tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for PCA9570 I2C GPO expander
4 *
5 * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
6 *
7 * Based on gpio-tpic2810.c
8 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
9 * Andrew F. Davis <afd@ti.com>
10 */
11
12#include <linux/gpio/driver.h>
13#include <linux/i2c.h>
14#include <linux/module.h>
15#include <linux/mutex.h>
16#include <linux/property.h>
17
18#define SLG7XL45106_GPO_REG 0xDB
19
20/**
21 * struct pca9570_chip_data - GPIO platformdata
22 * @ngpio: no of gpios
23 * @command: Command to be sent
24 */
25struct pca9570_chip_data {
26 u16 ngpio;
27 u32 command;
28};
29
30/**
31 * struct pca9570 - GPIO driver data
32 * @chip: GPIO controller chip
33 * @chip_data: GPIO controller platform data
34 * @lock: Protects write sequences
35 * @out: Buffer for device register
36 */
37struct pca9570 {
38 struct gpio_chip chip;
39 const struct pca9570_chip_data *chip_data;
40 struct mutex lock;
41 u8 out;
42};
43
44static int pca9570_read(struct pca9570 *gpio, u8 *value)
45{
46 struct i2c_client *client = to_i2c_client(gpio->chip.parent);
47 int ret;
48
49 if (gpio->chip_data->command != 0)
50 ret = i2c_smbus_read_byte_data(client, gpio->chip_data->command);
51 else
52 ret = i2c_smbus_read_byte(client);
53
54 if (ret < 0)
55 return ret;
56
57 *value = ret;
58 return 0;
59}
60
61static int pca9570_write(struct pca9570 *gpio, u8 value)
62{
63 struct i2c_client *client = to_i2c_client(gpio->chip.parent);
64
65 if (gpio->chip_data->command != 0)
66 return i2c_smbus_write_byte_data(client, gpio->chip_data->command, value);
67
68 return i2c_smbus_write_byte(client, value);
69}
70
71static int pca9570_get_direction(struct gpio_chip *chip,
72 unsigned offset)
73{
74 /* This device always output */
75 return GPIO_LINE_DIRECTION_OUT;
76}
77
78static int pca9570_get(struct gpio_chip *chip, unsigned offset)
79{
80 struct pca9570 *gpio = gpiochip_get_data(chip);
81 u8 buffer;
82 int ret;
83
84 ret = pca9570_read(gpio, &buffer);
85 if (ret)
86 return ret;
87
88 return !!(buffer & BIT(offset));
89}
90
91static int pca9570_set(struct gpio_chip *chip, unsigned int offset, int value)
92{
93 struct pca9570 *gpio = gpiochip_get_data(chip);
94 u8 buffer;
95 int ret;
96
97 mutex_lock(&gpio->lock);
98
99 buffer = gpio->out;
100 if (value)
101 buffer |= BIT(offset);
102 else
103 buffer &= ~BIT(offset);
104
105 ret = pca9570_write(gpio, buffer);
106 if (ret)
107 goto out;
108
109 gpio->out = buffer;
110
111out:
112 mutex_unlock(&gpio->lock);
113 return ret;
114}
115
116static int pca9570_probe(struct i2c_client *client)
117{
118 struct pca9570 *gpio;
119
120 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
121 if (!gpio)
122 return -ENOMEM;
123
124 gpio->chip.label = client->name;
125 gpio->chip.parent = &client->dev;
126 gpio->chip.owner = THIS_MODULE;
127 gpio->chip.get_direction = pca9570_get_direction;
128 gpio->chip.get = pca9570_get;
129 gpio->chip.set = pca9570_set;
130 gpio->chip.base = -1;
131 gpio->chip_data = device_get_match_data(&client->dev);
132 gpio->chip.ngpio = gpio->chip_data->ngpio;
133 gpio->chip.can_sleep = true;
134
135 mutex_init(&gpio->lock);
136
137 /* Read the current output level */
138 pca9570_read(gpio, &gpio->out);
139
140 i2c_set_clientdata(client, gpio);
141
142 return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
143}
144
145static const struct pca9570_chip_data pca9570_gpio = {
146 .ngpio = 4,
147};
148
149static const struct pca9570_chip_data pca9571_gpio = {
150 .ngpio = 8,
151};
152
153static const struct pca9570_chip_data slg7xl45106_gpio = {
154 .ngpio = 8,
155 .command = SLG7XL45106_GPO_REG,
156};
157
158static const struct i2c_device_id pca9570_id_table[] = {
159 { "pca9570", (kernel_ulong_t)&pca9570_gpio},
160 { "pca9571", (kernel_ulong_t)&pca9571_gpio },
161 { "slg7xl45106", (kernel_ulong_t)&slg7xl45106_gpio },
162 { /* sentinel */ }
163};
164MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
165
166static const struct of_device_id pca9570_of_match_table[] = {
167 { .compatible = "dlg,slg7xl45106", .data = &slg7xl45106_gpio},
168 { .compatible = "nxp,pca9570", .data = &pca9570_gpio },
169 { .compatible = "nxp,pca9571", .data = &pca9571_gpio },
170 { /* sentinel */ }
171};
172MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
173
174static struct i2c_driver pca9570_driver = {
175 .driver = {
176 .name = "pca9570",
177 .of_match_table = pca9570_of_match_table,
178 },
179 .probe = pca9570_probe,
180 .id_table = pca9570_id_table,
181};
182module_i2c_driver(pca9570_driver);
183
184MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
185MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
186MODULE_LICENSE("GPL v2");