Root/drivers/base/regmap/regmap-i2c.c

1/*
2 * Register map access API - I2C support
3 *
4 * Copyright 2011 Wolfson Microelectronics plc
5 *
6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/regmap.h>
14#include <linux/i2c.h>
15#include <linux/module.h>
16#include <linux/init.h>
17
18static int regmap_i2c_write(void *context, const void *data, size_t count)
19{
20    struct device *dev = context;
21    struct i2c_client *i2c = to_i2c_client(dev);
22    int ret;
23
24    ret = i2c_master_send(i2c, data, count);
25    if (ret == count)
26        return 0;
27    else if (ret < 0)
28        return ret;
29    else
30        return -EIO;
31}
32
33static int regmap_i2c_gather_write(void *context,
34                   const void *reg, size_t reg_size,
35                   const void *val, size_t val_size)
36{
37    struct device *dev = context;
38    struct i2c_client *i2c = to_i2c_client(dev);
39    struct i2c_msg xfer[2];
40    int ret;
41
42    /* If the I2C controller can't do a gather tell the core, it
43     * will substitute in a linear write for us.
44     */
45    if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
46        return -ENOTSUPP;
47
48    xfer[0].addr = i2c->addr;
49    xfer[0].flags = 0;
50    xfer[0].len = reg_size;
51    xfer[0].buf = (void *)reg;
52
53    xfer[1].addr = i2c->addr;
54    xfer[1].flags = I2C_M_NOSTART;
55    xfer[1].len = val_size;
56    xfer[1].buf = (void *)val;
57
58    ret = i2c_transfer(i2c->adapter, xfer, 2);
59    if (ret == 2)
60        return 0;
61    if (ret < 0)
62        return ret;
63    else
64        return -EIO;
65}
66
67static int regmap_i2c_read(void *context,
68               const void *reg, size_t reg_size,
69               void *val, size_t val_size)
70{
71    struct device *dev = context;
72    struct i2c_client *i2c = to_i2c_client(dev);
73    struct i2c_msg xfer[2];
74    int ret;
75
76    xfer[0].addr = i2c->addr;
77    xfer[0].flags = 0;
78    xfer[0].len = reg_size;
79    xfer[0].buf = (void *)reg;
80
81    xfer[1].addr = i2c->addr;
82    xfer[1].flags = I2C_M_RD;
83    xfer[1].len = val_size;
84    xfer[1].buf = val;
85
86    ret = i2c_transfer(i2c->adapter, xfer, 2);
87    if (ret == 2)
88        return 0;
89    else if (ret < 0)
90        return ret;
91    else
92        return -EIO;
93}
94
95static struct regmap_bus regmap_i2c = {
96    .write = regmap_i2c_write,
97    .gather_write = regmap_i2c_gather_write,
98    .read = regmap_i2c_read,
99};
100
101/**
102 * regmap_init_i2c(): Initialise register map
103 *
104 * @i2c: Device that will be interacted with
105 * @config: Configuration for register map
106 *
107 * The return value will be an ERR_PTR() on error or a valid pointer to
108 * a struct regmap.
109 */
110struct regmap *regmap_init_i2c(struct i2c_client *i2c,
111                   const struct regmap_config *config)
112{
113    return regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
114}
115EXPORT_SYMBOL_GPL(regmap_init_i2c);
116
117/**
118 * devm_regmap_init_i2c(): Initialise managed register map
119 *
120 * @i2c: Device that will be interacted with
121 * @config: Configuration for register map
122 *
123 * The return value will be an ERR_PTR() on error or a valid pointer
124 * to a struct regmap. The regmap will be automatically freed by the
125 * device management code.
126 */
127struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
128                    const struct regmap_config *config)
129{
130    return devm_regmap_init(&i2c->dev, &regmap_i2c, &i2c->dev, config);
131}
132EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
133
134MODULE_LICENSE("GPL");
135

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