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 __aligned(IIO_DMA_MINALIGN); 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 return dev_err_probe(&spi->dev, PTR_ERR(state->vrefh_reg), 128 "Vrefh regulator not specified\n"); 129 130 ret = regulator_enable(state->vrefh_reg); 131 if (ret) { 132 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n", 133 ret); 134 return ret; 135 } 136 137 ret = regulator_get_voltage(state->vrefh_reg); 138 if (ret < 0) { 139 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n", 140 ret); 141 goto error_disable_vrefh_reg; 142 } 143 state->vrefh_mv = ret / 1000; 144 145 if (id->driver_data == ID_AD8803) { 146 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl"); 147 if (IS_ERR(state->vrefl_reg)) { 148 ret = dev_err_probe(&spi->dev, PTR_ERR(state->vrefl_reg), 149 "Vrefl regulator not specified\n"); 150 goto error_disable_vrefh_reg; 151 } 152 153 ret = regulator_enable(state->vrefl_reg); 154 if (ret) { 155 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n", 156 ret); 157 goto error_disable_vrefh_reg; 158 } 159 160 ret = regulator_get_voltage(state->vrefl_reg); 161 if (ret < 0) { 162 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n", 163 ret); 164 goto error_disable_vrefl_reg; 165 } 166 state->vrefl_mv = ret / 1000; 167 } else { 168 state->vrefl_mv = 0; 169 state->vrefl_reg = NULL; 170 } 171 172 spi_set_drvdata(spi, indio_dev); 173 indio_dev->info = &ad8801_info; 174 indio_dev->modes = INDIO_DIRECT_MODE; 175 indio_dev->channels = ad8801_channels; 176 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels); 177 indio_dev->name = id->name; 178 179 ret = iio_device_register(indio_dev); 180 if (ret) { 181 dev_err(&spi->dev, "Failed to register iio device: %d\n", 182 ret); 183 goto error_disable_vrefl_reg; 184 } 185 186 return 0; 187 188 error_disable_vrefl_reg: 189 if (state->vrefl_reg) 190 regulator_disable(state->vrefl_reg); 191 error_disable_vrefh_reg: 192 regulator_disable(state->vrefh_reg); 193 return ret; 194 } 195 196 static void ad8801_remove(struct spi_device *spi) 197 { 198 struct iio_dev *indio_dev = spi_get_drvdata(spi); 199 struct ad8801_state *state = iio_priv(indio_dev); 200 201 iio_device_unregister(indio_dev); 202 if (state->vrefl_reg) 203 regulator_disable(state->vrefl_reg); 204 regulator_disable(state->vrefh_reg); 205 } 206 207 static const struct spi_device_id ad8801_ids[] = { 208 {"ad8801", ID_AD8801}, 209 {"ad8803", ID_AD8803}, 210 {} 211 }; 212 MODULE_DEVICE_TABLE(spi, ad8801_ids); 213 214 static struct spi_driver ad8801_driver = { 215 .driver = { 216 .name = "ad8801", 217 }, 218 .probe = ad8801_probe, 219 .remove = ad8801_remove, 220 .id_table = ad8801_ids, 221 }; 222 module_spi_driver(ad8801_driver); 223 224 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>"); 225 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC"); 226 MODULE_LICENSE("GPL v2"); 227