1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Loongson-2F/3A/3B GPIO Support
4 *
5 * Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@st.com>
6 * Copyright (c) 2008-2010 Arnaud Patard <apatard@mandriva.com>
7 * Copyright (c) 2013 Hongbing Hu <huhb@lemote.com>
8 * Copyright (c) 2014 Huacai Chen <chenhc@lemote.com>
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/spinlock.h>
15 #include <linux/err.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/platform_device.h>
18 #include <linux/bitops.h>
19 #include <asm/types.h>
20 #include <loongson.h>
21
22 #define STLS2F_N_GPIO 4
23 #define STLS3A_N_GPIO 16
24
25 #ifdef CONFIG_CPU_LOONGSON64
26 #define LOONGSON_N_GPIO STLS3A_N_GPIO
27 #else
28 #define LOONGSON_N_GPIO STLS2F_N_GPIO
29 #endif
30
31 /*
32 * Offset into the register where we read lines, we write them from offset 0.
33 * This offset is the only thing that stand between us and using
34 * GPIO_GENERIC.
35 */
36 #define LOONGSON_GPIO_IN_OFFSET 16
37
38 static DEFINE_SPINLOCK(gpio_lock);
39
loongson_gpio_get_value(struct gpio_chip * chip,unsigned gpio)40 static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
41 {
42 u32 val;
43
44 spin_lock(&gpio_lock);
45 val = LOONGSON_GPIODATA;
46 spin_unlock(&gpio_lock);
47
48 return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
49 }
50
loongson_gpio_set_value(struct gpio_chip * chip,unsigned int gpio,int value)51 static int loongson_gpio_set_value(struct gpio_chip *chip, unsigned int gpio,
52 int value)
53 {
54 u32 val;
55
56 spin_lock(&gpio_lock);
57 val = LOONGSON_GPIODATA;
58 if (value)
59 val |= BIT(gpio);
60 else
61 val &= ~BIT(gpio);
62 LOONGSON_GPIODATA = val;
63 spin_unlock(&gpio_lock);
64
65 return 0;
66 }
67
loongson_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)68 static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
69 {
70 u32 temp;
71
72 spin_lock(&gpio_lock);
73 temp = LOONGSON_GPIOIE;
74 temp |= BIT(gpio);
75 LOONGSON_GPIOIE = temp;
76 spin_unlock(&gpio_lock);
77
78 return 0;
79 }
80
loongson_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)81 static int loongson_gpio_direction_output(struct gpio_chip *chip,
82 unsigned gpio, int level)
83 {
84 u32 temp;
85
86 loongson_gpio_set_value(chip, gpio, level);
87 spin_lock(&gpio_lock);
88 temp = LOONGSON_GPIOIE;
89 temp &= ~BIT(gpio);
90 LOONGSON_GPIOIE = temp;
91 spin_unlock(&gpio_lock);
92
93 return 0;
94 }
95
loongson_gpio_probe(struct platform_device * pdev)96 static int loongson_gpio_probe(struct platform_device *pdev)
97 {
98 struct gpio_chip *gc;
99 struct device *dev = &pdev->dev;
100
101 gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
102 if (!gc)
103 return -ENOMEM;
104
105 gc->label = "loongson-gpio-chip";
106 gc->base = 0;
107 gc->ngpio = LOONGSON_N_GPIO;
108 gc->get = loongson_gpio_get_value;
109 gc->set_rv = loongson_gpio_set_value;
110 gc->direction_input = loongson_gpio_direction_input;
111 gc->direction_output = loongson_gpio_direction_output;
112
113 return gpiochip_add_data(gc, NULL);
114 }
115
116 static struct platform_driver loongson_gpio_driver = {
117 .driver = {
118 .name = "loongson-gpio",
119 },
120 .probe = loongson_gpio_probe,
121 };
122
loongson_gpio_setup(void)123 static int __init loongson_gpio_setup(void)
124 {
125 struct platform_device *pdev;
126 int ret;
127
128 ret = platform_driver_register(&loongson_gpio_driver);
129 if (ret) {
130 pr_err("error registering loongson GPIO driver\n");
131 return ret;
132 }
133
134 pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);
135 return PTR_ERR_OR_ZERO(pdev);
136 }
137 postcore_initcall(loongson_gpio_setup);
138