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