ea53c192bc5f614387cb46ec6fe4aa9f400caf5f
[openwrt/svn-archive/archive.git] / target / linux / mcs814x / files-3.3 / drivers / gpio / gpio-mcs814x.c
1 /*
2 * Moschip MCS814x GPIO support
3 *
4 * Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
5 *
6 * Licensed under the GPLv2
7 */
8
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/platform_device.h>
14 #include <linux/gpio.h>
15 #include <linux/io.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18
19 struct mcs814x_gpio_chip {
20 void __iomem *regs;
21 struct gpio_chip chip;
22 };
23
24 #define GPIO_PIN 0x00
25 #define GPIO_DIR 0x04
26
27 #define to_mcs814x_gpio_chip(x) container_of(x, struct mcs814x_gpio_chip, chip)
28
29 static int mcs814x_gpio_get(struct gpio_chip *chip, unsigned offset)
30 {
31 struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
32
33 return __raw_readl(mcs814x->regs + GPIO_PIN) & (1 << offset);
34 }
35
36 static void mcs814x_gpio_set(struct gpio_chip *chip,
37 unsigned offset, int value)
38 {
39 struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
40 u32 mask;
41
42 mask = __raw_readl(mcs814x->regs + GPIO_PIN);
43 if (value)
44 mask |= (1 << offset);
45 else
46 mask &= ~(1 << offset);
47 __raw_writel(mask, mcs814x->regs + GPIO_PIN);
48 }
49
50 static int mcs814x_gpio_direction_output(struct gpio_chip *chip,
51 unsigned offset, int value)
52 {
53 struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
54 u32 mask;
55
56 mask = __raw_readl(mcs814x->regs + GPIO_DIR);
57 mask &= ~(1 << offset);
58 __raw_writel(mask, mcs814x->regs + GPIO_DIR);
59
60 return 0;
61 }
62
63 static int mcs814x_gpio_direction_input(struct gpio_chip *chip,
64 unsigned offset)
65 {
66 struct mcs814x_gpio_chip *mcs814x = to_mcs814x_gpio_chip(chip);
67 u32 mask;
68
69 mask = __raw_readl(mcs814x->regs + GPIO_DIR);
70 mask |= (1 << offset);
71 __raw_writel(mask, mcs814x->regs + GPIO_DIR);
72
73 return 0;
74 }
75
76 static int __devinit mcs814x_gpio_probe(struct platform_device *pdev)
77 {
78 struct resource *res;
79 struct mcs814x_gpio_chip *mcs814x_chip;
80 int ret;
81 const unsigned int *num_gpios;
82
83 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
84 if (!res)
85 return -ENODEV;
86
87 num_gpios = of_get_property(pdev->dev.of_node, "num-gpios", NULL);
88 if (!num_gpios)
89 dev_err(&pdev->dev, "FIXME: no num-gpios property\n");
90
91 mcs814x_chip = kzalloc(sizeof(*mcs814x_chip), GFP_KERNEL);
92 if (!mcs814x_chip)
93 return -ENOMEM;
94
95 mcs814x_chip->regs = devm_request_and_ioremap(&pdev->dev, res);
96 if (!mcs814x_chip->regs) {
97 ret = -ENOMEM;
98 goto out;
99 }
100
101 platform_set_drvdata(pdev, mcs814x_chip);
102
103 #ifdef CONFIG_OF_GPIO
104 mcs814x_chip->chip.of_node = pdev->dev.of_node;
105 #endif
106
107 mcs814x_chip->chip.label = pdev->name;
108 mcs814x_chip->chip.get = mcs814x_gpio_get;
109 mcs814x_chip->chip.set = mcs814x_gpio_set;
110 mcs814x_chip->chip.direction_input = mcs814x_gpio_direction_input;
111 mcs814x_chip->chip.direction_output = mcs814x_gpio_direction_output;
112 mcs814x_chip->chip.ngpio = be32_to_cpup(num_gpios);
113 /* we want dynamic base allocation */
114 mcs814x_chip->chip.base = -1;
115
116 ret = gpiochip_add(&mcs814x_chip->chip);
117 if (ret) {
118 dev_err(&pdev->dev, "failed to register gpiochip\n");
119 goto out;
120 }
121
122 return 0;
123
124 out:
125 platform_set_drvdata(pdev, NULL);
126 kfree(mcs814x_chip);
127 return ret;
128 }
129
130 static struct of_device_id mcs814x_gpio_ids[] __devinitdata = {
131 { .compatible = "moschip,mcs814x-gpio" },
132 { /* sentinel */ },
133 };
134
135 static struct platform_driver mcs814x_gpio_driver = {
136 .driver = {
137 .name = "mcs814x-gpio",
138 .owner = THIS_MODULE,
139 .of_match_table = mcs814x_gpio_ids,
140 },
141 .probe = mcs814x_gpio_probe,
142 };
143
144 int __init mcs814x_gpio_init(void)
145 {
146 return platform_driver_register(&mcs814x_gpio_driver);
147 }
148 postcore_initcall(mcs814x_gpio_init);