1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Driver for PCA9570 I2C GPO expander
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Based on gpio-tpic2810.c
8*4882a593Smuzhiyun * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
9*4882a593Smuzhiyun * Andrew F. Davis <afd@ti.com>
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/gpio/driver.h>
13*4882a593Smuzhiyun #include <linux/i2c.h>
14*4882a593Smuzhiyun #include <linux/module.h>
15*4882a593Smuzhiyun #include <linux/mutex.h>
16*4882a593Smuzhiyun #include <linux/property.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun /**
19*4882a593Smuzhiyun * struct pca9570 - GPIO driver data
20*4882a593Smuzhiyun * @chip: GPIO controller chip
21*4882a593Smuzhiyun * @lock: Protects write sequences
22*4882a593Smuzhiyun * @out: Buffer for device register
23*4882a593Smuzhiyun */
24*4882a593Smuzhiyun struct pca9570 {
25*4882a593Smuzhiyun struct gpio_chip chip;
26*4882a593Smuzhiyun struct mutex lock;
27*4882a593Smuzhiyun u8 out;
28*4882a593Smuzhiyun };
29*4882a593Smuzhiyun
pca9570_read(struct pca9570 * gpio,u8 * value)30*4882a593Smuzhiyun static int pca9570_read(struct pca9570 *gpio, u8 *value)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun struct i2c_client *client = to_i2c_client(gpio->chip.parent);
33*4882a593Smuzhiyun int ret;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun ret = i2c_smbus_read_byte(client);
36*4882a593Smuzhiyun if (ret < 0)
37*4882a593Smuzhiyun return ret;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun *value = ret;
40*4882a593Smuzhiyun return 0;
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
pca9570_write(struct pca9570 * gpio,u8 value)43*4882a593Smuzhiyun static int pca9570_write(struct pca9570 *gpio, u8 value)
44*4882a593Smuzhiyun {
45*4882a593Smuzhiyun struct i2c_client *client = to_i2c_client(gpio->chip.parent);
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun return i2c_smbus_write_byte(client, value);
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun
pca9570_get_direction(struct gpio_chip * chip,unsigned offset)50*4882a593Smuzhiyun static int pca9570_get_direction(struct gpio_chip *chip,
51*4882a593Smuzhiyun unsigned offset)
52*4882a593Smuzhiyun {
53*4882a593Smuzhiyun /* This device always output */
54*4882a593Smuzhiyun return GPIO_LINE_DIRECTION_OUT;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
pca9570_get(struct gpio_chip * chip,unsigned offset)57*4882a593Smuzhiyun static int pca9570_get(struct gpio_chip *chip, unsigned offset)
58*4882a593Smuzhiyun {
59*4882a593Smuzhiyun struct pca9570 *gpio = gpiochip_get_data(chip);
60*4882a593Smuzhiyun u8 buffer;
61*4882a593Smuzhiyun int ret;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun ret = pca9570_read(gpio, &buffer);
64*4882a593Smuzhiyun if (ret)
65*4882a593Smuzhiyun return ret;
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun return !!(buffer & BIT(offset));
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
pca9570_set(struct gpio_chip * chip,unsigned offset,int value)70*4882a593Smuzhiyun static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value)
71*4882a593Smuzhiyun {
72*4882a593Smuzhiyun struct pca9570 *gpio = gpiochip_get_data(chip);
73*4882a593Smuzhiyun u8 buffer;
74*4882a593Smuzhiyun int ret;
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun mutex_lock(&gpio->lock);
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun buffer = gpio->out;
79*4882a593Smuzhiyun if (value)
80*4882a593Smuzhiyun buffer |= BIT(offset);
81*4882a593Smuzhiyun else
82*4882a593Smuzhiyun buffer &= ~BIT(offset);
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun ret = pca9570_write(gpio, buffer);
85*4882a593Smuzhiyun if (ret)
86*4882a593Smuzhiyun goto out;
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun gpio->out = buffer;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun out:
91*4882a593Smuzhiyun mutex_unlock(&gpio->lock);
92*4882a593Smuzhiyun }
93*4882a593Smuzhiyun
pca9570_probe(struct i2c_client * client)94*4882a593Smuzhiyun static int pca9570_probe(struct i2c_client *client)
95*4882a593Smuzhiyun {
96*4882a593Smuzhiyun struct pca9570 *gpio;
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
99*4882a593Smuzhiyun if (!gpio)
100*4882a593Smuzhiyun return -ENOMEM;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun gpio->chip.label = client->name;
103*4882a593Smuzhiyun gpio->chip.parent = &client->dev;
104*4882a593Smuzhiyun gpio->chip.owner = THIS_MODULE;
105*4882a593Smuzhiyun gpio->chip.get_direction = pca9570_get_direction;
106*4882a593Smuzhiyun gpio->chip.get = pca9570_get;
107*4882a593Smuzhiyun gpio->chip.set = pca9570_set;
108*4882a593Smuzhiyun gpio->chip.base = -1;
109*4882a593Smuzhiyun gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev);
110*4882a593Smuzhiyun gpio->chip.can_sleep = true;
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun mutex_init(&gpio->lock);
113*4882a593Smuzhiyun
114*4882a593Smuzhiyun /* Read the current output level */
115*4882a593Smuzhiyun pca9570_read(gpio, &gpio->out);
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun i2c_set_clientdata(client, gpio);
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
120*4882a593Smuzhiyun }
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun static const struct i2c_device_id pca9570_id_table[] = {
123*4882a593Smuzhiyun { "pca9570", 4 },
124*4882a593Smuzhiyun { /* sentinel */ }
125*4882a593Smuzhiyun };
126*4882a593Smuzhiyun MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
127*4882a593Smuzhiyun
128*4882a593Smuzhiyun static const struct of_device_id pca9570_of_match_table[] = {
129*4882a593Smuzhiyun { .compatible = "nxp,pca9570", .data = (void *)4 },
130*4882a593Smuzhiyun { /* sentinel */ }
131*4882a593Smuzhiyun };
132*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
133*4882a593Smuzhiyun
134*4882a593Smuzhiyun static struct i2c_driver pca9570_driver = {
135*4882a593Smuzhiyun .driver = {
136*4882a593Smuzhiyun .name = "pca9570",
137*4882a593Smuzhiyun .of_match_table = pca9570_of_match_table,
138*4882a593Smuzhiyun },
139*4882a593Smuzhiyun .probe_new = pca9570_probe,
140*4882a593Smuzhiyun .id_table = pca9570_id_table,
141*4882a593Smuzhiyun };
142*4882a593Smuzhiyun module_i2c_driver(pca9570_driver);
143*4882a593Smuzhiyun
144*4882a593Smuzhiyun MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
145*4882a593Smuzhiyun MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
146*4882a593Smuzhiyun MODULE_LICENSE("GPL v2");
147