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-rw-r--r--drivers/gpio/gpio-xilinx.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
new file mode 100644
index 000000000000..846fbd5e31bf
--- /dev/null
+++ b/drivers/gpio/gpio-xilinx.c
@@ -0,0 +1,233 @@
1/*
2 * Xilinx gpio driver
3 *
4 * Copyright 2008 Xilinx, Inc.
5 *
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.
9 *
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
13 */
14
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>
23
24/* Register Offset Definitions */
25#define XGPIO_DATA_OFFSET (0x0) /* Data register */
26#define XGPIO_TRI_OFFSET (0x4) /* I/O direction register */
27
28struct 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 */
33};
34
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.
39 *
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.
42 */
43static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
44{
45 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
46
47 return (in_be32(mm_gc->regs + XGPIO_DATA_OFFSET) >> gpio) & 1;
48}
49
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.
55 *
56 * This function writes the specified value in to the specified signal of the
57 * GPIO device.
58 */
59static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
60{
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);
65
66 spin_lock_irqsave(&chip->gpio_lock, flags);
67
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);
74
75 spin_unlock_irqrestore(&chip->gpio_lock, flags);
76}
77
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.
82 *
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.
86 */
87static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
88{
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);
93
94 spin_lock_irqsave(&chip->gpio_lock, flags);
95
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);
99
100 spin_unlock_irqrestore(&chip->gpio_lock, flags);
101
102 return 0;
103}
104
105/**
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.
110 *
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.
114 */
115static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
116{
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);
121
122 spin_lock_irqsave(&chip->gpio_lock, flags);
123
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);
130
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);
134
135 spin_unlock_irqrestore(&chip->gpio_lock, flags);
136
137 return 0;
138}
139
140/**
141 * xgpio_save_regs - Set initial values of GPIO pins
142 * @mm_gc: pointer to memory mapped GPIO chip structure
143 */
144static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
145{
146 struct xgpio_instance *chip =
147 container_of(mm_gc, struct xgpio_instance, mmchip);
148
149 out_be32(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state);
150 out_be32(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir);
151}
152
153/**
154 * xgpio_of_probe - Probe method for the GPIO device.
155 * @np: pointer to device tree node
156 *
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.
160 */
161static int __devinit xgpio_of_probe(struct device_node *np)
162{
163 struct xgpio_instance *chip;
164 int status = 0;
165 const u32 *tree_info;
166
167 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
168 if (!chip)
169 return -ENOMEM;
170
171 /* Update GPIO state shadow register with default value */
172 tree_info = of_get_property(np, "xlnx,dout-default", NULL);
173 if (tree_info)
174 chip->gpio_state = be32_to_cpup(tree_info);
175
176 /* Update GPIO direction shadow register with default value */
177 chip->gpio_dir = 0xFFFFFFFF; /* By default, all pins are inputs */
178 tree_info = of_get_property(np, "xlnx,tri-default", NULL);
179 if (tree_info)
180 chip->gpio_dir = be32_to_cpup(tree_info);
181
182 /* Check device node and parent device node for device width */
183 chip->mmchip.gc.ngpio = 32; /* By default assume full GPIO controller */
184 tree_info = of_get_property(np, "xlnx,gpio-width", NULL);
185 if (!tree_info)
186 tree_info = of_get_property(np->parent,
187 "xlnx,gpio-width", NULL);
188 if (tree_info)
189 chip->mmchip.gc.ngpio = be32_to_cpup(tree_info);
190
191 spin_lock_init(&chip->gpio_lock);
192
193 chip->mmchip.gc.direction_input = xgpio_dir_in;
194 chip->mmchip.gc.direction_output = xgpio_dir_out;
195 chip->mmchip.gc.get = xgpio_get;
196 chip->mmchip.gc.set = xgpio_set;
197
198 chip->mmchip.save_regs = xgpio_save_regs;
199
200 /* Call the OF gpio helper to setup and register the GPIO device */
201 status = of_mm_gpiochip_add(np, &chip->mmchip);
202 if (status) {
203 kfree(chip);
204 pr_err("%s: error in probe function with status %d\n",
205 np->full_name, status);
206 return status;
207 }
208 pr_info("XGpio: %s: registered\n", np->full_name);
209 return 0;
210}
211
212static struct of_device_id xgpio_of_match[] __devinitdata = {
213 { .compatible = "xlnx,xps-gpio-1.00.a", },
214 { /* end of list */ },
215};
216
217static int __init xgpio_init(void)
218{
219 struct device_node *np;
220
221 for_each_matching_node(np, xgpio_of_match)
222 xgpio_of_probe(np);
223
224 return 0;
225}
226
227/* Make sure we get initialized before anyone else tries to use us */
228subsys_initcall(xgpio_init);
229/* No exit call at the moment as we cannot unregister of GPIO chips */
230
231MODULE_AUTHOR("Xilinx, Inc.");
232MODULE_DESCRIPTION("Xilinx GPIO driver");
233MODULE_LICENSE("GPL");
generated by cgit v1.2.2 (git 2.25.0) at 2025-04-26 05:44:12 -0400