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 gpio,int value)51 static void loongson_gpio_set_value(struct gpio_chip *chip,
52 		unsigned gpio, 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 
loongson_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)66 static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
67 {
68 	u32 temp;
69 
70 	spin_lock(&gpio_lock);
71 	temp = LOONGSON_GPIOIE;
72 	temp |= BIT(gpio);
73 	LOONGSON_GPIOIE = temp;
74 	spin_unlock(&gpio_lock);
75 
76 	return 0;
77 }
78 
loongson_gpio_direction_output(struct gpio_chip * chip,unsigned gpio,int level)79 static int loongson_gpio_direction_output(struct gpio_chip *chip,
80 		unsigned gpio, int level)
81 {
82 	u32 temp;
83 
84 	loongson_gpio_set_value(chip, gpio, level);
85 	spin_lock(&gpio_lock);
86 	temp = LOONGSON_GPIOIE;
87 	temp &= ~BIT(gpio);
88 	LOONGSON_GPIOIE = temp;
89 	spin_unlock(&gpio_lock);
90 
91 	return 0;
92 }
93 
loongson_gpio_probe(struct platform_device * pdev)94 static int loongson_gpio_probe(struct platform_device *pdev)
95 {
96 	struct gpio_chip *gc;
97 	struct device *dev = &pdev->dev;
98 
99 	gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
100 	if (!gc)
101 		return -ENOMEM;
102 
103 	gc->label = "loongson-gpio-chip";
104 	gc->base = 0;
105 	gc->ngpio = LOONGSON_N_GPIO;
106 	gc->get = loongson_gpio_get_value;
107 	gc->set = loongson_gpio_set_value;
108 	gc->direction_input = loongson_gpio_direction_input;
109 	gc->direction_output = loongson_gpio_direction_output;
110 
111 	return gpiochip_add_data(gc, NULL);
112 }
113 
114 static struct platform_driver loongson_gpio_driver = {
115 	.driver = {
116 		.name = "loongson-gpio",
117 	},
118 	.probe = loongson_gpio_probe,
119 };
120 
loongson_gpio_setup(void)121 static int __init loongson_gpio_setup(void)
122 {
123 	struct platform_device *pdev;
124 	int ret;
125 
126 	ret = platform_driver_register(&loongson_gpio_driver);
127 	if (ret) {
128 		pr_err("error registering loongson GPIO driver\n");
129 		return ret;
130 	}
131 
132 	pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);
133 	return PTR_ERR_OR_ZERO(pdev);
134 }
135 postcore_initcall(loongson_gpio_setup);
136