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Joachim Eastwood13a43fd2015-05-02 23:11:34 +02001/*
2 * GPIO driver for NXP LPC18xx/43xx.
3 *
4 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
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 */
11
12#include <linux/clk.h>
13#include <linux/gpio/driver.h>
14#include <linux/io.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/of_gpio.h>
18#include <linux/pinctrl/consumer.h>
19#include <linux/platform_device.h>
20
21/* LPC18xx GPIO register offsets */
22#define LPC18XX_REG_DIR(n) (0x2000 + n * sizeof(u32))
23
24#define LPC18XX_MAX_PORTS 8
25#define LPC18XX_PINS_PER_PORT 32
26
27struct lpc18xx_gpio_chip {
28 struct gpio_chip gpio;
29 void __iomem *base;
30 struct clk *clk;
31 spinlock_t lock;
32};
33
34static inline struct lpc18xx_gpio_chip *to_lpc18xx_gpio(struct gpio_chip *chip)
35{
36 return container_of(chip, struct lpc18xx_gpio_chip, gpio);
37}
38
Joachim Eastwood13a43fd2015-05-02 23:11:34 +020039static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
40{
41 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
42 writeb(value ? 1 : 0, gc->base + offset);
43}
44
45static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset)
46{
47 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
48 return !!readb(gc->base + offset);
49}
50
51static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset,
52 bool out)
53{
54 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip);
55 unsigned long flags;
56 u32 port, pin, dir;
57
58 port = offset / LPC18XX_PINS_PER_PORT;
59 pin = offset % LPC18XX_PINS_PER_PORT;
60
61 spin_lock_irqsave(&gc->lock, flags);
62 dir = readl(gc->base + LPC18XX_REG_DIR(port));
63 if (out)
64 dir |= BIT(pin);
65 else
66 dir &= ~BIT(pin);
67 writel(dir, gc->base + LPC18XX_REG_DIR(port));
68 spin_unlock_irqrestore(&gc->lock, flags);
69
70 return 0;
71}
72
73static int lpc18xx_gpio_direction_input(struct gpio_chip *chip,
74 unsigned offset)
75{
76 return lpc18xx_gpio_direction(chip, offset, false);
77}
78
79static int lpc18xx_gpio_direction_output(struct gpio_chip *chip,
80 unsigned offset, int value)
81{
82 lpc18xx_gpio_set(chip, offset, value);
83 return lpc18xx_gpio_direction(chip, offset, true);
84}
85
86static struct gpio_chip lpc18xx_chip = {
87 .label = "lpc18xx/43xx-gpio",
Jonas Gorski203f0da2015-10-11 17:34:16 +020088 .request = gpiochip_generic_request,
89 .free = gpiochip_generic_free,
Joachim Eastwood13a43fd2015-05-02 23:11:34 +020090 .direction_input = lpc18xx_gpio_direction_input,
91 .direction_output = lpc18xx_gpio_direction_output,
92 .set = lpc18xx_gpio_set,
93 .get = lpc18xx_gpio_get,
94 .ngpio = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT,
95 .owner = THIS_MODULE,
96};
97
98static int lpc18xx_gpio_probe(struct platform_device *pdev)
99{
100 struct lpc18xx_gpio_chip *gc;
101 struct resource *res;
102 int ret;
103
104 gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
105 if (!gc)
106 return -ENOMEM;
107
108 gc->gpio = lpc18xx_chip;
109 platform_set_drvdata(pdev, gc);
110
111 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
112 gc->base = devm_ioremap_resource(&pdev->dev, res);
113 if (IS_ERR(gc->base))
114 return PTR_ERR(gc->base);
115
116 gc->clk = devm_clk_get(&pdev->dev, NULL);
117 if (IS_ERR(gc->clk)) {
118 dev_err(&pdev->dev, "input clock not found\n");
119 return PTR_ERR(gc->clk);
120 }
121
122 ret = clk_prepare_enable(gc->clk);
123 if (ret) {
124 dev_err(&pdev->dev, "unable to enable clock\n");
125 return ret;
126 }
127
128 spin_lock_init(&gc->lock);
129
130 gc->gpio.dev = &pdev->dev;
131
132 ret = gpiochip_add(&gc->gpio);
133 if (ret) {
134 dev_err(&pdev->dev, "failed to add gpio chip\n");
135 clk_disable_unprepare(gc->clk);
136 return ret;
137 }
138
139 return 0;
140}
141
142static int lpc18xx_gpio_remove(struct platform_device *pdev)
143{
144 struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev);
145
146 gpiochip_remove(&gc->gpio);
147 clk_disable_unprepare(gc->clk);
148
149 return 0;
150}
151
152static const struct of_device_id lpc18xx_gpio_match[] = {
153 { .compatible = "nxp,lpc1850-gpio" },
154 { }
155};
156MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match);
157
158static struct platform_driver lpc18xx_gpio_driver = {
159 .probe = lpc18xx_gpio_probe,
160 .remove = lpc18xx_gpio_remove,
161 .driver = {
162 .name = "lpc18xx-gpio",
163 .of_match_table = lpc18xx_gpio_match,
164 },
165};
166module_platform_driver(lpc18xx_gpio_driver);
167
168MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
169MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx");
170MODULE_LICENSE("GPL v2");