1 /* 2 * IIO DAC driver for Analog Devices AD8801 DAC 3 * 4 * Copyright (C) 2016 Gwenhael Goavec-Merou 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License, version 2, as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 */ 15 16 #include <linux/iio/iio.h> 17 #include <linux/module.h> 18 #include <linux/regulator/consumer.h> 19 #include <linux/spi/spi.h> 20 #include <linux/sysfs.h> 21 22 #define AD8801_CFG_ADDR_OFFSET 8 23 24 enum ad8801_device_ids { 25 ID_AD8801, 26 ID_AD8803, 27 }; 28 29 struct ad8801_state { 30 struct spi_device *spi; 31 unsigned char dac_cache[8]; /* Value write on each channel */ 32 unsigned int vrefh_mv; 33 unsigned int vrefl_mv; 34 struct regulator *vrefh_reg; 35 struct regulator *vrefl_reg; 36 37 __be16 data ____cacheline_aligned; 38 }; 39 40 static int ad8801_spi_write(struct ad8801_state *state, 41 u8 channel, unsigned char value) 42 { 43 state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value); 44 return spi_write(state->spi, &state->data, sizeof(state->data)); 45 } 46 47 static int ad8801_write_raw(struct iio_dev *indio_dev, 48 struct iio_chan_spec const *chan, int val, int val2, long mask) 49 { 50 struct ad8801_state *state = iio_priv(indio_dev); 51 int ret; 52 53 switch (mask) { 54 case IIO_CHAN_INFO_RAW: 55 if (val >= 256 || val < 0) 56 return -EINVAL; 57 58 ret = ad8801_spi_write(state, chan->channel, val); 59 if (ret == 0) 60 state->dac_cache[chan->channel] = val; 61 break; 62 default: 63 ret = -EINVAL; 64 } 65 66 return ret; 67 } 68 69 static int ad8801_read_raw(struct iio_dev *indio_dev, 70 struct iio_chan_spec const *chan, int *val, int *val2, long info) 71 { 72 struct ad8801_state *state = iio_priv(indio_dev); 73 74 switch (info) { 75 case IIO_CHAN_INFO_RAW: 76 *val = state->dac_cache[chan->channel]; 77 return IIO_VAL_INT; 78 case IIO_CHAN_INFO_SCALE: 79 *val = state->vrefh_mv - state->vrefl_mv; 80 *val2 = 8; 81 return IIO_VAL_FRACTIONAL_LOG2; 82 case IIO_CHAN_INFO_OFFSET: 83 *val = state->vrefl_mv; 84 return IIO_VAL_INT; 85 default: 86 return -EINVAL; 87 } 88 89 return -EINVAL; 90 } 91 92 static const struct iio_info ad8801_info = { 93 .read_raw = ad8801_read_raw, 94 .write_raw = ad8801_write_raw, 95 }; 96 97 #define AD8801_CHANNEL(chan) { \ 98 .type = IIO_VOLTAGE, \ 99 .indexed = 1, \ 100 .output = 1, \ 101 .channel = chan, \ 102 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 103 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 104 BIT(IIO_CHAN_INFO_OFFSET), \ 105 } 106 107 static const struct iio_chan_spec ad8801_channels[] = { 108 AD8801_CHANNEL(0), 109 AD8801_CHANNEL(1), 110 AD8801_CHANNEL(2), 111 AD8801_CHANNEL(3), 112 AD8801_CHANNEL(4), 113 AD8801_CHANNEL(5), 114 AD8801_CHANNEL(6), 115 AD8801_CHANNEL(7), 116 }; 117 118 static int ad8801_probe(struct spi_device *spi) 119 { 120 struct iio_dev *indio_dev; 121 struct ad8801_state *state; 122 const struct spi_device_id *id; 123 int ret; 124 125 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 126 if (indio_dev == NULL) 127 return -ENOMEM; 128 129 state = iio_priv(indio_dev); 130 state->spi = spi; 131 id = spi_get_device_id(spi); 132 133 state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh"); 134 if (IS_ERR(state->vrefh_reg)) { 135 dev_err(&spi->dev, "Vrefh regulator not specified\n"); 136 return PTR_ERR(state->vrefh_reg); 137 } 138 139 ret = regulator_enable(state->vrefh_reg); 140 if (ret) { 141 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n", 142 ret); 143 return ret; 144 } 145 146 ret = regulator_get_voltage(state->vrefh_reg); 147 if (ret < 0) { 148 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n", 149 ret); 150 goto error_disable_vrefh_reg; 151 } 152 state->vrefh_mv = ret / 1000; 153 154 if (id->driver_data == ID_AD8803) { 155 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl"); 156 if (IS_ERR(state->vrefl_reg)) { 157 dev_err(&spi->dev, "Vrefl regulator not specified\n"); 158 ret = PTR_ERR(state->vrefl_reg); 159 goto error_disable_vrefh_reg; 160 } 161 162 ret = regulator_enable(state->vrefl_reg); 163 if (ret) { 164 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n", 165 ret); 166 goto error_disable_vrefh_reg; 167 } 168 169 ret = regulator_get_voltage(state->vrefl_reg); 170 if (ret < 0) { 171 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n", 172 ret); 173 goto error_disable_vrefl_reg; 174 } 175 state->vrefl_mv = ret / 1000; 176 } else { 177 state->vrefl_mv = 0; 178 state->vrefl_reg = NULL; 179 } 180 181 spi_set_drvdata(spi, indio_dev); 182 indio_dev->dev.parent = &spi->dev; 183 indio_dev->info = &ad8801_info; 184 indio_dev->modes = INDIO_DIRECT_MODE; 185 indio_dev->channels = ad8801_channels; 186 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels); 187 indio_dev->name = id->name; 188 189 ret = iio_device_register(indio_dev); 190 if (ret) { 191 dev_err(&spi->dev, "Failed to register iio device: %d\n", 192 ret); 193 goto error_disable_vrefl_reg; 194 } 195 196 return 0; 197 198 error_disable_vrefl_reg: 199 if (state->vrefl_reg) 200 regulator_disable(state->vrefl_reg); 201 error_disable_vrefh_reg: 202 regulator_disable(state->vrefh_reg); 203 return ret; 204 } 205 206 static int ad8801_remove(struct spi_device *spi) 207 { 208 struct iio_dev *indio_dev = spi_get_drvdata(spi); 209 struct ad8801_state *state = iio_priv(indio_dev); 210 211 iio_device_unregister(indio_dev); 212 if (state->vrefl_reg) 213 regulator_disable(state->vrefl_reg); 214 regulator_disable(state->vrefh_reg); 215 216 return 0; 217 } 218 219 static const struct spi_device_id ad8801_ids[] = { 220 {"ad8801", ID_AD8801}, 221 {"ad8803", ID_AD8803}, 222 {} 223 }; 224 MODULE_DEVICE_TABLE(spi, ad8801_ids); 225 226 static struct spi_driver ad8801_driver = { 227 .driver = { 228 .name = "ad8801", 229 }, 230 .probe = ad8801_probe, 231 .remove = ad8801_remove, 232 .id_table = ad8801_ids, 233 }; 234 module_spi_driver(ad8801_driver); 235 236 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>"); 237 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC"); 238 MODULE_LICENSE("GPL v2"); 239