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
38static DEFINE_SPINLOCK(gpio_lock);
39
40static 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
51static 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
66static 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
79static 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
94static 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
114static struct platform_driver loongson_gpio_driver = {
115	.driver = {
116		.name = "loongson-gpio",
117	},
118	.probe = loongson_gpio_probe,
119};
120
121static 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}
135postcore_initcall(loongson_gpio_setup);
136