Mark Brown | 9943fa3 | 2011-06-20 19:02:29 +0100 | [diff] [blame^] | 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(struct device *dev, const void *data, size_t count) |
| 19 | { |
| 20 | struct i2c_client *i2c = to_i2c_client(dev); |
| 21 | int ret; |
| 22 | |
| 23 | ret = i2c_master_send(i2c, data, count); |
| 24 | if (ret == count) |
| 25 | return 0; |
| 26 | else if (ret < 0) |
| 27 | return ret; |
| 28 | else |
| 29 | return -EIO; |
| 30 | } |
| 31 | |
| 32 | static int regmap_i2c_gather_write(struct device *dev, |
| 33 | const void *reg, size_t reg_size, |
| 34 | const void *val, size_t val_size) |
| 35 | { |
| 36 | struct i2c_client *i2c = to_i2c_client(dev); |
| 37 | struct i2c_msg xfer[2]; |
| 38 | int ret; |
| 39 | |
| 40 | /* If the I2C controller can't do a gather tell the core, it |
| 41 | * will substitute in a linear write for us. |
| 42 | */ |
| 43 | if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING)) |
| 44 | return -ENOTSUPP; |
| 45 | |
| 46 | xfer[0].addr = i2c->addr; |
| 47 | xfer[0].flags = 0; |
| 48 | xfer[0].len = reg_size; |
| 49 | xfer[0].buf = (void *)reg; |
| 50 | |
| 51 | xfer[1].addr = i2c->addr; |
| 52 | xfer[1].flags = I2C_M_NOSTART; |
| 53 | xfer[1].len = val_size; |
| 54 | xfer[1].buf = (void *)val; |
| 55 | |
| 56 | ret = i2c_transfer(i2c->adapter, xfer, 2); |
| 57 | if (ret == 2) |
| 58 | return 0; |
| 59 | if (ret < 0) |
| 60 | return ret; |
| 61 | else |
| 62 | return -EIO; |
| 63 | } |
| 64 | |
| 65 | static int regmap_i2c_read(struct device *dev, |
| 66 | const void *reg, size_t reg_size, |
| 67 | void *val, size_t val_size) |
| 68 | { |
| 69 | struct i2c_client *i2c = to_i2c_client(dev); |
| 70 | struct i2c_msg xfer[2]; |
| 71 | int ret; |
| 72 | |
| 73 | xfer[0].addr = i2c->addr; |
| 74 | xfer[0].flags = 0; |
| 75 | xfer[0].len = reg_size; |
| 76 | xfer[0].buf = (void *)reg; |
| 77 | |
| 78 | xfer[1].addr = i2c->addr; |
| 79 | xfer[1].flags = I2C_M_RD; |
| 80 | xfer[1].len = val_size; |
| 81 | xfer[1].buf = val; |
| 82 | |
| 83 | ret = i2c_transfer(i2c->adapter, xfer, 2); |
| 84 | if (ret == 2) |
| 85 | return 0; |
| 86 | else if (ret < 0) |
| 87 | return ret; |
| 88 | else |
| 89 | return -EIO; |
| 90 | } |
| 91 | |
| 92 | static struct regmap_bus regmap_i2c = { |
| 93 | .type = &i2c_bus_type, |
| 94 | .write = regmap_i2c_write, |
| 95 | .gather_write = regmap_i2c_gather_write, |
| 96 | .read = regmap_i2c_read, |
| 97 | .owner = THIS_MODULE, |
| 98 | }; |
| 99 | |
| 100 | /** |
| 101 | * regmap_init_i2c(): Initialise register map |
| 102 | * |
| 103 | * @i2c: Device that will be interacted with |
| 104 | * @config: Configuration for register map |
| 105 | * |
| 106 | * The return value will be an ERR_PTR() on error or a valid pointer to |
| 107 | * a struct regmap. |
| 108 | */ |
| 109 | struct regmap *regmap_init_i2c(struct i2c_client *i2c, |
| 110 | const struct regmap_config *config) |
| 111 | { |
| 112 | return regmap_init(&i2c->dev, ®map_i2c, config); |
| 113 | } |
| 114 | EXPORT_SYMBOL_GPL(regmap_init_i2c); |
| 115 | |