1 /* arch/arm/plat-samsung/gpiolib.c
2 *
3 * Copyright 2008 Openmoko, Inc.
4 * Copyright 2008 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>
6 * http://armlinux.simtec.co.uk/
7 *
8 * Copyright (c) 2009 Samsung Electronics Co., Ltd.
9 * http://www.samsung.com/
10 *
11 * SAMSUNG - GPIOlib support
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17
18 #include <linux/kernel.h>
19 #include <linux/irq.h>
20 #include <linux/io.h>
21 #include <linux/gpio.h>
22 #include <plat/gpio-core.h>
23 #include <plat/gpio-cfg.h>
24 #include <plat/gpio-cfg-helpers.h>
25
26 #ifndef DEBUG_GPIO
27 #define gpio_dbg(x...) do { } while (0)
28 #else
29 #define gpio_dbg(x...) printk(KERN_DEBUG x)
30 #endif
31
32 /* The samsung_gpiolib_4bit routines are to control the gpio banks where
33 * the gpio configuration register (GPxCON) has 4 bits per GPIO, as the
34 * following example:
35 *
36 * base + 0x00: Control register, 4 bits per gpio
37 * gpio n: 4 bits starting at (4*n)
38 * 0000 = input, 0001 = output, others mean special-function
39 * base + 0x04: Data register, 1 bit per gpio
40 * bit n: data bit n
41 *
42 * Note, since the data register is one bit per gpio and is at base + 0x4
43 * we can use s3c_gpiolib_get and s3c_gpiolib_set to change the state of
44 * the output.
45 */
46
samsung_gpiolib_4bit_input(struct gpio_chip * chip,unsigned int offset)47 static int samsung_gpiolib_4bit_input(struct gpio_chip *chip,
48 unsigned int offset)
49 {
50 struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
51 void __iomem *base = ourchip->base;
52 unsigned long con;
53
54 con = __raw_readl(base + GPIOCON_OFF);
55 con &= ~(0xf << con_4bit_shift(offset));
56 __raw_writel(con, base + GPIOCON_OFF);
57
58 gpio_dbg("%s: %p: CON now %08lx\n", __func__, base, con);
59
60 return 0;
61 }
62
samsung_gpiolib_4bit_output(struct gpio_chip * chip,unsigned int offset,int value)63 static int samsung_gpiolib_4bit_output(struct gpio_chip *chip,
64 unsigned int offset, int value)
65 {
66 struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
67 void __iomem *base = ourchip->base;
68 unsigned long con;
69 unsigned long dat;
70
71 con = __raw_readl(base + GPIOCON_OFF);
72 con &= ~(0xf << con_4bit_shift(offset));
73 con |= 0x1 << con_4bit_shift(offset);
74
75 dat = __raw_readl(base + GPIODAT_OFF);
76
77 if (value)
78 dat |= 1 << offset;
79 else
80 dat &= ~(1 << offset);
81
82 __raw_writel(dat, base + GPIODAT_OFF);
83 __raw_writel(con, base + GPIOCON_OFF);
84 __raw_writel(dat, base + GPIODAT_OFF);
85
86 gpio_dbg("%s: %p: CON %08lx, DAT %08lx\n", __func__, base, con, dat);
87
88 return 0;
89 }
90
91 /* The next set of routines are for the case where the GPIO configuration
92 * registers are 4 bits per GPIO but there is more than one register (the
93 * bank has more than 8 GPIOs.
94 *
95 * This case is the similar to the 4 bit case, but the registers are as
96 * follows:
97 *
98 * base + 0x00: Control register, 4 bits per gpio (lower 8 GPIOs)
99 * gpio n: 4 bits starting at (4*n)
100 * 0000 = input, 0001 = output, others mean special-function
101 * base + 0x04: Control register, 4 bits per gpio (up to 8 additions GPIOs)
102 * gpio n: 4 bits starting at (4*n)
103 * 0000 = input, 0001 = output, others mean special-function
104 * base + 0x08: Data register, 1 bit per gpio
105 * bit n: data bit n
106 *
107 * To allow us to use the s3c_gpiolib_get and s3c_gpiolib_set routines we
108 * store the 'base + 0x4' address so that these routines see the data
109 * register at ourchip->base + 0x04.
