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"); 232