summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpio-syscon.c
blob: 30884fbc750de5e74f7322a415bfab7650185e2d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
/*
 *  SYSCON GPIO driver
 *
 *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/syscon.h>

#define GPIO_SYSCON_FEAT_IN	BIT(0)
#define GPIO_SYSCON_FEAT_OUT	BIT(1)
#define GPIO_SYSCON_FEAT_DIR	BIT(2)

/* SYSCON driver is designed to use 32-bit wide registers */
#define SYSCON_REG_SIZE		(4)
#define SYSCON_REG_BITS		(SYSCON_REG_SIZE * 8)

/**
 * struct syscon_gpio_data - Configuration for the device.
 * compatible:		SYSCON driver compatible string.
 * flags:		Set of GPIO_SYSCON_FEAT_ flags:
 *			GPIO_SYSCON_FEAT_IN:	GPIOs supports input,
 *			GPIO_SYSCON_FEAT_OUT:	GPIOs supports output,
 *			GPIO_SYSCON_FEAT_DIR:	GPIOs supports switch direction.
 * bit_count:		Number of bits used as GPIOs.
 * dat_bit_offset:	Offset (in bits) to the first GPIO bit.
 * dir_bit_offset:	Optional offset (in bits) to the first bit to switch
 *			GPIO direction (Used with GPIO_SYSCON_FEAT_DIR flag).
 */

struct syscon_gpio_data {
	const char	*compatible;
	unsigned int	flags;
	unsigned int	bit_count;
	unsigned int	dat_bit_offset;
	unsigned int	dir_bit_offset;
};

struct syscon_gpio_priv {
	struct gpio_chip		chip;
	struct regmap			*syscon;
	const struct syscon_gpio_data	*data;
};

static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip)
{
	return container_of(chip, struct syscon_gpio_priv, chip);
}

static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
	unsigned int val, offs = priv->data->dat_bit_offset + offset;
	int ret;

	ret = regmap_read(priv->syscon,
			  (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);
	if (ret)
		return ret;

	return !!(val & BIT(offs % SYSCON_REG_BITS));
}

static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
	struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
	unsigned int offs = priv->data->dat_bit_offset + offset;

	regmap_update_bits(priv->syscon,
			   (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
			   BIT(offs % SYSCON_REG_BITS),
			   val ? BIT(offs % SYSCON_REG_BITS) : 0);
}

static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
{
	struct syscon_gpio_priv *priv = to_syscon_gpio(chip);

	if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
		unsigned int offs = priv->data->dir_bit_offset + offset;

		regmap_update_bits(priv->syscon,
				   (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
				   BIT(offs % SYSCON_REG_BITS), 0);
	}

	return 0;
}

static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val)
{
	struct syscon_gpio_priv *priv = to_syscon_gpio(chip);

	if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
		unsigned int offs = priv->data->dir_bit_offset + offset;

		regmap_update_bits(priv->syscon,
				   (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
				   BIT(offs % SYSCON_REG_BITS),
				   BIT(offs % SYSCON_REG_BITS));
	}

	syscon_gpio_set(chip, offset, val);

	return 0;
}

static const struct syscon_gpio_data clps711x_mctrl_gpio = {
	/* ARM CLPS711X SYSFLG1 Bits 8-10 */
	.compatible	= "cirrus,clps711x-syscon1",
	.flags		= GPIO_SYSCON_FEAT_IN,
	.bit_count	= 3,
	.dat_bit_offset	= 0x40 * 8 + 8,
};

static const struct of_device_id syscon_gpio_ids[] = {
	{
		.compatible	= "cirrus,clps711x-mctrl-gpio",
		.data		= &clps711x_mctrl_gpio,
	},
	{ }
};
MODULE_DEVICE_TABLE(of, syscon_gpio_ids);

static int syscon_gpio_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	const struct of_device_id *of_id = of_match_device(syscon_gpio_ids, dev);
	struct syscon_gpio_priv *priv;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->data = of_id->data;

	priv->syscon =
		syscon_regmap_lookup_by_compatible(priv->data->compatible);
	if (IS_ERR(priv->syscon))
		return PTR_ERR(priv->syscon);

	priv->chip.dev = dev;
	priv->chip.owner = THIS_MODULE;
	priv->chip.label = dev_name(dev);
	priv->chip.base = -1;
	priv->chip.ngpio = priv->data->bit_count;
	priv->chip.get = syscon_gpio_get;
	if (priv->data->flags & GPIO_SYSCON_FEAT_IN)
		priv->chip.direction_input = syscon_gpio_dir_in;
	if (priv->data->flags & GPIO_SYSCON_FEAT_OUT) {
		priv->chip.set = syscon_gpio_set;
		priv->chip.direction_output = syscon_gpio_dir_out;
	}

	platform_set_drvdata(pdev, priv);

	return gpiochip_add(&priv->chip);
}

static int syscon_gpio_remove(struct platform_device *pdev)
{
	struct syscon_gpio_priv *priv = platform_get_drvdata(pdev);

	gpiochip_remove(&priv->chip);
	return 0;
}

static struct platform_driver syscon_gpio_driver = {
	.driver	= {
		.name		= "gpio-syscon",
		.owner		= THIS_MODULE,
		.of_match_table	= syscon_gpio_ids,
	},
	.probe	= syscon_gpio_probe,
	.remove	= syscon_gpio_remove,
};
module_platform_driver(syscon_gpio_driver);

MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("SYSCON GPIO driver");
MODULE_LICENSE("GPL");