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
loongson_gpio_get_value(struct gpio_chip * chip,unsigned gpio)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
loongson_gpio_set_value(struct gpio_chip * chip,unsigned gpio,int value)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
loongson_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)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
loongson_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)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
loongson_gpio_probe(struct platform_device * pdev)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
loongson_gpio_setup(void)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