1 /* 2 * Industrial I/O driver for Microchip digital potentiometers 3 * Copyright (c) 2015 Axentia Technologies AB 4 * Author: Peter Rosin <peda@axentia.se> 5 * 6 * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf 7 * 8 * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address 9 * mcp4531 1 129 5, 10, 50, 100 010111x 10 * mcp4532 1 129 5, 10, 50, 100 01011xx 11 * mcp4551 1 257 5, 10, 50, 100 010111x 12 * mcp4552 1 257 5, 10, 50, 100 01011xx 13 * mcp4631 2 129 5, 10, 50, 100 0101xxx 14 * mcp4632 2 129 5, 10, 50, 100 01011xx 15 * mcp4651 2 257 5, 10, 50, 100 0101xxx 16 * mcp4652 2 257 5, 10, 50, 100 01011xx 17 * 18 * This program is free software; you can redistribute it and/or modify it 19 * under the terms of the GNU General Public License version 2 as published by 20 * the Free Software Foundation. 21 */ 22 23 #include <linux/module.h> 24 #include <linux/i2c.h> 25 #include <linux/err.h> 26 27 #include <linux/iio/iio.h> 28 29 struct mcp4531_cfg { 30 int wipers; 31 int max_pos; 32 int kohms; 33 }; 34 35 enum mcp4531_type { 36 MCP453x_502, 37 MCP453x_103, 38 MCP453x_503, 39 MCP453x_104, 40 MCP455x_502, 41 MCP455x_103, 42 MCP455x_503, 43 MCP455x_104, 44 MCP463x_502, 45 MCP463x_103, 46 MCP463x_503, 47 MCP463x_104, 48 MCP465x_502, 49 MCP465x_103, 50 MCP465x_503, 51 MCP465x_104, 52 }; 53 54 static const struct mcp4531_cfg mcp4531_cfg[] = { 55 [MCP453x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, }, 56 [MCP453x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, 57 [MCP453x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, }, 58 [MCP453x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, }, 59 [MCP455x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, }, 60 [MCP455x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, }, 61 [MCP455x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, 62 [MCP455x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, 63 [MCP463x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, }, 64 [MCP463x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, }, 65 [MCP463x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, }, 66 [MCP463x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, }, 67 [MCP465x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, }, 68 [MCP465x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, }, 69 [MCP465x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, }, 70 [MCP465x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, }, 71 }; 72 73 #define MCP4531_WRITE (0 << 2) 74 #define MCP4531_INCR (1 << 2) 75 #define MCP4531_DECR (2 << 2) 76 #define MCP4531_READ (3 << 2) 77 78 #define MCP4531_WIPER_SHIFT (4) 79 80 struct mcp4531_data { 81 struct i2c_client *client; 82 const struct mcp4531_cfg *cfg; 83 }; 84 85 #define MCP4531_CHANNEL(ch) { \ 86 .type = IIO_RESISTANCE, \ 87 .indexed = 1, \ 88 .output = 1, \ 89 .channel = (ch), \ 90 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 91 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 92 } 93 94 static const struct iio_chan_spec mcp4531_channels[] = { 95 MCP4531_CHANNEL(0), 96 MCP4531_CHANNEL(1), 97 }; 98 99 static int mcp4531_read_raw(struct iio_dev *indio_dev, 100 struct iio_chan_spec const *chan, 101 int *val, int *val2, long mask) 102 { 103 struct mcp4531_data *data = iio_priv(indio_dev); 104 int address = chan->channel << MCP4531_WIPER_SHIFT; 105 s32 ret; 106 107 switch (mask) { 108 case IIO_CHAN_INFO_RAW: 109 ret = i2c_smbus_read_word_swapped(data->client, 110 