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Alexander Shiyan6a8a0c12014-03-11 21:55:14 +04001/*
2 * SYSCON GPIO driver
3 *
4 * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
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 as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12#include <linux/err.h>
13#include <linux/gpio.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/platform_device.h>
18#include <linux/regmap.h>
19#include <linux/mfd/syscon.h>
20
21#define GPIO_SYSCON_FEAT_IN BIT(0)
22#define GPIO_SYSCON_FEAT_OUT BIT(1)
23#define GPIO_SYSCON_FEAT_DIR BIT(2)
24
25/* SYSCON driver is designed to use 32-bit wide registers */
26#define SYSCON_REG_SIZE (4)
27#define SYSCON_REG_BITS (SYSCON_REG_SIZE * 8)
28
29/**
30 * struct syscon_gpio_data - Configuration for the device.
31 * compatible: SYSCON driver compatible string.
32 * flags: Set of GPIO_SYSCON_FEAT_ flags:
33 * GPIO_SYSCON_FEAT_IN: GPIOs supports input,
34 * GPIO_SYSCON_FEAT_OUT: GPIOs supports output,
35 * GPIO_SYSCON_FEAT_DIR: GPIOs supports switch direction.
36 * bit_count: Number of bits used as GPIOs.
37 * dat_bit_offset: Offset (in bits) to the first GPIO bit.
38 * dir_bit_offset: Optional offset (in bits) to the first bit to switch
39 * GPIO direction (Used with GPIO_SYSCON_FEAT_DIR flag).
40 */
41
42struct syscon_gpio_data {
43 const char *compatible;
44 unsigned int flags;
45 unsigned int bit_count;
46 unsigned int dat_bit_offset;
47 unsigned int dir_bit_offset;
48};
49
50struct syscon_gpio_priv {
51 struct gpio_chip chip;
52 struct regmap *syscon;
53 const struct syscon_gpio_data *data;
54};
55
56static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip)
57{
58 return container_of(chip, struct syscon_gpio_priv, chip);
59}
60
61static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
62{
63 struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
64 unsigned int val, offs = priv->data->dat_bit_offset + offset;
65 int ret;
66
67 ret = regmap_read(priv->syscon,
68 (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);
69 if (ret)
70 return ret;
71
72 return !!(val & BIT(offs % SYSCON_REG_BITS));
73}
74
75static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
76{
77 struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
78 unsigned int offs = priv->data->dat_bit_offset + offset;
79
80 regmap_update_bits(priv->syscon,
81 (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
82 BIT(offs % SYSCON_REG_BITS),
83 val ? BIT(offs % SYSCON_REG_BITS) : 0);
84}
85
86static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
87{
88 struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
89
90 if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
91 unsigned int offs = priv->data->dir_bit_offset + offset;
92
93 regmap_update_bits(priv->syscon,
94 (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
95 BIT(offs % SYSCON_REG_BITS), 0);
96 }
97
98 return 0;
99}
100
101static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val)
102{
103 struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
104
105 if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
106 unsigned int offs = priv->data->dir_bit_offset + offset;
107
108 regmap_update_bits(priv->syscon,
109 (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
110 BIT(offs % SYSCON_REG_BITS),
111 BIT(offs % SYSCON_REG_BITS));
112 }
113
114 syscon_gpio_set(chip, offset, val);
115
116 return 0;
117}
118
119static const struct syscon_gpio_data clps711x_mctrl_gpio = {
120 /* ARM CLPS711X SYSFLG1 Bits 8-10 */
121 .compatible = "cirrus,clps711x-syscon1",
122 .flags = GPIO_SYSCON_FEAT_IN,
123 .bit_count = 3,
124 .dat_bit_offset = 0x40 * 8 + 8,
125};
126
127static const struct of_device_id syscon_gpio_ids[] = {
128 {
129 .compatible = "cirrus,clps711x-mctrl-gpio",
130 .data = &clps711x_mctrl_gpio,
131 },
132 { }
133};
134MODULE_DEVICE_TABLE(of, syscon_gpio_ids);
135
136static int syscon_gpio_probe(struct platform_device *pdev)
137{
138 struct device *dev = &pdev->dev;
139 const struct of_device_id *of_id = of_match_device(syscon_gpio_ids, dev);
140 struct syscon_gpio_priv *priv;
141
142 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
143 if (!priv)
144 return -ENOMEM;
145
146 priv->data = of_id->data;
147
148 priv->syscon =
149 syscon_regmap_lookup_by_compatible(priv->data->compatible);
150 if (IS_ERR(priv->syscon))
151 return PTR_ERR(priv->syscon);
152
153 priv->chip.dev = dev;
154 priv->chip.owner = THIS_MODULE;
155 priv->chip.label = dev_name(dev);
156 priv->chip.base = -1;
157 priv->chip.ngpio = priv->data->bit_count;
158 priv->chip.get = syscon_gpio_get;
159 if (priv->data->flags & GPIO_SYSCON_FEAT_IN)
160 priv->chip.direction_input = syscon_gpio_dir_in;
161 if (priv->data->flags & GPIO_SYSCON_FEAT_OUT) {
162 priv->chip.set = syscon_gpio_set;
163 priv->chip.direction_output = syscon_gpio_dir_out;
164 }
165
166 platform_set_drvdata(pdev, priv);
167
168 return gpiochip_add(&priv->chip);
169}
170
171static int syscon_gpio_remove(struct platform_device *pdev)
172{
173 struct syscon_gpio_priv *priv = platform_get_drvdata(pdev);
174
175 return gpiochip_remove(&priv->chip);
176}
177
178static struct platform_driver syscon_gpio_driver = {
179 .driver = {
180 .name = "gpio-syscon",
181 .owner = THIS_MODULE,
182 .of_match_table = syscon_gpio_ids,
183 },
184 .probe = syscon_gpio_probe,
185 .remove = syscon_gpio_remove,
186};
187module_platform_driver(syscon_gpio_driver);
188
189MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
190MODULE_DESCRIPTION("SYSCON GPIO driver");
191MODULE_LICENSE("GPL");