summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-lpc18xx.c
blob: eb68603136b0e78e76d6a87b2739efac997f2538 (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
/*
 * GPIO driver for NXP LPC18xx/43xx.
 *
 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>

/* LPC18xx GPIO register offsets */
#define LPC18XX_REG_DIR(n)	(0x2000 + n * sizeof(u32))

#define LPC18XX_MAX_PORTS	8
#define LPC18XX_PINS_PER_PORT	32

struct lpc18xx_gpio_chip {
	struct gpio_chip gpio;
	void __iomem *base;
	struct clk *clk;
	spinlock_t lock;
};

static inline struct lpc18xx_gpio_chip *to_lpc18xx_gpio(struct gpio_chip *chip)
{
	return container_of(chip, struct lpc18xx_gpio_chip, gpio);
}

static int lpc18xx_gpio_request(struct gpio_chip *chip, unsigned offset)
{
	return pinctrl_request_gpio(offset);
}

static void lpc18xx_gpio_free(struct gpio_chip *chip, unsigned offset)
{
	pinctrl_free_gpio(offset);
}

static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
	struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
	writeb(value ? 1 : 0, gc->base + offset);
}

static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
{
	struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
	return !!readb(gc->base + offset);
}

static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
				  bool out)
{
	struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
	unsigned long flags;
	u32 port, pin, dir;

	port = offset / LPC18XX_PINS_PER_PORT;
	pin  = offset % LPC18XX_PINS_PER_PORT;

	spin_lock_irqsave(&gc->lock, flags);
	dir = readl(gc->base + LPC18XX_REG_DIR(port));
	if (out)
		dir |= BIT(pin);
	else
		dir &= ~BIT(pin);
	writel(dir, gc->base + LPC18XX_REG_DIR(port));
	spin_unlock_irqrestore(&gc->lock, flags);

	return 0;
}

static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
					unsigned offset)
{
	return lpc18xx_gpio_direction(chip, offset, false);
}

static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
					 unsigned offset, int value)
{
	lpc18xx_gpio_set(chip, offset, value);
	return lpc18xx_gpio_direction(chip, offset, true);
}

static struct gpio_chip lpc18xx_chip = {
	.label			= "lpc18xx/43xx-gpio",
	.request		= lpc18xx_gpio_request,
	.free			= lpc18xx_gpio_free,
	.direction_input	= lpc18xx_gpio_direction_input,
	.direction_output	= lpc18xx_gpio_direction_output,
	.set			= lpc18xx_gpio_set,
	.get			= lpc18xx_gpio_get,
	.ngpio			= LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
	.owner			= THIS_MODULE,
};

static int lpc18xx_gpio_probe(struct platform_device *pdev)
{
	struct lpc18xx_gpio_chip *gc;
	struct resource *res;
	int ret;

	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
	if (!gc)
		return -ENOMEM;

	gc->gpio = lpc18xx_chip;
	platform_set_drvdata(pdev, gc);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	gc->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(gc->base))
		return PTR_ERR(gc->base);

	gc->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(gc->clk)) {
		dev_err(&pdev->dev, "input clock not found\n");
		return PTR_ERR(gc->clk);
	}

	ret = clk_prepare_enable(gc->clk);
	if (ret) {
		dev_err(&pdev->dev, "unable to enable clock\n");
		return ret;
	}

	spin_lock_init(&gc->lock);

	gc->gpio.dev = &pdev->dev;

	ret = gpiochip_add(&gc->gpio);
	if (ret) {
		dev_err(&pdev->dev, "failed to add gpio chip\n");
		clk_disable_unprepare(gc->clk);
		return ret;
	}

	return 0;
}

static int lpc18xx_gpio_remove(struct platform_device *pdev)
{
	struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);

	gpiochip_remove(&gc->gpio);
	clk_disable_unprepare(gc->clk);

	return 0;
}

static const struct of_device_id lpc18xx_gpio_match[] = {
	{ .compatible = "nxp,lpc1850-gpio" },
	{ }
};
MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);

static struct platform_driver lpc18xx_gpio_driver = {
	.probe	= lpc18xx_gpio_probe,
	.remove	= lpc18xx_gpio_remove,
	.driver	= {
		.name		= "lpc18xx-gpio",
		.of_match_table	= lpc18xx_gpio_match,
	},
};
module_platform_driver(lpc18xx_gpio_driver);

MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
MODULE_LICENSE("GPL v2");