110 */
111
samsung_gpiolib_4bit2_input(struct gpio_chip * chip,unsigned int offset)112 static int samsung_gpiolib_4bit2_input(struct gpio_chip *chip,
113 unsigned int offset)
114 {
115 struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
116 void __iomem *base = ourchip->base;
117 void __iomem *regcon = base;
118 unsigned long con;
119
120 if (offset > 7)
121 offset -= 8;
122 else
123 regcon -= 4;
124
125 con = __raw_readl(regcon);
126 con &= ~(0xf << con_4bit_shift(offset));
127 __raw_writel(con, regcon);
128
129 gpio_dbg("%s: %p: CON %08lx\n", __func__, base, con);
130
131 return 0;
132 }
133
samsung_gpiolib_4bit2_output(struct gpio_chip * chip,unsigned int offset,int value)134 static int samsung_gpiolib_4bit2_output(struct gpio_chip *chip,
135 unsigned int offset, int value)
136 {
137 struct s3c_gpio_chip *ourchip = to_s3c_gpio(chip);
138 void __iomem *base = ourchip->base;
139 void __iomem *regcon = base;
140 unsigned long con;
141 unsigned long dat;
142 unsigned con_offset = offset;
143
144 if (con_offset > 7)
145 con_offset -= 8;
146 else
147 regcon -= 4;
148
149 con = __raw_readl(regcon);
150 con &= ~(0xf << con_4bit_shift(con_offset));
151 con |= 0x1 << con_4bit_shift(con_offset);
152
153 dat = __raw_readl(base + GPIODAT_OFF);
154
155 if (value)
156 dat |= 1 << offset;
157 else
158 dat &= ~(1 << offset);
159
160 __raw_writel(dat, base + GPIODAT_OFF);
161 __raw_writel(con, regcon);
162 __raw_writel(dat, base + GPIODAT_OFF);
163
164 gpio_dbg("%s: %p: CON %08lx, DAT %08lx\n", __func__, base, con, dat);
165
166 return 0;
167 }
168
samsung_gpiolib_add_4bit(struct s3c_gpio_chip * chip)169 void __init samsung_gpiolib_add_4bit(struct s3c_gpio_chip *chip)
170 {
171 chip->chip.direction_input = samsung_gpiolib_4bit_input;
172 chip->chip.direction_output = samsung_gpiolib_4bit_output;
173 chip->pm = __gpio_pm(&s3c_gpio_pm_4bit);
174 }
175
samsung_gpiolib_add_4bit2(struct s3c_gpio_chip * chip)176 void __init samsung_gpiolib_add_4bit2(struct s3c_gpio_chip *chip)
177 {
178 chip->chip.direction_input = samsung_gpiolib_4bit2_input;
179 chip->chip.direction_output = samsung_gpiolib_4bit2_output;
180 chip->pm = __gpio_pm(&s3c_gpio_pm_4bit);
181 }
182
samsung_gpiolib_add_4bit_chips(struct s3c_gpio_chip * chip,int nr_chips)183 void __init samsung_gpiolib_add_4bit_chips(struct s3c_gpio_chip *chip,
184 int nr_chips)
185 {
186 for (; nr_chips > 0; nr_chips--, chip++) {
187 samsung_gpiolib_add_4bit(chip);
188 s3c_gpiolib_add(chip);
189 }
190 }
191
samsung_gpiolib_add_4bit2_chips(struct s3c_gpio_chip * chip,int nr_chips)192 void __init samsung_gpiolib_add_4bit2_chips(struct s3c_gpio_chip *chip,
193 int nr_chips)
194 {
195 for (; nr_chips > 0; nr_chips--, chip++) {
196 samsung_gpiolib_add_4bit2(chip);
197 s3c_gpiolib_add(chip);
198 }
199 }
200
samsung_gpiolib_add_2bit_chips(struct s3c_gpio_chip * chip,int nr_chips)201 void __init samsung_gpiolib_add_2bit_chips(struct s3c_gpio_chip *chip,
202 int nr_chips)
203 {
204 for (; nr_chips > 0; nr_chips--, chip++)
205 s3c_gpiolib_add(chip);
206 }
207