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>
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 */
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;
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
59 static void xgpio_set(struct gpio_chip
*gc
, unsigned int gpio
, int val
)
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 */
70 chip
->gpio_state
|= 1 << gpio
;
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
);
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
)
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
);
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
)
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 */
126 chip
->gpio_state
|= 1 << gpio
;
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
);
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
;
166 const u32
*tree_info
;
168 chip
= kzalloc(sizeof(*chip
), GFP_KERNEL
);
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
);
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
);
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
);
188 tree_info
= of_get_property(np
->parent
,
189 "xlnx,gpio-width", NULL
);
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
);
207 pr_err("%s: error in probe function with status %d\n",
208 np
->full_name
, status
);
211 pr_info("XGpio: %s: registered\n", np
->full_name
);
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
)
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");