[PATCH] [powerpc] GPIO: Adding new Xilinx driver
Grant Likely
grant.likely at secretlab.ca
Sat Oct 25 07:03:39 EST 2008
On Fri, Oct 24, 2008 at 1:59 PM, John Linn <john.linn at xilinx.com> wrote:
> This driver supports the Xilinx XPS GPIO IP core which has the typical
> GPIO features.
>
> Signed-off-by: Kiran Sutariya <kirans at xilinx.com>
> Signed-off-by: John Linn <john.linn at xilinx.com>
Acked-by: Grant Likely <grant.likely at secretlab.ca>
> ---
> drivers/gpio/Kconfig | 8 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/xilinx_gpio.c | 240 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 249 insertions(+), 0 deletions(-)
> create mode 100644 drivers/gpio/xilinx_gpio.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 7f2ee27..f6b0da8 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -65,6 +65,14 @@ config GPIO_SYSFS
>
> # put expanders in the right section, in alphabetical order
>
> +comment "Memory mapped GPIO expanders:"
> +
> +config GPIO_XILINX
> + bool "Xilinx GPIO support"
> + depends on OF
> + help
> + Say yes here to support the Xilinx FPGA GPIO device
> +
> comment "I2C GPIO expanders:"
>
> config GPIO_MAX732X
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 6aafdeb..49ac64e 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -10,4 +10,5 @@ obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
> obj-$(CONFIG_GPIO_PCA953X) += pca953x.o
> obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o
> obj-$(CONFIG_GPIO_TWL4030) += twl4030-gpio.o
> +obj-$(CONFIG_GPIO_XILINX) += xilinx_gpio.o
> obj-$(CONFIG_GPIO_BT8XX) += bt8xxgpio.o
> diff --git a/drivers/gpio/xilinx_gpio.c b/drivers/gpio/xilinx_gpio.c
> new file mode 100644
> index 0000000..224d0d5
> --- /dev/null
> +++ b/drivers/gpio/xilinx_gpio.c
> @@ -0,0 +1,240 @@
> +/*
> + * 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/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_of_probe - Probe method for the GPIO device.
> + * @of_dev: pointer to OF device structure.
> + * @match: pointer to the structure used for matching a device.
> + *
> + * 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 of_device *ofdev,
> + const struct of_device_id *match)
> +{
> + 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(ofdev->node, "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(ofdev->node, "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(ofdev->node, "xlnx,gpio-width", NULL);
> + if (!tree_info)
> + tree_info = of_get_property(ofdev->node->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;
> +
> + /* Call the OF gpio helper to setup and register the GPIO device */
> + status = of_mm_gpiochip_add(ofdev->node, &chip->mmchip);
> + if (status) {
> + kfree(chip);
> + dev_err(&ofdev->dev, "Error in probe function error value %d\n",
> + status);
> + return status;
> + }
> +
> + /* Finally, write the initial state to the device */
> + out_be32(chip->mmchip.regs + XGPIO_DATA_OFFSET, chip->gpio_state);
> + out_be32(chip->mmchip.regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
> +
> + dev_info(&ofdev->dev, "registered Xilinx GPIO controller\n");
> + return 0;
> +}
> +
> +/**
> + * xgpio_of_remove - Remove method for the GPIO device.
> + * @of_dev: pointer to OF device structure.
> + *
> + * This function returns a negative error as we cannot unregister GPIO chips.
> + */
> +static int __devexit xgpio_of_remove(struct of_device *ofdev)
> +{
> + return -EBUSY;
> +}
> +
> +static struct of_device_id xgpio_of_match[] __devinitdata = {
> + { .compatible = "xlnx,xps-gpio-1.00.a", },
> + { /* end of list */ },
> +};
> +
> +MODULE_DEVICE_TABLE(of, xgpio_of_match);
> +
> +static struct of_platform_driver xgpio_of_driver = {
> + .name = "xilinx_gpio",
> + .match_table = xgpio_of_match,
> + .probe = xgpio_of_probe,
> + .remove = __devexit_p(xgpio_of_remove),
> +};
> +
> +static int __init xgpio_init(void)
> +{
> + return of_register_platform_driver(&xgpio_of_driver);
> +}
> +
> +/* 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");
> --
> 1.5.2.1
>
>
>
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--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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