MCP4531_READ | address); 111 if (ret < 0) 112 return ret; 113 *val = ret; 114 return IIO_VAL_INT; 115 case IIO_CHAN_INFO_SCALE: 116 *val = 1000 * data->cfg->kohms; 117 *val2 = data->cfg->max_pos; 118 return IIO_VAL_FRACTIONAL; 119 } 120 121 return -EINVAL; 122 } 123 124 static int mcp4531_write_raw(struct iio_dev *indio_dev, 125 struct iio_chan_spec const *chan, 126 int val, int val2, long mask) 127 { 128 struct mcp4531_data *data = iio_priv(indio_dev); 129 int address = chan->channel << MCP4531_WIPER_SHIFT; 130 131 switch (mask) { 132 case IIO_CHAN_INFO_RAW: 133 if (val > data->cfg->max_pos || val < 0) 134 return -EINVAL; 135 break; 136 default: 137 return -EINVAL; 138 } 139 140 return i2c_smbus_write_byte_data(data->client, 141 MCP4531_WRITE | address | (val >> 8), 142 val & 0xff); 143 } 144 145 static const struct iio_info mcp4531_info = { 146 .read_raw = mcp4531_read_raw, 147 .write_raw = mcp4531_write_raw, 148 .driver_module = THIS_MODULE, 149 }; 150 151 static int mcp4531_probe(struct i2c_client *client, 152 const struct i2c_device_id *id) 153 { 154 struct device *dev = &client->dev; 155 struct mcp4531_data *data; 156 struct iio_dev *indio_dev; 157 158 if (!i2c_check_functionality(client->adapter, 159 I2C_FUNC_SMBUS_WORD_DATA)) { 160 dev_err(dev, "SMBUS Word Data not supported\n"); 161 return -EOPNOTSUPP; 162 } 163 164 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 165 if (!indio_dev) 166 return -ENOMEM; 167 data = iio_priv(indio_dev); 168 i2c_set_clientdata(client, indio_dev); 169 data->client = client; 170 data->cfg = &mcp4531_cfg[id->driver_data]; 171 172 indio_dev->dev.parent = dev; 173 indio_dev->info = &mcp4531_info; 174 indio_dev->channels = mcp4531_channels; 175 indio_dev->num_channels = data->cfg->wipers; 176 indio_dev->name = client->name; 177 178 return devm_iio_device_register(dev, indio_dev); 179 } 180 181 static const struct i2c_device_id mcp4531_id[] = { 182 { "mcp4531-502", MCP453x_502 }, 183 { "mcp4531-103", MCP453x_103 }, 184 { "mcp4531-503", MCP453x_503 }, 185 { "mcp4531-104", MCP453x_104 }, 186 { "mcp4532-502", MCP453x_502 }, 187 { "mcp4532-103", MCP453x_103 }, 188 { "mcp4532-503", MCP453x_503 }, 189 { "mcp4532-104", MCP453x_104 }, 190 { "mcp4551-502", MCP455x_502 }, 191 { "mcp4551-103", MCP455x_103 }, 192 { "mcp4551-503", MCP455x_503 }, 193 { "mcp4551-104", MCP455x_104 }, 194 { "mcp4552-502", MCP455x_502 }, 195 { "mcp4552-103", MCP455x_103 }, 196 { "mcp4552-503", MCP455x_503 }, 197 { "mcp4552-104", MCP455x_104 }, 198 { "mcp4631-502", MCP463x_502 }, 199 { "mcp4631-103", MCP463x_103 }, 200 { "mcp4631-503", MCP463x_503 }, 201 { "mcp4631-104", MCP463x_104 }, 202 { "mcp4632-502", MCP463x_502 }, 203 { "mcp4632-103", MCP463x_103 }, 204 { "mcp4632-503", MCP463x_503 }, 205 { "mcp4632-104", MCP463x_104 }, 206 { "mcp4651-502", MCP465x_502 }, 207 { "mcp4651-103", MCP465x_103 }, 208 { "mcp4651-503", MCP465x_503 }, 209 { "mcp4651-104", MCP465x_104 }, 210 { "mcp4652-502", MCP465x_502 }, 211 { "mcp4652-103", MCP465x_103 }, 212 { "mcp4652-503", MCP465x_503 }, 213 { "mcp4652-104", MCP465x_104 }, 214 {} 215 }; 216 MODULE_DEVICE_TABLE(i2c, mcp4531_id); 217 218 static struct i2c_driver mcp4531_driver = { 219 .driver = { 220 .name = "mcp4531", 221 }, 222 .probe = mcp4531_probe, 223 .id_table = mcp4531_id, 224 }; 225 226 module_i2c_driver(mcp4531_driver); 227 228 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); 229 MODULE_DESCRIPTION("MCP4531 digital potentiometer"); 230 MODULE_LICENSE("GPL"); 231