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 27 __be16 data __aligned(IIO_DMA_MINALIGN); 28 }; 29 30 static int ad8801_spi_write(struct ad8801_state *state, 31 u8 channel, unsigned char value) 32 { 33 state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value); 34 return spi_write(state->spi, &state->data, sizeof(state->data)); 35 } 36 37 static int ad8801_write_raw(struct iio_dev *indio_dev, 38 struct iio_chan_spec const *chan, int val, int val2, long mask) 39 { 40 struct ad8801_state *state = iio_priv(indio_dev); 41 int ret; 42 43 switch (mask) { 44 case IIO_CHAN_INFO_RAW: 45 if (val >= 256 || val < 0) 46 return -EINVAL; 47 48 ret = ad8801_spi_write(state, chan->channel, val); 49 if (ret == 0) 50 state->dac_cache[chan->channel] = val; 51 break; 52 default: 53 ret = -EINVAL; 54 } 55 56 return ret; 57 } 58 59 static int ad8801_read_raw(struct iio_dev *indio_dev, 60 struct iio_chan_spec const *chan, int *val, int *val2, long info) 61 { 62 struct ad8801_state *state = iio_priv(indio_dev); 63 64 switch (info) { 65 case IIO_CHAN_INFO_RAW: 66 *val = state->dac_cache[chan->channel]; 67 return IIO_VAL_INT; 68 case IIO_CHAN_INFO_SCALE: 69 *val = state->vrefh_mv - state->vrefl_mv; 70 *val2 = 8; 71 return IIO_VAL_FRACTIONAL_LOG2; 72 case IIO_CHAN_INFO_OFFSET: 73 *val = state->vrefl_mv; 74 return IIO_VAL_INT; 75 default: 76 return -EINVAL; 77 } 78 79 return -EINVAL; 80 } 81 82 static const struct iio_info ad8801_info = { 83 .read_raw = ad8801_read_raw, 84 .write_raw = ad8801_write_raw, 85 }; 86 87 #define AD8801_CHANNEL(chan) { \ 88 .type = IIO_VOLTAGE, \ 89 .indexed = 1, \ 90 .output = 1, \ 91 .channel = chan, \ 92 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 93 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 94 BIT(IIO_CHAN_INFO_OFFSET), \ 95 } 96 97 static const struct iio_chan_spec ad8801_channels[] = { 98 AD8801_CHANNEL(0), 99 AD8801_CHANNEL(1), 100 AD8801_CHANNEL(2), 101 AD8801_CHANNEL(3), 102 AD8801_CHANNEL(4), 103 AD8801_CHANNEL(5), 104 AD8801_CHANNEL(6), 105 AD8801_CHANNEL(7), 106 }; 107 108 static int ad8801_probe(struct spi_device *spi) 109 { 110 struct iio_dev *indio_dev; 111 struct ad8801_state *state; 112 const struct spi_device_id *id; 113 int ret; 114 115 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 116 if (indio_dev == NULL) 117 return -ENOMEM; 118 119 state = iio_priv(indio_dev); 120 state->spi = spi; 121 id = spi_get_device_id(spi); 122 123 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefh"); 124 if (ret < 0) 125 return dev_err_probe(&spi->dev, ret, 126 "failed to get Vrefh voltage\n"); 127 128 state->vrefh_mv = ret / 1000; 129 130 if (id->driver_data == ID_AD8803) { 131 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefl"); 132 if (ret < 0) 133 return dev_err_probe(&spi->dev, ret, 134 "failed to get Vrefl voltage\n"); 135 136 state->vrefl_mv = ret / 1000; 137 } 138 139 indio_dev->info = &ad8801_info; 140 indio_dev->modes = INDIO_DIRECT_MODE; 141 indio_dev->channels = ad8801_channels; 142 indio_dev->num_channels = ARRAY_SIZE(ad8801_channels); 143 indio_dev->name = id->name; 144 145 ret = devm_iio_device_register(&spi->dev, indio_dev); 146 if (ret) 147 return dev_err_probe(&spi->dev, ret, 148 "Failed to register iio device\n"); 149 150 return 0; 151 } 152 153 static const struct spi_device_id ad8801_ids[] = { 154 {"ad8801", ID_AD8801}, 155 {"ad8803", ID_AD8803}, 156 {} 157 }; 158 MODULE_DEVICE_TABLE(spi, ad8801_ids); 159 160 static struct spi_driver ad8801_driver = { 161 .driver = { 162 .name = "ad8801", 163 }, 164 .probe = ad8801_probe, 165 .id_table = ad8801_ids, 166 }; 167 module_spi_driver(ad8801_driver); 168 169 MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>"); 170 MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC"); 171 MODULE_LICENSE("GPL v2"); 172