1 /* 2 * tpl0102.c - Support for Texas Instruments digital potentiometers 3 * 4 * Copyright (C) 2016 Matt Ranostay <mranostay@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * TODO: enable/disable hi-z output control 17 */ 18 19 #include <linux/module.h> 20 #include <linux/i2c.h> 21 #include <linux/regmap.h> 22 #include <linux/iio/iio.h> 23 24 struct tpl0102_cfg { 25 int wipers; 26 int max_pos; 27 int kohms; 28 }; 29 30 enum tpl0102_type { 31 CAT5140_503, 32 CAT5140_104, 33 TPL0102_104, 34 TPL0401_103, 35 }; 36 37 static const struct tpl0102_cfg tpl0102_cfg[] = { 38 /* on-semiconductor parts */ 39 [CAT5140_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, 40 [CAT5140_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, 41 /* ti parts */ 42 [TPL0102_104] = { .wipers = 2, .max_pos = 256, .kohms = 100 }, 43 [TPL0401_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, 44 }; 45 46 struct tpl0102_data { 47 struct regmap *regmap; 48 unsigned long devid; 49 }; 50 51 static const struct regmap_config tpl0102_regmap_config = { 52 .reg_bits = 8, 53 .val_bits = 8, 54 }; 55 56 #define TPL0102_CHANNEL(ch) { \ 57 .type = IIO_RESISTANCE, \ 58 .indexed = 1, \ 59 .output = 1, \ 60 .channel = (ch), \ 61 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 62 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 63 } 64 65 static const struct iio_chan_spec tpl0102_channels[] = { 66 TPL0102_CHANNEL(0), 67 TPL0102_CHANNEL(1), 68 }; 69 70 static int tpl0102_read_raw(struct iio_dev *indio_dev, 71 struct iio_chan_spec const *chan, 72 int *val, int *val2, long mask) 73 { 74 struct tpl0102_data *data = iio_priv(indio_dev); 75 76 switch (mask) { 77 case IIO_CHAN_INFO_RAW: { 78 int ret = regmap_read(data->regmap, chan->channel, val); 79 80 return ret ? ret : IIO_VAL_INT; 81 } 82 case IIO_CHAN_INFO_SCALE: 83 *val = 1000 * tpl0102_cfg[data->devid].kohms; 84 *val2 = tpl0102_cfg[data->devid].max_pos; 85 return IIO_VAL_FRACTIONAL; 86 } 87 88 return -EINVAL; 89 } 90 91 static int tpl0102_write_raw(struct iio_dev *indio_dev, 92 struct iio_chan_spec const *chan, 93 int val, int val2, long mask) 94 { 95 struct tpl0102_data *data = iio_priv(indio_dev); 96 97 if (mask != IIO_CHAN_INFO_RAW) 98 return -EINVAL; 99 100 if (val >= tpl0102_cfg[data->devid].max_pos || val < 0) 101 return -EINVAL; 102 103 return regmap_write(data->regmap, chan->channel, val); 104 } 105 106 static const struct iio_info tpl0102_info = { 107 .read_raw = tpl0102_read_raw, 108 .write_raw = tpl0102_write_raw, 109 .driver_module = THIS_MODULE, 110 }; 111 112 static int tpl0102_probe(struct i2c_client *client, 113 const struct i2c_device_id *id) 114 { 115 struct device *dev = &client->dev; 116 struct tpl0102_data *data; 117 struct iio_dev *indio_dev; 118 119 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 120 if (!indio_dev) 121 return -ENOMEM; 122 data = iio_priv(indio_dev); 123 i2c_set_clientdata(client, indio_dev); 124 125 data->devid = id->driver_data; 126 data->regmap = devm_regmap_init_i2c(client, &tpl0102_regmap_config); 127 if (IS_ERR(data->regmap)) { 128 dev_err(dev, "regmap initialization failed\n"); 129 return PTR_ERR(data->regmap); 130 } 131 132 indio_dev->dev.parent = dev; 133 indio_dev->info = &tpl0102_info; 134 indio_dev->channels = tpl0102_channels; 135 indio_dev->num_channels = tpl0102_cfg[data->devid].wipers; 136 indio_dev->name = client->name; 137 138 return devm_iio_device_register(dev, indio_dev); 139 } 140 141 static const struct i2c_device_id tpl0102_id[] = { 142 { "cat5140-503", CAT5140_503 }, 143 { "cat5140-104", CAT5140_104 }, 144 { "tpl0102-104", TPL0102_104 }, 145 { "tpl0401-103", TPL0401_103 }, 146 {} 147 }; 148 MODULE_DEVICE_TABLE(i2c, tpl0102_id); 149 150 static struct i2c_driver tpl0102_driver = { 151 .driver = { 152 .name = "tpl0102", 153 }, 154 .probe = tpl0102_probe, 155 .id_table = tpl0102_id, 156 }; 157 158 module_i2c_driver(tpl0102_driver); 159 160 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); 161 MODULE_DESCRIPTION("TPL0102 digital potentiometer"); 162 MODULE_LICENSE("GPL"); 163