xref: /linux/drivers/gpio/gpio-loongson.c (revision bd628c1bed7902ec1f24ba0fe70758949146abbe)
1 /*
2  *  Loongson-2F/3A/3B GPIO Support
3  *
4  *  Copyright (c) 2008 Richard Liu,  STMicroelectronics	 <richard.liu@st.com>
5  *  Copyright (c) 2008-2010 Arnaud Patard <apatard@mandriva.com>
6  *  Copyright (c) 2013 Hongbing Hu <huhb@lemote.com>
7  *  Copyright (c) 2014 Huacai Chen <chenhc@lemote.com>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or
12  *  (at your option) any later version.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/spinlock.h>
19 #include <linux/err.h>
20 #include <linux/gpio/driver.h>
21 #include <linux/platform_device.h>
22 #include <linux/bitops.h>
23 #include <asm/types.h>
24 #include <loongson.h>
25 
26 #define STLS2F_N_GPIO		4
27 #define STLS3A_N_GPIO		16
28 
29 #ifdef CONFIG_CPU_LOONGSON3
30 #define LOONGSON_N_GPIO	STLS3A_N_GPIO
31 #else
32 #define LOONGSON_N_GPIO	STLS2F_N_GPIO
33 #endif
34 
35 /*
36  * Offset into the register where we read lines, we write them from offset 0.
37  * This offset is the only thing that stand between us and using
38  * GPIO_GENERIC.
39  */
40 #define LOONGSON_GPIO_IN_OFFSET	16
41 
42 static DEFINE_SPINLOCK(gpio_lock);
43 
44 static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
45 {
46 	u32 val;
47 
48 	spin_lock(&gpio_lock);
49 	val = LOONGSON_GPIODATA;
50 	spin_unlock(&gpio_lock);
51 
52 	return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
53 }
54 
55 static void loongson_gpio_set_value(struct gpio_chip *chip,
56 		unsigned gpio, int value)
57 {
58 	u32 val;
59 
60 	spin_lock(&gpio_lock);
61 	val = LOONGSON_GPIODATA;
62 	if (value)
63 		val |= BIT(gpio);
64 	else
65 		val &= ~BIT(gpio);
66 	LOONGSON_GPIODATA = val;
67 	spin_unlock(&gpio_lock);
68 }
69 
70 static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
71 {
72 	u32 temp;
73 
74 	spin_lock(&gpio_lock);
75 	temp = LOONGSON_GPIOIE;
76 	temp |= BIT(gpio);
77 	LOONGSON_GPIOIE = temp;
78 	spin_unlock(&gpio_lock);
79 
80 	return 0;
81 }
82 
83 static int loongson_gpio_direction_output(struct gpio_chip *chip,
84 		unsigned gpio, int level)
85 {
86 	u32 temp;
87 
88 	loongson_gpio_set_value(chip, gpio, level);
89 	spin_lock(&gpio_lock);
90 	temp = LOONGSON_GPIOIE;
91 	temp &= ~BIT(gpio);
92 	LOONGSON_GPIOIE = temp;
93 	spin_unlock(&gpio_lock);
94 
95 	return 0;
96 }
97 
98 static int loongson_gpio_probe(struct platform_device *pdev)
99 {
100 	struct gpio_chip *gc;
101 	struct device *dev = &pdev->dev;
102 
103 	gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
104 	if (!gc)
105 		return -ENOMEM;
106 
107 	gc->label = "loongson-gpio-chip";
108 	gc->base = 0;
109 	gc->ngpio = LOONGSON_N_GPIO;
110 	gc->get = loongson_gpio_get_value;
111 	gc->set = loongson_gpio_set_value;
112 	gc->direction_input = loongson_gpio_direction_input;
113 	gc->direction_output = loongson_gpio_direction_output;
114 
115 	return gpiochip_add_data(gc, NULL);
116 }
117 
118 static struct platform_driver loongson_gpio_driver = {
119 	.driver = {
120 		.name = "loongson-gpio",
121 	},
122 	.probe = loongson_gpio_probe,
123 };
124 
125 static int __init loongson_gpio_setup(void)
126 {
127 	struct platform_device *pdev;
128 	int ret;
129 
130 	ret = platform_driver_register(&loongson_gpio_driver);
131 	if (ret) {
132 		pr_err("error registering loongson GPIO driver\n");
133 		return ret;
134 	}
135 
136 	pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);
137 	return PTR_ERR_OR_ZERO(pdev);
138 }
139 postcore_initcall(loongson_gpio_setup);
140