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16d44b60 SE |
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 | /** | |
19 | * struct pca9570 - GPIO driver data | |
20 | * @chip: GPIO controller chip | |
21 | * @lock: Protects write sequences | |
22 | * @out: Buffer for device register | |
23 | */ | |
24 | struct pca9570 { | |
25 | struct gpio_chip chip; | |
26 | struct mutex lock; | |
27 | u8 out; | |
28 | }; | |
29 | ||
30 | static int pca9570_read(struct pca9570 *gpio, u8 *value) | |
31 | { | |
32 | struct i2c_client *client = to_i2c_client(gpio->chip.parent); | |
33 | int ret; | |
34 | ||
35 | ret = i2c_smbus_read_byte(client); | |
36 | if (ret < 0) | |
37 | return ret; | |
38 | ||
39 | *value = ret; | |
40 | return 0; | |
41 | } | |
42 | ||
43 | static int pca9570_write(struct pca9570 *gpio, u8 value) | |
44 | { | |
45 | struct i2c_client *client = to_i2c_client(gpio->chip.parent); | |
46 | ||
47 | return i2c_smbus_write_byte(client, value); | |
48 | } | |
49 | ||
50 | static int pca9570_get_direction(struct gpio_chip *chip, | |
51 | unsigned offset) | |
52 | { | |
53 | /* This device always output */ | |
54 | return GPIO_LINE_DIRECTION_OUT; | |
55 | } | |
56 | ||
57 | static int pca9570_get(struct gpio_chip *chip, unsigned offset) | |
58 | { | |
59 | struct pca9570 *gpio = gpiochip_get_data(chip); | |
60 | u8 buffer; | |
61 | int ret; | |
62 | ||
63 | ret = pca9570_read(gpio, &buffer); | |
64 | if (ret) | |
65 | return ret; | |
66 | ||
67 | return !!(buffer & BIT(offset)); | |
68 | } | |
69 | ||
70 | static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value) | |
71 | { | |
72 | struct pca9570 *gpio = gpiochip_get_data(chip); | |
73 | u8 buffer; | |
74 | int ret; | |
75 | ||
76 | mutex_lock(&gpio->lock); | |
77 | ||
78 | buffer = gpio->out; | |
79 | if (value) | |
80 | buffer |= BIT(offset); | |
81 | else | |
82 | buffer &= ~BIT(offset); | |
83 | ||
84 | ret = pca9570_write(gpio, buffer); | |
85 | if (ret) | |
86 | goto out; | |
87 | ||
88 | gpio->out = buffer; | |
89 | ||
90 | out: | |
91 | mutex_unlock(&gpio->lock); | |
92 | } | |
93 | ||
94 | static int pca9570_probe(struct i2c_client *client) | |
95 | { | |
96 | struct pca9570 *gpio; | |
97 | ||
98 | gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL); | |
99 | if (!gpio) | |
100 | return -ENOMEM; | |
101 | ||
102 | gpio->chip.label = client->name; | |
103 | gpio->chip.parent = &client->dev; | |
104 | gpio->chip.owner = THIS_MODULE; | |
105 | gpio->chip.get_direction = pca9570_get_direction; | |
106 | gpio->chip.get = pca9570_get; | |
107 | gpio->chip.set = pca9570_set; | |
108 | gpio->chip.base = -1; | |
109 | gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev); | |
110 | gpio->chip.can_sleep = true; | |
111 | ||
112 | mutex_init(&gpio->lock); | |
113 | ||
114 | /* Read the current output level */ | |
115 | pca9570_read(gpio, &gpio->out); | |
116 | ||
117 | i2c_set_clientdata(client, gpio); | |
118 | ||
119 | return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio); | |
120 | } | |
121 | ||
122 | static const struct i2c_device_id pca9570_id_table[] = { | |
123 | { "pca9570", 4 }, | |
124 | { /* sentinel */ } | |
125 | }; | |
126 | MODULE_DEVICE_TABLE(i2c, pca9570_id_table); | |
127 | ||
128 | static const struct of_device_id pca9570_of_match_table[] = { | |
129 | { .compatible = "nxp,pca9570", .data = (void *)4 }, | |
130 | { /* sentinel */ } | |
131 | }; | |
132 | MODULE_DEVICE_TABLE(of, pca9570_of_match_table); | |
133 | ||
134 | static struct i2c_driver pca9570_driver = { | |
135 | .driver = { | |
136 | .name = "pca9570", | |
137 | .of_match_table = pca9570_of_match_table, | |
138 | }, | |
139 | .probe_new = pca9570_probe, | |
140 | .id_table = pca9570_id_table, | |
141 | }; | |
142 | module_i2c_driver(pca9570_driver); | |
143 | ||
144 | MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>"); | |
145 | MODULE_DESCRIPTION("GPIO expander driver for PCA9570"); | |
146 | MODULE_LICENSE("GPL v2"); |