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 #include <linux/of.h> 16 17 #include <linux/iio/iio.h> 18 #include <linux/iio/sysfs.h> 19 20 #include <linux/platform_data/ad7303.h> 21 22 #define AD7303_CFG_EXTERNAL_VREF BIT(15) 23 #define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch)) 24 #define AD7303_CFG_ADDR_OFFSET 10 25 26 #define AD7303_CMD_UPDATE_DAC (0x3 << 8) 27 28 /** 29 * struct ad7303_state - driver instance specific data 30 * @spi: the device for this driver instance 31 * @config: cached config register value 32 * @dac_cache: current DAC raw value (chip does not support readback) 33 * @data: spi transfer buffer 34 */ 35 36 struct ad7303_state { 37 struct spi_device *spi; 38 uint16_t config; 39 uint8_t dac_cache[2]; 40 41 struct regulator *vdd_reg; 42 struct regulator *vref_reg; 43 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(&indio_dev->mlock); 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(&indio_dev->mlock); 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 *val = st->dac_cache[chan->channel]; 120 return IIO_VAL_INT; 121 case IIO_CHAN_INFO_SCALE: 122 vref_uv = ad7303_get_vref(st, chan); 123 if (vref_uv < 0) 124 return vref_uv; 125 126 *val = 2 * vref_uv / 1000; 127 *val2 = chan->scan_type.realbits; 128 129 return IIO_VAL_FRACTIONAL_LOG2; 130 default: 131 break; 132 } 133 return -EINVAL; 134 } 135 136 static int ad7303_write_raw(struct iio_dev *indio_dev, 137 struct iio_chan_spec const *chan, int val, int val2, long mask) 138 { 139 struct ad7303_state *st = iio_priv(indio_dev); 140 int ret; 141 142 switch (mask) { 143 case IIO_CHAN_INFO_RAW: 144 if (val >= (1 << chan->scan_type.realbits) || val < 0) 145 return -EINVAL; 146 147 mutex_lock(&indio_dev->mlock); 148 ret = ad7303_write(st, chan->address, val); 149 if (ret == 0) 150 st->dac_cache[chan->channel] = val; 151 mutex_unlock(&indio_dev->mlock); 152 break; 153 default: 154 ret = -EINVAL; 155 } 156 157 return ret; 158 } 159 160 static const struct iio_info ad7303_info = { 161 .read_raw = ad7303_read_raw, 162 .write_raw = ad7303_write_raw, 163 }; 164 165 static const struct iio_chan_spec_ext_info ad7303_ext_info[] = { 166 { 167 .name = "powerdown", 168 .read = ad7303_read_dac_powerdown, 169 .write = ad7303_write_dac_powerdown, 170 .shared = IIO_SEPARATE, 171 }, 172 { }, 173 }; 174 175 #define AD7303_CHANNEL(chan) { \ 176 .type = IIO_VOLTAGE, \ 177 .indexed = 1, \ 178 .output = 1, \ 179 .channel = (chan), \ 180 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 181 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 182 .address = (chan), \ 183 .scan_type = { \ 184 .sign = 'u', \ 185 .realbits = 8, \ 186 .storagebits = 8, \ 187 .shift = 0, \ 188 }, \ 189 .ext_info = ad7303_ext_info, \ 190 } 191 192 static const struct iio_chan_spec ad7303_channels[] = { 193 AD7303_CHANNEL(0), 194 AD7303_CHANNEL(1), 195 }; 196 197 static int ad7303_probe(struct spi_device *spi) 198 { 199 const struct spi_device_id *id = spi_get_device_id(spi); 200 struct iio_dev *indio_dev; 201 struct ad7303_state *st; 202 bool ext_ref; 203 int ret; 204 205 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 206 if (indio_dev == NULL) 207 return -ENOMEM; 208 209 st = iio_priv(indio_dev); 210 spi_set_drvdata(spi, indio_dev); 211 212 st->spi = spi; 213 214 st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); 215 if (IS_ERR(st->vdd_reg)) 216 return PTR_ERR(st->vdd_reg); 217 218 ret = regulator_enable(st->vdd_reg); 219 if (ret) 220 return ret; 221 222 if (spi->dev.of_node) { 223 ext_ref = of_property_read_bool(spi->dev.of_node, 224 "REF-supply"); 225 } else { 226 struct ad7303_platform_data *pdata = spi->dev.platform_data; 227 if (pdata && pdata->use_external_ref) 228 ext_ref = true; 229 else 230 ext_ref = false; 231 } 232 233 if (ext_ref) { 234 st->vref_reg = devm_regulator_get(&spi->dev, "REF"); 235 if (IS_ERR(st->vref_reg)) { 236 ret = PTR_ERR(st->vref_reg); 237 goto err_disable_vdd_reg; 238 } 239 240 ret = regulator_enable(st->vref_reg); 241 if (ret) 242 goto err_disable_vdd_reg; 243 244 st->config |= AD7303_CFG_EXTERNAL_VREF; 245 } 246 247 indio_dev->dev.parent = &spi->dev; 248 indio_dev->name = id->name; 249 indio_dev->info = &ad7303_info; 250 indio_dev->modes = INDIO_DIRECT_MODE; 251 indio_dev->channels = ad7303_channels; 252 indio_dev->num_channels = ARRAY_SIZE(ad7303_channels); 253 254 ret = iio_device_register(indio_dev); 255 if (ret) 256 goto err_disable_vref_reg; 257 258 return 0; 259 260 err_disable_vref_reg: 261 if (st->vref_reg) 262 regulator_disable(st->vref_reg); 263 err_disable_vdd_reg: 264 regulator_disable(st->vdd_reg); 265 return ret; 266 } 267 268 static int ad7303_remove(struct spi_device *spi) 269 { 270 struct iio_dev *indio_dev = spi_get_drvdata(spi); 271 struct ad7303_state *st = iio_priv(indio_dev); 272 273 iio_device_unregister(indio_dev); 274 275 if (st->vref_reg) 276 regulator_disable(st->vref_reg); 277 regulator_disable(st->vdd_reg); 278 279 return 0; 280 } 281 282 static const struct of_device_id ad7303_spi_of_match[] = { 283 { .compatible = "adi,ad7303", }, 284 { /* sentinel */ }, 285 }; 286 MODULE_DEVICE_TABLE(of, ad7303_spi_of_match); 287 288 static const struct spi_device_id ad7303_spi_ids[] = { 289 { "ad7303", 0 }, 290 {} 291 }; 292 MODULE_DEVICE_TABLE(spi, ad7303_spi_ids); 293 294 static struct spi_driver ad7303_driver = { 295 .driver = { 296 .name = "ad7303", 297 .of_match_table = of_match_ptr(ad7303_spi_of_match), 298 }, 299 .probe = ad7303_probe, 300 .remove = ad7303_remove, 301 .id_table = ad7303_spi_ids, 302 }; 303 module_spi_driver(ad7303_driver); 304 305 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 306 MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver"); 307 MODULE_LICENSE("GPL v2"); 308