(offset) +# define xgpio_writereg(offset, val) __raw_writel(val, offset) +#endif + +/** + * struct xgpio_instance - Stores information about GPIO device + * @mmchip: OF GPIO chip for memory mapped banks + * @gpio_state: GPIO state shadow register + * @gpio_dir: GPIO direction shadow register + * @gpio_lock: Lock used for synchronization + * @inited: True if the port has been inited + */ +struct xgpio_instance { + struct of_mm_gpio_chip mmchip; + unsigned int gpio_width[2]; + u32 gpio_state[2]; + u32 gpio_dir[2]; + spinlock_t gpio_lock[2]; +}; + +static inline int xgpio_index(struct xgpio_instance *chip, int gpio) +{ + if (gpio >= chip->gpio_width[0]) + return 1; + + return 0; +} + +static inline int xgpio_regoffset(struct xgpio_instance *chip, int gpio) +{ + if (xgpio_index(chip, gpio)) + return XGPIO_CHANNEL_OFFSET; + + return 0; +} + +static inline int xgpio_offset(struct xgpio_instance *chip, int gpio) +{ + if (xgpio_index(chip, gpio)) + return gpio - chip->gpio_width[0]; + + return gpio; +} + +/** + * 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. + * + * Return: + * 0 if direction of GPIO signals is set as input otherwise it + * returns negative error value. + */ +static int xgpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + 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); + u32 val; + + val = xgpio_readreg(mm_gc->regs + XGPIO_DATA_OFFSET + + xgpio_regoffset(chip, gpio)); + + return !!(val & BIT(xgpio_offset(chip, gpio))); +} + +/** + * 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); + int index = xgpio_index(chip, gpio); + int offset = xgpio_offset(chip, gpio); + + spin_lock_irqsave(&chip->gpio_lock[index], flags); + + /* Write to GPIO signal and set its direction to output */ + if (val) + chip->gpio_state[index] |= BIT(offset); + else + chip->gpio_state[index] &= ~BIT(offset); + + xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + + xgpio_regoffset(chip, gpio), chip->gpio_state[index]); + + spin_unlock_irqrestore(&chip->gpio_lock[index], 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. + * + * Return: + * 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); + int index = xgpio_index(chip, gpio); + int offset = xgpio_offset(chip, gpio); + + spin_lock_irqsave(&chip->gpio_lock[index], flags); + + /* Set the GPIO bit in shadow register and set direction as input */ + chip->gpio_dir[index] |= BIT(offset); + xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + + xgpio_regoffset(chip, gpio), chip->gpio_dir[index]); + + spin_unlock_irqrestore(&chip->gpio_lock[index], 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. + * + * Return: + * 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); + int index = xgpio_index(chip, gpio); + int offset = xgpio_offset(chip, gpio); + + spin_lock_irqsave(&chip->gpio_lock[index], flags); + + /* Write state of GPIO signal */ + if (val) + chip->gpio_state[index] |= BIT(offset); + else + chip->gpio_state[index] &= ~BIT(offset); + xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + + xgpio_regoffset(chip, gpio), chip->gpio_state[index]); + + /* Clear the GPIO bit in shadow register and set direction as output */ + chip->gpio_dir[index] &= ~BIT(offset); + xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + + xgpio_regoffset(chip, gpio), chip->gpio_dir[index]); + + spin_unlock_irqrestore(&chip->gpio_lock[index], 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); + + xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state[0]); + xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]); + + if (!chip->gpio_width[1]) + return; + + xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_TRI_OFFSET, + chip->gpio_state[1]); + xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_TRI_OFFSET, + chip->gpio_dir[1]); +} + +/** + * xgpio_remove - Remove method for the GPIO device. + * @pdev: pointer to the platform device + * + * This function remove gpiochips and frees all the allocated resources. + */ +static int xgpio_remove(struct platform_device *pdev) +{ + struct xgpio_instance *chip = platform_get_drvdata(pdev); + + of_mm_gpiochip_remove(&chip->mmchip); + + return 0; +} + +/** + * xgpio_of_probe - Probe method for the GPIO device. + * @pdev: pointer to the platform device + * + * Return: + * It returns 0, if the driver is bound to the GPIO device, or + * a negative value if there is an error. + */ +static int xgpio_probe(struct platform_device *pdev) +{ + struct xgpio_instance *chip; + int status = 0; + struct device_node *np = pdev->dev.of_node; + u32 is_dual; + + chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + platform_set_drvdata(pdev, chip); + + /* Update GPIO state shadow register with default value */ + of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]); + + /* Update GPIO direction shadow register with default value */ + if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0])) + chip->gpio_dir[0] = 0xFFFFFFFF; + + /* + * Check device node and parent device node for device width + * and assume default width of 32 + */ + if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0])) + chip->gpio_width[0] = 32; + + spin_lock_init(&chip->gpio_lock[0]); + + if (of_property_read_u32(np, "xlnx,is-dual", &is_dual)) + is_dual = 0; + + if (is_dual) { + /* Update GPIO state shadow register with default value */ + of_property_read_u32(np, "xlnx,dout-default-2", + &chip->gpio_state[1]); + + /* Update GPIO direction shadow register with default value */ + if (of_property_read_u32(np, "xlnx,tri-default-2", + &chip->gpio_dir[1])) + chip->gpio_dir[1] = 0xFFFFFFFF; + + /* + * Check device node and parent device node for device width + * and assume default width of 32 + */ + if (of_property_read_u32(np, "xlnx,gpio2-width", + &chip->gpio_width[1])) + chip->gpio_width[1] = 32; + + spin_lock_init(&chip->gpio_lock[1]); + } + + chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1]; + chip->mmchip.gc.dev = &pdev->dev; + 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) { + pr_err("%s: error in probe function with status %d\n", + np->full_name, status); + return status; + } + + return 0; +} + +static const struct of_device_id xgpio_of_match[] = { + { .compatible = "xlnx,xps-gpio-1.00.a", }, + { /* end of list */ }, +}; + +MODULE_DEVICE_TABLE(of, xgpio_of_match); + +static struct platform_driver xgpio_plat_driver = { + .probe = xgpio_probe, + .remove = xgpio_remove, + .driver = { + .name = "gpio-xilinx", + .of_match_table = xgpio_of_match, + }, +}; + +static int __init xgpio_init(void) +{ + return platform_driver_register(&xgpio_plat_driver); +} + +subsys_initcall(xgpio_init); + +static void __exit xgpio_exit(void) +{ + platform_driver_unregister(&xgpio_plat_driver); +} +module_exit(xgpio_exit); + +MODULE_AUTHOR("Xilinx, Inc."); +MODULE_DESCRIPTION("Xilinx GPIO driver"); +MODULE_LICENSE("GPL"); |