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 .driver_module = THIS_MODULE, 96 }; 97 98 #define AD8801_CHANNEL(chan) { \ 99 .type = IIO_VOLTAGE, \ 100 .indexed = 1, \ 101 .output = 1, \ 102 .channel = chan, \ 103 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 104 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 105 BIT(IIO_CHAN_INFO_OFFSET), \ 106 } 107 108 static const struct iio_chan_spec ad8801_channels[] = { 109 AD8801_CHANNEL(0), 110 AD8801_CHANNEL(1), 111 AD8801_CHANNEL(2), 112 AD8801_CHANNEL(3), 113 AD8801_CHANNEL(4), 114 AD8801_CHANNEL(5), 115 AD8801_CHANNEL(6), 116 AD8801_CHANNEL(7), 117 }; 118 119 static int ad8801_probe(struct spi_device *spi) 120 { 121 struct iio_dev *indio_dev; 122 struct ad8801_state *state; 123 const struct spi_device_id *id; 124 int ret; 125 126 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 127 if (indio_dev == NULL) 128 return -ENOMEM; 129 130 state = iio_priv(indio_dev); 131 state->spi = spi; 132 id = spi_get_device_id(spi); 133 134 state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh"); 135 if (IS_ERR(state->vrefh_reg)) { 136 dev_err(&spi->dev, "Vrefh regulator not specified\n"); 137 return PTR_ERR(state->vrefh_reg); 138 } 139 140 ret = regulator_enable(state->vrefh_reg); 141 if (ret) { 142 dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n", 143 ret); 144 return ret; 145 } 146 147 ret = regulator_get_voltage(state->vrefh_reg); 148 if (ret < 0) { 149 dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n", 150 ret); 151 goto error_disable_vrefh_reg; 152 } 153 state->vrefh_mv = ret / 1000; 154 155 if (id->driver_data == ID_AD8803) { 156 state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl"); 157 if (IS_ERR(state->vrefl_reg)) { 158 dev_err(&spi->dev, "Vrefl regulator not specified\n"); 159 ret = PTR_ERR(state->vrefl_reg); 160 goto error_disable_vrefh_reg; 161 } 162 163 ret = regulator_enable(state->vrefl_reg); 164 if (ret) { 165 dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n", 166 ret); 167 goto error_disable_vrefh_reg; 168 } 169 170 ret = regulator_get_voltage(state->vrefl_reg); 171 if (ret < 0) { 172 dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n", 173 ret); 174 goto error_disable_vrefl_reg; 175 } 176 state->vrefl_mv = ret / 1000; 177 } else { 178 state->vrefl_mv = 0; 179 state->vrefl_reg = NULL; 180 } 181 182 spi_set_drvdata(spi, indio_dev); 183 indio_dev->dev.parent = &spi->dev; 184 indio_dev->info = &ad8801_info; 185 indio_dev->modes = INDIO_DIRECT_MODE; 186 indio_dev->channels = ad8801_channels; 187 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels); 188 indio_dev->name = id->name; 189 190 ret = iio_device_register(indio_dev); 191 if (ret) { 192 dev_err(&spi->dev, "Failed to register iio device: %d\n", 193 ret); 194 goto error_disable_vrefl_reg; 195 } 196 197 return 0; 198 199 error_disable_vrefl_reg: 200 if (state->vrefl_reg) 201 regulator_disable(state->vrefl_reg); 202 error_disable_vrefh_reg: 203 regulator_disable(state->vrefh_reg); 204 return ret; 205 } 206 207 static int ad8801_remove(struct spi_device *spi) 208 { 209 struct iio_dev *indio_dev = spi_get_drvdata(spi); 210 struct ad8801_state *state = iio_priv(indio_dev); 211 212 iio_device_unregister(indio_dev); 213 if (state->vrefl_reg) 214 regulator_disable(state->vrefl_reg); 215 regulator_disable(state->vrefh_reg); 216 217 return 0; 218 } 219 220 static const struct spi_device_id ad8801_ids[] = { 221 {"ad8801", ID_AD8801}, 222 {"ad8803", ID_AD8803}, 223 {} 224 }; 225 MODULE_DEVICE_TABLE(spi, ad8801_ids); 226 227 static struct spi_driver ad8801_driver = { 228 .driver = { 229 .name = "ad8801", 230 }, 231 .probe = ad8801_probe, 232 .remove = ad8801_remove, 233 .id_table = ad8801_ids, 234 }; 235 module_spi_driver(ad8801_driver); 236 237 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>"); 238 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC"); 239 MODULE_LICENSE("GPL v2"); 240