1 /*
2 * Generic PMC MSP71xx EXTENDED (EXD) GPIO handling. The extended gpio is
3 * a set of hardware registers that have no need for explicit locking as
4 * it is handled by unique method of writing individual set/clr bits.
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 as
8 * published by the Free Software Foundation.
9 *
10 * @author Patrick Glass <patrickglass@gmail.com>
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/gpio.h>
17 #include <linux/io.h>
18
19 #define MSP71XX_DATA_OFFSET(gpio) (2 * (gpio))
20 #define MSP71XX_READ_OFFSET(gpio) (MSP71XX_DATA_OFFSET(gpio) + 1)
21 #define MSP71XX_CFG_OUT_OFFSET(gpio) (MSP71XX_DATA_OFFSET(gpio) + 16)
22 #define MSP71XX_CFG_IN_OFFSET(gpio) (MSP71XX_CFG_OUT_OFFSET(gpio) + 1)
23
24 #define MSP71XX_EXD_GPIO_BASE 0x0BC000000L
25
26 #define to_msp71xx_exd_gpio_chip(c) \
27 container_of(c, struct msp71xx_exd_gpio_chip, chip)
28
29 /*
30 * struct msp71xx_exd_gpio_chip - container for gpio chip and registers
31 * @chip: chip structure for the specified gpio bank
32 * @reg: register for control and data of gpio pin
33 */
34 struct msp71xx_exd_gpio_chip {
35 struct gpio_chip chip;
36 void __iomem *reg;
37 };
38
39 /*
40 * msp71xx_exd_gpio_get() - return the chip's gpio value
41 * @chip: chip structure which controls the specified gpio
42 * @offset: gpio whose value will be returned
43 *
44 * It will return 0 if gpio value is low and other if high.
45 */
msp71xx_exd_gpio_get(struct gpio_chip * chip,unsigned offset)46 static int msp71xx_exd_gpio_get(struct gpio_chip *chip, unsigned offset)
47 {
48 struct msp71xx_exd_gpio_chip *msp71xx_chip =
49 to_msp71xx_exd_gpio_chip(chip);
50 const unsigned bit = MSP71XX_READ_OFFSET(offset);
51
52 return __raw_readl(msp71xx_chip->reg) & (1 << bit);
53 }
54
55 /*
56 * msp71xx_exd_gpio_set() - set the output value for the gpio
57 * @chip: chip structure who controls the specified gpio
58 * @offset: gpio whose value will be assigned
59 * @value: logic level to assign to the gpio initially
60 *
61 * This will set the gpio bit specified to the desired value. It will set the
62 * gpio pin low if value is 0 otherwise it will be high.
63 */
msp71xx_exd_gpio_set(struct gpio_chip * chip,unsigned offset,int value)64 static void msp71xx_exd_gpio_set(struct gpio_chip *chip,
65 unsigned offset, int value)
66 {
67 struct msp71xx_exd_gpio_chip *msp71xx_chip =
68 to_msp71xx_exd_gpio_chip(chip);
69 const unsigned bit = MSP71XX_DATA_OFFSET(offset);
70
71 __raw_writel(1 << (bit + (value ? 1 : 0)), msp71xx_chip->reg);
72 }
73
74 /*
75 * msp71xx_exd_direction_output() - declare the direction mode for a gpio
76 * @chip: chip structure which controls the specified gpio
77 * @offset: gpio whose value will be assigned
78 * @value: logic level to assign to the gpio initially
79 *
80 * This call will set the mode for the @gpio to output. It will set the
81 * gpio pin low if value is 0 otherwise it will be high.
82 */
msp71xx_exd_direction_output(struct gpio_chip * chip,unsigned offset,int value)83 static int msp71xx_exd_direction_output(struct gpio_chip *chip,
84 unsigned offset, int value)
85 {
86 struct msp71xx_exd_gpio_chip *msp71xx_chip =
87 to_msp71xx_exd_gpio_chip(chip);
88
89 msp71xx_exd_gpio_set(chip, offset, value);
90 __raw_writel(1 << MSP71XX_CFG_OUT_OFFSET(offset), msp71xx_chip->reg);
91 return 0;
92 }
93
94 /*
95 * msp71xx_exd_direction_input() - declare the direction mode for a gpio
96 * @chip: chip structure which controls the specified gpio
97 * @offset: gpio whose to which the value will be assigned
98 *
99 * This call will set the mode for the @gpio to input.
100 */
msp71xx_exd_direction_input(struct gpio_chip * chip,unsigned offset)101 static int msp71xx_exd_direction_input(struct gpio_chip *chip, unsigned offset)
102 {
103 struct msp71xx_exd_gpio_chip *msp71xx_chip =
104 to_msp71xx_exd_gpio_chip(chip);
105
106 __raw_writel(1 << MSP71XX_CFG_IN_OFFSET(offset), msp71xx_chip->reg);
107 return 0;
108 }
109
110 #define MSP71XX_EXD_GPIO_BANK(name, exd_reg, base_gpio, num_gpio) \
111 { \
112 .chip = { \
113 .label = name, \
114 .direction_input = msp71xx_exd_direction_input, \
115 .direction_output = msp71xx_exd_direction_output, \
116 .get = msp71xx_exd_gpio_get, \
117 .set = msp71xx_exd_gpio_set, \
118 .base = base_gpio, \
119 .ngpio = num_gpio, \
120 }, \
121 .reg = (void __iomem *)(MSP71XX_EXD_GPIO_BASE + exd_reg), \
122 }
123
124 /*
125 * struct msp71xx_exd_gpio_banks[] - container array of gpio banks
126 * @chip: chip structure for the specified gpio bank
127 * @reg: register for reading and writing the gpio pin value
128 *
129 * This array structure defines the extended gpio banks for the
130 * PMC MIPS Processor. We specify the bank name, the data/config
131 * register,the base starting gpio number, and the number of
132 * gpios exposed by the bank of gpios.
133 */
134 static struct msp71xx_exd_gpio_chip msp71xx_exd_gpio_banks[] = {
135
136 MSP71XX_EXD_GPIO_BANK("GPIO_23_16", 0x188, 16, 8),
137 MSP71XX_EXD_GPIO_BANK("GPIO_27_24", 0x18C, 24, 4),
138 };
139
msp71xx_init_gpio_extended(void)140 void __init msp71xx_init_gpio_extended(void)
141 {
142 int i;
143
144 for (i = 0; i < ARRAY_SIZE(msp71xx_exd_gpio_banks); i++)
145 gpiochip_add(&msp71xx_exd_gpio_banks[i].chip);
146 }
147