[PATCH] [V3][powerpc] GPIO: Adding new Xilinx driver
John Linn
john.linn at xilinx.com
Tue Oct 28 06:00:46 EST 2008
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: Grant Likely <grant.likely at secretlab.ca>
Signed-off-by: John Linn <john.linn at xilinx.com>
---
V2 - Updated based on Anton's comments
V3 - Cleaned up Kconfig badness in patch generation and added Grant's signoff
drivers/gpio/Kconfig | 8 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/xilinx_gpio.c | 235 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 244 insertions(+), 0 deletions(-)
create mode 100644 drivers/gpio/xilinx_gpio.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 7f2ee27..48f49d9 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 PPC_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..3c1177a
--- /dev/null
+++ b/drivers/gpio/xilinx_gpio.c
@@ -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");
--
1.5.2.1
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