xref: /openbmc/linux/drivers/base/regmap/regmap-i2c.c (revision 31b90347)
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 
18 static 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 
33 static 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 
67 static 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 
95 static 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  */
110 struct 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 }
115 EXPORT_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  */
127 struct 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 }
132 EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);
133 
134 MODULE_LICENSE("GPL");
135