drivers/iio/potentiometer/ad5272.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Analog Devices AD5272 digital potentiometer driver
   4  * Copyright (C) 2018 Phil Reid <preid@electromag.com.au>
   5  *
   6  * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf
   7  *
   8  * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
   9  * ad5272       1       1024            20, 50, 100             01011xx
  10  * ad5274       1       256             20, 100                 01011xx
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/i2c.h>
  16 #include <linux/iio/iio.h>
  17 #include <linux/module.h>
  18
  19 #define  AD5272_RDAC_WR  1
  20 #define  AD5272_RDAC_RD  2
  21 #define  AD5272_RESET    4
  22 #define  AD5272_CTL      7
  23
  24 #define  AD5272_RDAC_WR_EN  BIT(1)
  25
  26 struct ad5272_cfg {
  27         int max_pos;
  28         int kohms;
  29         int shift;
  30 };
  31
  32 enum ad5272_type {
  33         AD5272_020,
  34         AD5272_050,
  35         AD5272_100,
  36         AD5274_020,
  37         AD5274_100,
  38 };
  39
  40 static const struct ad5272_cfg ad5272_cfg[] = {
  41         [AD5272_020] = { .max_pos = 1024, .kohms = 20 },
  42         [AD5272_050] = { .max_pos = 1024, .kohms = 50 },
  43         [AD5272_100] = { .max_pos = 1024, .kohms = 100 },
  44         [AD5274_020] = { .max_pos = 256,  .kohms = 20,  .shift = 2 },
  45         [AD5274_100] = { .max_pos = 256,  .kohms = 100, .shift = 2 },
  46 };
  47
  48 struct ad5272_data {
  49         struct i2c_client       *client;
  50         struct mutex            lock;
  51         const struct ad5272_cfg *cfg;
  52         u8                      buf[2] ____cacheline_aligned;
  53 };
  54
  55 static const struct iio_chan_spec ad5272_channel = {
  56         .type = IIO_RESISTANCE,
  57         .output = 1,
  58         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  59         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
  60 };
  61
  62 static int ad5272_write(struct ad5272_data *data, int reg, int val)
  63 {
  64         int ret;
  65
  66         data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
  67         data->buf[1] = (u8)val;
  68
  69         mutex_lock(&data->lock);
  70         ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
  71         mutex_unlock(&data->lock);
  72         return ret < 0 ? ret : 0;
  73 }
  74
  75 static int ad5272_read(struct ad5272_data *data, int reg, int *val)
  76 {
  77         int ret;
  78
  79         data->buf[0] = reg << 2;
  80         data->buf[1] = 0;
  81
  82         mutex_lock(&data->lock);
  83         ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
  84         if (ret < 0)
  85                 goto error;
  86
  87         ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
  88         if (ret < 0)
  89                 goto error;
  90
  91         *val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
  92         ret = 0;
  93 error:
  94         mutex_unlock(&data->lock);
  95         return ret;
  96 }
  97
  98 static int ad5272_read_raw(struct iio_dev *indio_dev,
  99                            struct iio_chan_spec const *chan,
 100                            int *val, int *val2, long mask)
 101 {
 102         struct ad5272_data *data = iio_priv(indio_dev);
 103         int ret;
 104
 105         switch (mask) {
 106         case IIO_CHAN_INFO_RAW: {
 107                 ret = ad5272_read(data, AD5272_RDAC_RD, val);
 108                 *val = *val >> data->cfg->shift;
 109                 return ret ? ret : IIO_VAL_INT;
 110         }
 111         case IIO_CHAN_INFO_SCALE:
 112                 *val = 1000 * data->cfg->kohms;
 113                 *val2 = data->cfg->max_pos;
 114                 return IIO_VAL_FRACTIONAL;
 115         }
 116
 117         return -EINVAL;
 118 }
 119
 120 static int ad5272_write_raw(struct iio_dev *indio_dev,
 121                             struct iio_chan_spec const *chan,
 122                             int val, int val2, long mask)
 123 {
 124         struct ad5272_data *data = iio_priv(indio_dev);
 125
 126         if (mask != IIO_CHAN_INFO_RAW)
 127                 return -EINVAL;
 128
 129         if (val >= data->cfg->max_pos || val < 0 || val2)
 130                 return -EINVAL;
 131
 132         return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
 133 }
 134
 135 static const struct iio_info ad5272_info = {
 136         .read_raw = ad5272_read_raw,
 137         .write_raw = ad5272_write_raw,
 138 };
 139
 140 static int ad5272_reset(struct ad5272_data *data)
 141 {
 142         struct gpio_desc *reset_gpio;
 143
 144         reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
 145                 GPIOD_OUT_LOW);
 146         if (IS_ERR(reset_gpio))
 147                 return PTR_ERR(reset_gpio);
 148
 149         if (reset_gpio) {
 150                 udelay(1);
 151                 gpiod_set_value(reset_gpio, 1);
 152         } else {
 153                 ad5272_write(data, AD5272_RESET, 0);
 154         }
 155         usleep_range(1000, 2000);
 156
 157         return 0;
 158 }
 159
 160 static int ad5272_probe(struct i2c_client *client,
 161                         const struct i2c_device_id *id)
 162 {
 163         struct device *dev = &client->dev;
 164         struct iio_dev *indio_dev;
 165         struct ad5272_data *data;
 166         int ret;
 167
 168         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 169         if (!indio_dev)
 170                 return -ENOMEM;
 171
 172         i2c_set_clientdata(client, indio_dev);
 173
 174         data = iio_priv(indio_dev);
 175         data->client = client;
 176         mutex_init(&data->lock);
 177         data->cfg = &ad5272_cfg[id->driver_data];
 178
 179         ret = ad5272_reset(data);
 180         if (ret)
 181                 return ret;
 182
 183         ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
 184         if (ret < 0)
 185                 return -ENODEV;
 186
 187         indio_dev->dev.parent = dev;
 188         indio_dev->info = &ad5272_info;
 189         indio_dev->channels = &ad5272_channel;
 190         indio_dev->num_channels = 1;
 191         indio_dev->name = client->name;
 192
 193         return devm_iio_device_register(dev, indio_dev);
 194 }
 195
 196 #if defined(CONFIG_OF)
 197 static const struct of_device_id ad5272_dt_ids[] = {
 198         { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
 199         { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
 200         { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
 201         { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
 202         { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
 203         {}
 204 };
 205 MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
 206 #endif /* CONFIG_OF */
 207
 208 static const struct i2c_device_id ad5272_id[] = {
 209         { "ad5272-020", AD5272_020 },
 210         { "ad5272-050", AD5272_050 },
 211         { "ad5272-100", AD5272_100 },
 212         { "ad5274-020", AD5274_020 },
 213         { "ad5274-100", AD5274_100 },
 214         {}
 215 };
 216 MODULE_DEVICE_TABLE(i2c, ad5272_id);
 217
 218 static struct i2c_driver ad5272_driver = {
 219         .driver = {
 220                 .name   = "ad5272",
 221                 .of_match_table = of_match_ptr(ad5272_dt_ids),
 222         },
 223         .probe          = ad5272_probe,
 224         .id_table       = ad5272_id,
 225 };
 226
 227 module_i2c_driver(ad5272_driver);
 228
 229 MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
 230 MODULE_DESCRIPTION("AD5272 digital potentiometer");
 231 MODULE_LICENSE("GPL v2");