GNU Linux-libre 4.9.328-gnu1
[releases.git] / drivers / gpio / gpio-tpic2810.c
1 /*
2  * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
3  *      Andrew F. Davis <afd@ti.com>
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
10  * kind, whether expressed or implied; without even the implied warranty
11  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License version 2 for more details.
13  */
14
15 #include <linux/gpio/driver.h>
16 #include <linux/i2c.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19
20 #define TPIC2810_WS_COMMAND 0x44
21
22 /**
23  * struct tpic2810 - GPIO driver data
24  * @chip: GPIO controller chip
25  * @client: I2C device pointer
26  * @buffer: Buffer for device register
27  * @lock: Protects write sequences
28  */
29 struct tpic2810 {
30         struct gpio_chip chip;
31         struct i2c_client *client;
32         u8 buffer;
33         struct mutex lock;
34 };
35
36 static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value);
37
38 static int tpic2810_get_direction(struct gpio_chip *chip,
39                                   unsigned offset)
40 {
41         /* This device always output */
42         return 0;
43 }
44
45 static int tpic2810_direction_input(struct gpio_chip *chip,
46                                     unsigned offset)
47 {
48         /* This device is output only */
49         return -EINVAL;
50 }
51
52 static int tpic2810_direction_output(struct gpio_chip *chip,
53                                      unsigned offset, int value)
54 {
55         /* This device always output */
56         tpic2810_set(chip, offset, value);
57         return 0;
58 }
59
60 static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits)
61 {
62         struct tpic2810 *gpio = gpiochip_get_data(chip);
63         u8 buffer;
64         int err;
65
66         mutex_lock(&gpio->lock);
67
68         buffer = gpio->buffer & ~mask;
69         buffer |= (mask & bits);
70
71         err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,
72                                         buffer);
73         if (!err)
74                 gpio->buffer = buffer;
75
76         mutex_unlock(&gpio->lock);
77 }
78
79 static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)
80 {
81         tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0);
82 }
83
84 static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,
85                                   unsigned long *bits)
86 {
87         tpic2810_set_mask_bits(chip, *mask, *bits);
88 }
89
90 static const struct gpio_chip template_chip = {
91         .label                  = "tpic2810",
92         .owner                  = THIS_MODULE,
93         .get_direction          = tpic2810_get_direction,
94         .direction_input        = tpic2810_direction_input,
95         .direction_output       = tpic2810_direction_output,
96         .set                    = tpic2810_set,
97         .set_multiple           = tpic2810_set_multiple,
98         .base                   = -1,
99         .ngpio                  = 8,
100         .can_sleep              = true,
101 };
102
103 static const struct of_device_id tpic2810_of_match_table[] = {
104         { .compatible = "ti,tpic2810" },
105         { /* sentinel */ }
106 };
107 MODULE_DEVICE_TABLE(of, tpic2810_of_match_table);
108
109 static int tpic2810_probe(struct i2c_client *client,
110                           const struct i2c_device_id *id)
111 {
112         struct tpic2810 *gpio;
113         int ret;
114
115         gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
116         if (!gpio)
117                 return -ENOMEM;
118
119         i2c_set_clientdata(client, gpio);
120
121         gpio->chip = template_chip;
122         gpio->chip.parent = &client->dev;
123
124         gpio->client = client;
125
126         mutex_init(&gpio->lock);
127
128         ret = gpiochip_add_data(&gpio->chip, gpio);
129         if (ret < 0) {
130                 dev_err(&client->dev, "Unable to register gpiochip\n");
131                 return ret;
132         }
133
134         return 0;
135 }
136
137 static int tpic2810_remove(struct i2c_client *client)
138 {
139         struct tpic2810 *gpio = i2c_get_clientdata(client);
140
141         gpiochip_remove(&gpio->chip);
142
143         return 0;
144 }
145
146 static const struct i2c_device_id tpic2810_id_table[] = {
147         { "tpic2810", },
148         { /* sentinel */ }
149 };
150 MODULE_DEVICE_TABLE(i2c, tpic2810_id_table);
151
152 static struct i2c_driver tpic2810_driver = {
153         .driver = {
154                 .name = "tpic2810",
155                 .of_match_table = tpic2810_of_match_table,
156         },
157         .probe = tpic2810_probe,
158         .remove = tpic2810_remove,
159         .id_table = tpic2810_id_table,
160 };
161 module_i2c_driver(tpic2810_driver);
162
163 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
164 MODULE_DESCRIPTION("TPIC2810 8-Bit LED Driver GPIO Driver");
165 MODULE_LICENSE("GPL v2");