ASoC: ep93xx i2s audio driver
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / gpio / xilinx_gpio.c
blobb8fa65b5bfca56ca8320e23916d45dbc56a68b1c
1 /*
2 * Xilinx gpio driver
4 * Copyright 2008 Xilinx, Inc.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2
8 * as published by the Free Software Foundation.
10 * You should have received a copy of the GNU General Public License
11 * along with this program; if not, write to the Free Software
12 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
15 #include <linux/init.h>
16 #include <linux/errno.h>
17 #include <linux/of_device.h>
18 #include <linux/of_platform.h>
19 #include <linux/of_gpio.h>
20 #include <linux/io.h>
21 #include <linux/gpio.h>
22 #include <linux/slab.h>
24 /* Register Offset Definitions */
25 #define XGPIO_DATA_OFFSET (0x0) /* Data register */
26 #define XGPIO_TRI_OFFSET (0x4) /* I/O direction register */
28 struct xgpio_instance {
29 struct of_mm_gpio_chip mmchip;
30 u32 gpio_state; /* GPIO state shadow register */
31 u32 gpio_dir; /* GPIO direction shadow register */
32 spinlock_t gpio_lock; /* Lock used for synchronization */
35 /**
36 * xgpio_get - Read the specified signal of the GPIO device.
37 * @gc: Pointer to gpio_chip device structure.
38 * @gpio: GPIO signal number.
40 * This function reads the specified signal of the GPIO device. It returns 0 if
41 * the signal clear, 1 if signal is set or negative value on error.
43 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
45 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
47 return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
50 /**
51 * xgpio_set - Write the specified signal of the GPIO device.
52 * @gc: Pointer to gpio_chip device structure.
53 * @gpio: GPIO signal number.
54 * @val: Value to be written to specified signal.
56 * This function writes the specified value in to the specified signal of the
57 * GPIO device.
59 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
61 unsigned long flags;
62 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
63 struct xgpio_instance *chip =
64 container_of(mm_gc, struct xgpio_instance, mmchip);
66 spin_lock_irqsave(&chip->gpio_lock, flags);
68 /* Write to GPIO signal and set its direction to output */
69 if (val)
70 chip->gpio_state |= 1 << gpio;
71 else
72 chip->gpio_state &= ~(1 << gpio);
73 out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
75 spin_unlock_irqrestore(&chip->gpio_lock, flags);
78 /**
79 * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
80 * @gc: Pointer to gpio_chip device structure.
81 * @gpio: GPIO signal number.
83 * This function sets the direction of specified GPIO signal as input.
84 * It returns 0 if direction of GPIO signals is set as input otherwise it
85 * returns negative error value.
87 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
89 unsigned long flags;
90 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
91 struct xgpio_instance *chip =
92 container_of(mm_gc, struct xgpio_instance, mmchip);
94 spin_lock_irqsave(&chip->gpio_lock, flags);
96 /* Set the GPIO bit in shadow register and set direction as input */
97 chip->gpio_dir |= (1 << gpio);
98 out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
100 spin_unlock_irqrestore(&chip->gpio_lock, flags);
102 return 0;
106 * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
107 * @gc: Pointer to gpio_chip device structure.
108 * @gpio: GPIO signal number.
109 * @val: Value to be written to specified signal.
111 * This function sets the direction of specified GPIO signal as output. If all
112 * GPIO signals of GPIO chip is configured as input then it returns
113 * error otherwise it returns 0.
115 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
117 unsigned long flags;
118 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
119 struct xgpio_instance *chip =
120 container_of(mm_gc, struct xgpio_instance, mmchip);
122 spin_lock_irqsave(&chip->gpio_lock, flags);
124 /* Write state of GPIO signal */
125 if (val)
126 chip->gpio_state |= 1 << gpio;
127 else
128 chip->gpio_state &= ~(1 << gpio);
129 out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
131 /* Clear the GPIO bit in shadow register and set direction as output */
132 chip->gpio_dir &= (~(1 << gpio));
133 out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
135 spin_unlock_irqrestore(&chip->gpio_lock, flags);
137 return 0;
141 * xgpio_save_regs - Set initial values of GPIO pins
142 * @mm_gc: pointer to memory mapped GPIO chip structure
144 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
146 struct xgpio_instance *chip =
147 container_of(mm_gc, struct xgpio_instance, mmchip);
149 out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
150 out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
154 * xgpio_of_probe - Probe method for the GPIO device.
155 * @np: pointer to device tree node
157 * This function probes the GPIO device in the device tree. It initializes the
158 * driver data structure. It returns 0, if the driver is bound to the GPIO
159 * device, or a negative value if there is an error.
161 static int __devinit xgpio_of_probe(struct device_node *np)
163 struct xgpio_instance *chip;
164 struct of_gpio_chip *ofchip;
165 int status = 0;
166 const u32 *tree_info;
168 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
169 if (!chip)
170 return -ENOMEM;
171 ofchip = &chip->mmchip.of_gc;
173 /* Update GPIO state shadow register with default value */
174 tree_info = of_get_property(np, "xlnx,dout-default", NULL);
175 if (tree_info)
176 chip->gpio_state = *tree_info;
178 /* Update GPIO direction shadow register with default value */
179 chip->gpio_dir = 0xFFFFFFFF; /* By default, all pins are inputs */
180 tree_info = of_get_property(np, "xlnx,tri-default", NULL);
181 if (tree_info)
182 chip->gpio_dir = *tree_info;
184 /* Check device node and parent device node for device width */
185 ofchip->gc.ngpio = 32; /* By default assume full GPIO controller */
186 tree_info = of_get_property(np, "xlnx,gpio-width", NULL);
187 if (!tree_info)
188 tree_info = of_get_property(np->parent,
189 "xlnx,gpio-width", NULL);
190 if (tree_info)
191 ofchip->gc.ngpio = *tree_info;
193 spin_lock_init(&chip->gpio_lock);
195 ofchip->gpio_cells = 2;
196 ofchip->gc.direction_input = xgpio_dir_in;
197 ofchip->gc.direction_output = xgpio_dir_out;
198 ofchip->gc.get = xgpio_get;
199 ofchip->gc.set = xgpio_set;
201 chip->mmchip.save_regs = xgpio_save_regs;
203 /* Call the OF gpio helper to setup and register the GPIO device */
204 status = of_mm_gpiochip_add(np, &chip->mmchip);
205 if (status) {
206 kfree(chip);
207 pr_err("%s: error in probe function with status %d\n",
208 np->full_name, status);
209 return status;
211 pr_info("XGpio: %s: registered\n", np->full_name);
212 return 0;
215 static struct of_device_id xgpio_of_match[] __devinitdata = {
216 { .compatible = "xlnx,xps-gpio-1.00.a", },
217 { /* end of list */ },
220 static int __init xgpio_init(void)
222 struct device_node *np;
224 for_each_matching_node(np, xgpio_of_match)
225 xgpio_of_probe(np);
227 return 0;
230 /* Make sure we get initialized before anyone else tries to use us */
231 subsys_initcall(xgpio_init);
232 /* No exit call at the moment as we cannot unregister of GPIO chips */
234 MODULE_AUTHOR("Xilinx, Inc.");
235 MODULE_DESCRIPTION("Xilinx GPIO driver");
236 MODULE_LICENSE("GPL");