1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AD7303 Digital to analog converters driver 4 * 5 * Copyright 2013 Analog Devices Inc. 6 */ 7 8 #include <linux/err.h> 9 #include <linux/module.h> 10 #include <linux/kernel.h> 11 #include <linux/spi/spi.h> 12 #include <linux/slab.h> 13 #include <linux/sysfs.h> 14 #include <linux/regulator/consumer.h> 15 16 #include <linux/iio/iio.h> 17 #include <linux/iio/sysfs.h> 18 19 #include <linux/platform_data/ad7303.h> 20 21 #define AD7303_CFG_EXTERNAL_VREF BIT(15) 22 #define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch)) 23 #define AD7303_CFG_ADDR_OFFSET 10 24 25 #define AD7303_CMD_UPDATE_DAC (0x3 << 8) 26 27 /** 28 * struct ad7303_state - driver instance specific data 29 * @spi: the device for this driver instance 30 * @config: cached config register value 31 * @dac_cache: current DAC raw value (chip does not support readback) 32 * @data: spi transfer buffer 33 */ 34 35 struct ad7303_state { 36 struct spi_device *spi; 37 uint16_t config; 38 uint8_t dac_cache[2]; 39 40 struct regulator *vdd_reg; 41 struct regulator *vref_reg; 42 43 struct mutex lock; 44 /* 45 * DMA (thus cache coherency maintenance) requires the 46 * transfer buffers to live in their own cache lines. 47 */ 48 __be16 data ____cacheline_aligned; 49 }; 50 51 static int ad7303_write(struct ad7303_state *st, unsigned int chan, 52 uint8_t val) 53 { 54 st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC | 55 (chan << AD7303_CFG_ADDR_OFFSET) | 56 st->config | val); 57 58 return spi_write(st->spi, &st->data, sizeof(st->data)); 59 } 60 61 static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev, 62 uintptr_t private, const struct iio_chan_spec *chan, char *buf) 63 { 64 struct ad7303_state *st = iio_priv(indio_dev); 65 66 return sprintf(buf, "%d\n", (bool)(st->config & 67 AD7303_CFG_POWER_DOWN(chan->channel))); 68 } 69 70 static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, 71 uintptr_t private, const struct iio_chan_spec *chan, const char *buf, 72 size_t len) 73 { 74 struct ad7303_state *st = iio_priv(indio_dev); 75 bool pwr_down; 76 int ret; 77 78 ret = strtobool(buf, &pwr_down); 79 if (ret) 80 return ret; 81 82 mutex_lock(&st->lock); 83 84 if (pwr_down) 85 st->config |= AD7303_CFG_POWER_DOWN(chan->channel); 86 else 87 st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel); 88 89 /* There is no noop cmd which allows us to only update the powerdown 90 * mode, so just write one of the DAC channels again */ 91 ad7303_write(st, chan->channel, st->dac_cache[chan->channel]); 92 93 mutex_unlock(&st->lock); 94 return len; 95 } 96 97 static int ad7303_get_vref(struct ad7303_state *st, 98 struct iio_chan_spec const *chan) 99 { 100 int ret; 101 102 if (st->config & AD7303_CFG_EXTERNAL_VREF) 103 return regulator_get_voltage(st->vref_reg); 104 105 ret = regulator_get_voltage(st->vdd_reg); 106 if (ret < 0) 107 return ret; 108 return ret / 2; 109 } 110 111 static int ad7303_read_raw(struct iio_dev *indio_dev, 112 struct iio_chan_spec const *chan, int *val, int *val2, long info) 113 { 114 struct ad7303_state *st = iio_priv(indio_dev); 115 int vref_uv; 116 117 switch (info) { 118 case IIO_CHAN_INFO_RAW: 119 mutex_lock(&st->lock); 120 *val = st->dac_cache[chan->channel]; 121 mutex_unlock(&st->lock); 122 return IIO_VAL_INT; 123 case IIO_CHAN_INFO_SCALE: 124 vref_uv = ad7303_get_vref(st, chan); 125 if (vref_uv < 0) 126 return vref_uv; 127 128 *val = 2 * vref_uv / 1000; 129 *val2 = chan->scan_type.realbits; 130 131 return IIO_VAL_FRACTIONAL_LOG2; 132 default: 133 break; 134 } 135 return -EINVAL; 136 } 137 138 static int ad7303_write_raw(struct iio_dev *indio_dev, 139 struct iio_chan_spec const *chan, int val, int val2, long mask) 140 { 141 struct ad7303_state *st = iio_priv(indio_dev); 142 int ret; 143 144 switch (mask) { 145 case IIO_CHAN_INFO_RAW: 146 if (val >= (1 << chan->scan_type.realbits) || val < 0) 147 return -EINVAL; 148 149 mutex_lock(&st->lock); 150 ret = ad7303_write(st, chan->address, val); 151 if (ret == 0) 152 st->dac_cache[chan->channel] = val; 153 mutex_unlock(&st->lock); 154 break; 155 default: 156 ret = -EINVAL; 157 } 158 159 return ret; 160 } 161 162 static const struct iio_info ad7303_info = { 163 .read_raw = ad7303_read_raw, 164 .write_raw = ad7303_write_raw, 165 }; 166 167 static const struct iio_chan_spec_ext_info ad7303_ext_info[] = { 168 { 169 .name = "powerdown", 170 .read = ad7303_read_dac_powerdown, 171 .write = ad7303_write_dac_powerdown, 172 .shared = IIO_SEPARATE, 173 }, 174 { }, 175 }; 176 177 #define AD7303_CHANNEL(chan) { \ 178 .type = IIO_VOLTAGE, \ 179 .indexed = 1, \ 180 .output = 1, \ 181 .channel = (chan), \ 182 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 183 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 184 .address = (chan), \ 185 .scan_type = { \ 186 .sign = 'u', \ 187 .realbits = 8, \ 188 .storagebits = 8, \ 189 .shift = 0, \ 190 }, \ 191 .ext_info = ad7303_ext_info, \ 192 } 193 194 static const struct iio_chan_spec ad7303_channels[] = { 195 AD7303_CHANNEL(0), 196 AD7303_CHANNEL(1), 197 }; 198 199 static int ad7303_probe(struct spi_device *spi) 200 { 201 const struct spi_device_id *id = spi_get_device_id(spi); 202 struct iio_dev *indio_dev; 203 struct ad7303_state *st; 204 int ret; 205 206 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 207 if (indio_dev == NULL) 208 return -ENOMEM; 209 210 st = iio_priv(indio_dev); 211 spi_set_drvdata(spi, indio_dev); 212 213 st->spi = spi; 214 215 mutex_init(&st->lock); 216 217 st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); 218 if (IS_ERR(st->vdd_reg)) 219 return PTR_ERR(st->vdd_reg); 220 221 ret = regulator_enable(st->vdd_reg); 222 if (ret) 223 return ret; 224 225 st->vref_reg = devm_regulator_get_optional(&spi->dev, "REF"); 226 if (IS_ERR(st->vref_reg)) { 227 ret = PTR_ERR(st->vref_reg); 228 if (ret != -ENODEV) 229 goto err_disable_vdd_reg; 230 st->vref_reg = NULL; 231 } 232 233 if (st->vref_reg) { 234 ret = regulator_enable(st->vref_reg); 235 if (ret) 236 goto err_disable_vdd_reg; 237 238 st->config |= AD7303_CFG_EXTERNAL_VREF; 239 } 240 241 indio_dev->name = id->name; 242 indio_dev->info = &ad7303_info; 243 indio_dev->modes = INDIO_DIRECT_MODE; 244 indio_dev->channels = ad7303_channels; 245 indio_dev->num_channels = ARRAY_SIZE(ad7303_channels); 246 247 ret = iio_device_register(indio_dev); 248 if (ret) 249 goto err_disable_vref_reg; 250 251 return 0; 252 253 err_disable_vref_reg: 254 if (st->vref_reg) 255 regulator_disable(st->vref_reg); 256 err_disable_vdd_reg: 257 regulator_disable(st->vdd_reg); 258 return ret; 259 } 260 261 static int ad7303_remove(struct spi_device *spi) 262 { 263 struct iio_dev *indio_dev = spi_get_drvdata(spi); 264 struct ad7303_state *st = iio_priv(indio_dev); 265 266 iio_device_unregister(indio_dev); 267 268 if (st->vref_reg) 269 regulator_disable(st->vref_reg); 270 regulator_disable(st->vdd_reg); 271 272 return 0; 273 } 274 275 static const struct of_device_id ad7303_spi_of_match[] = { 276 { .compatible = "adi,ad7303", }, 277 { /* sentinel */ }, 278 }; 279 MODULE_DEVICE_TABLE(of, ad7303_spi_of_match); 280 281 static const struct spi_device_id ad7303_spi_ids[] = { 282 { "ad7303", 0 }, 283 {} 284 }; 285 MODULE_DEVICE_TABLE(spi, ad7303_spi_ids); 286 287 static struct spi_driver ad7303_driver = { 288 .driver = { 289 .name = "ad7303", 290 .of_match_table = of_match_ptr(ad7303_spi_of_match), 291 }, 292 .probe = ad7303_probe, 293 .remove = ad7303_remove, 294 .id_table = ad7303_spi_ids, 295 }; 296 module_spi_driver(ad7303_driver); 297 298 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 299 MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver"); 300 MODULE_LICENSE("GPL v2"); 301