1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * IIO DAC driver for Analog Devices AD8801 DAC 4 * 5 * Copyright (C) 2016 Gwenhael Goavec-Merou 6 */ 7 8 #include <linux/iio/iio.h> 9 #include <linux/module.h> 10 #include <linux/regulator/consumer.h> 11 #include <linux/spi/spi.h> 12 #include <linux/sysfs.h> 13 14 #define AD8801_CFG_ADDR_OFFSET 8 15 16 enum ad8801_device_ids { 17 ID_AD8801, 18 ID_AD8803, 19 }; 20 21 struct ad8801_state { 22 struct spi_device *spi; 23 unsigned char dac_cache[8]; /* Value write on each channel */ 24 unsigned int vrefh_mv; 25 unsigned int vrefl_mv; 26 struct regulator *vrefh_reg; 27 struct regulator *vrefl_reg; 28 29 __be16 data ____cacheline_aligned; 30 }; 31 32 static int ad8801_spi_write(struct ad8801_state *state, 33 u8 channel, unsigned char value) 34 { 35 state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value); 36 return spi_write(state->spi, &state->data, sizeof(state->data)); 37 } 38 39 static int ad8801_write_raw(struct iio_dev *indio_dev, 40 struct iio_chan_spec const *chan, int val, int val2, long mask) 41 { 42 struct ad8801_state *state = iio_priv(indio_dev); 43 int ret; 44 45 switch (mask) { 46 case IIO_CHAN_INFO_RAW: 47 if (val >= 256 || val < 0) 48 return -EINVAL; 49 50 ret = ad8801_spi_write(state, chan->channel, val); 51 if (ret == 0) 52 state->dac_cache[chan->channel] = val; 53 break; 54 default: 55 ret = -EINVAL; 56 } 57 58 return ret; 59 } 60 61 static int ad8801_read_raw(struct iio_dev *indio_dev, 62 struct iio_chan_spec const *chan, int *val, int *val2, long info) 63 { 64 struct ad8801_state *state = iio_priv(indio_dev); 65 66 switch (info) { 67 case IIO_CHAN_INFO_RAW: 68 *val = state->dac_cache[chan->channel]; 69 return IIO_VAL_INT; 70 case IIO_CHAN_INFO_SCALE: 71 *val = state->vrefh_mv - state->vrefl_mv; 72 *val2 = 8; 73 return IIO_VAL_FRACTIONAL_LOG2; 74 case IIO_CHAN_INFO_OFFSET: 75 *val = state->vrefl_mv; 76 return IIO_VAL_INT; 77 default: 78 return -EINVAL; 79 } 80 81 return -EINVAL; 82 } 83 84 static const struct iio_info ad8801_info = { 85 .read_raw = ad8801_read_raw, 86 .write_raw = ad8801_write_raw, 87 }; 88 89 #define AD8801_CHANNEL(chan) { \ 90 .type = IIO_VOLTAGE, \ 91 .indexed = 1, \ 92 .output = 1, \ 93 .channel = chan, \ 94 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 95 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 96 BIT(IIO_CHAN_INFO_OFFSET), \ 97 } 98 99 static const struct iio_chan_spec ad8801_channels[] = { 100 AD8801_CHANNEL(0), 101 AD8801_CHANNEL(1), 102 AD8801_CHANNEL(2), 103 AD8801_CHANNEL(3), 104 AD8801_CHANNEL(4), 105 AD8801_CHANNEL(5), 106 AD8801_CHANNEL(6), 107 AD8801_CHANNEL(7), 108 }; 109 110 static int ad8801_probe(struct spi_device *spi) 111 { 112 struct iio_dev *indio_dev; 113 struct ad8801_state *state; 114 const struct spi_device_id *id; 115 int ret; 116 117 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 118 if (indio_dev == NULL) 119 return -ENOMEM; 120 121 state = iio_priv(indio_dev); 122 state->spi = spi; 123 id = spi_get_device_id(spi); 124 125 state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh"); 126 if (IS_ERR(state->vrefh_reg)) { 127 dev_err(&spi->dev, "Vrefh regulator not specified\n"); 128 return PTR_ERR(state->vrefh_reg); 129 } 130 131 ret = regulator_enable(state->vrefh_reg); 132 if (ret) { 133 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n", 134 ret); 135 return ret; 136 } 137 138 ret = regulator_get_voltage(state->vrefh_reg); 139 if (ret < 0) { 140 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n", 141 ret); 142 goto error_disable_vrefh_reg; 143 } 144 state->vrefh_mv = ret / 1000; 145 146 if (id->driver_data == ID_AD8803) { 147 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl"); 148 if (IS_ERR(state->vrefl_reg)) { 149 dev_err(&spi->dev, "Vrefl regulator not specified\n"); 150 ret = PTR_ERR(state->vrefl_reg); 151 goto error_disable_vrefh_reg; 152 } 153 154 ret = regulator_enable(state->vrefl_reg); 155 if (ret) { 156 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n", 157 ret); 158 goto error_disable_vrefh_reg; 159 } 160 161 ret = regulator_get_voltage(state->vrefl_reg); 162 if (ret < 0) { 163 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n", 164 ret); 165 goto error_disable_vrefl_reg; 166 } 167 state->vrefl_mv = ret / 1000; 168 } else { 169 state->vrefl_mv = 0; 170 state->vrefl_reg = NULL; 171 } 172 173 spi_set_drvdata(spi, indio_dev); 174 indio_dev->dev.parent = &spi->dev; 175 indio_dev->info = &ad8801_info; 176 indio_dev->modes = INDIO_DIRECT_MODE; 177 indio_dev->channels = ad8801_channels; 178 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels); 179 indio_dev->name = id->name; 180 181 ret = iio_device_register(indio_dev); 182 if (ret) { 183 dev_err(&spi->dev, "Failed to register iio device: %d\n", 184 ret); 185 goto error_disable_vrefl_reg; 186 } 187 188 return 0; 189 190 error_disable_vrefl_reg: 191 if (state->vrefl_reg) 192 regulator_disable(state->vrefl_reg); 193 error_disable_vrefh_reg: 194 regulator_disable(state->vrefh_reg); 195 return ret; 196 } 197 198 static int ad8801_remove(struct spi_device *spi) 199 { 200 struct iio_dev *indio_dev = spi_get_drvdata(spi); 201 struct ad8801_state *state = iio_priv(indio_dev); 202 203 iio_device_unregister(indio_dev); 204 if (state->vrefl_reg) 205 regulator_disable(state->vrefl_reg); 206 regulator_disable(state->vrefh_reg); 207 208 return 0; 209 } 210 211 static const struct spi_device_id ad8801_ids[] = { 212 {"ad8801", ID_AD8801}, 213 {"ad8803", ID_AD8803}, 214 {} 215 }; 216 MODULE_DEVICE_TABLE(spi, ad8801_ids); 217 218 static struct spi_driver ad8801_driver = { 219 .driver = { 220 .name = "ad8801", 221 }, 222 .probe = ad8801_probe, 223 .remove = ad8801_remove, 224 .id_table = ad8801_ids, 225 }; 226 module_spi_driver(ad8801_driver); 227 228 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>"); 229 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC"); 230 MODULE_LICENSE("GPL v2"); 231