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 | |
40 | static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio) |
41 | { |
42 | u32 val; |
43 | |
44 | spin_lock(lock: &gpio_lock); |
45 | val = LOONGSON_GPIODATA; |
46 | spin_unlock(lock: &gpio_lock); |
47 | |
48 | return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET)); |
49 | } |
50 | |
51 | static void loongson_gpio_set_value(struct gpio_chip *chip, |
52 | unsigned gpio, int value) |
53 | { |
54 | u32 val; |
55 | |
56 | spin_lock(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(lock: &gpio_lock); |
64 | } |
65 | |
66 | static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio) |
67 | { |
68 | u32 temp; |
69 | |
70 | spin_lock(lock: &gpio_lock); |
71 | temp = LOONGSON_GPIOIE; |
72 | temp |= BIT(gpio); |
73 | LOONGSON_GPIOIE = temp; |
74 | spin_unlock(lock: &gpio_lock); |
75 | |
76 | return 0; |
77 | } |
78 | |
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, value: level); |
85 | spin_lock(lock: &gpio_lock); |
86 | temp = LOONGSON_GPIOIE; |
87 | temp &= ~BIT(gpio); |
88 | LOONGSON_GPIOIE = temp; |
89 | spin_unlock(lock: &gpio_lock); |
90 | |
91 | return 0; |
92 | } |
93 | |
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, size: 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 | |
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(name: "loongson-gpio" , id: -1, NULL, num: 0); |
133 | return PTR_ERR_OR_ZERO(ptr: pdev); |
134 | } |
135 | postcore_initcall(loongson_gpio_setup); |
136 | |