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 struct mutex lock; 45 /* 46 * DMA (thus cache coherency maintenance) requires the 47 * transfer buffers to live in their own cache lines. 48 */ 49 __be16 data ____cacheline_aligned; 50 }; 51 52 static int ad7303_write(struct ad7303_state *st, unsigned int chan, 53 uint8_t val) 54 { 55 st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC | 56 (chan << AD7303_CFG_ADDR_OFFSET) | 57 st->config | val); 58 59 return spi_write(st->spi, &st->data, sizeof(st->data)); 60 } 61 62 static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev, 63 uintptr_t private, const struct iio_chan_spec *chan, char *buf) 64 { 65 struct ad7303_state *st = iio_priv(indio_dev); 66 67 return sprintf(buf, "%d\n", (bool)(st->config & 68 AD7303_CFG_POWER_DOWN(chan->channel))); 69 } 70 71 static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, 72 uintptr_t private, const struct iio_chan_spec *chan, const char *buf, 73 size_t len) 74 { 75 struct ad7303_state *st = iio_priv(indio_dev); 76 bool pwr_down; 77 int ret; 78 79 ret = strtobool(buf, &pwr_down); 80 if (ret) 81 return ret; 82 83 mutex_lock(&st->lock); 84 85 if (pwr_down) 86 st->config |= AD7303_CFG_POWER_DOWN(chan->channel); 87 else 88 st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel); 89 90 /* There is no noop cmd which allows us to only update the powerdown 91 * mode, so just write one of the DAC channels again */ 92 ad7303_write(st, chan->channel, st->dac_cache[chan->channel]); 93 94 mutex_unlock(&st->lock); 95 return len; 96 } 97 98 static int ad7303_get_vref(struct ad7303_state *st, 99 struct iio_chan_spec const *chan) 100 { 101 int ret; 102 103 if (st->config & AD7303_CFG_EXTERNAL_VREF) 104 return regulator_get_voltage(st->vref_reg); 105 106 ret = regulator_get_voltage(st->vdd_reg); 107 if (ret < 0) 108 return ret; 109 return ret / 2; 110 } 111 112 static int ad7303_read_raw(struct iio_dev *indio_dev, 113 struct iio_chan_spec const *chan, int *val, int *val2, long info) 114 { 115 struct ad7303_state *st = iio_priv(indio_dev); 116 int vref_uv; 117 118 switch (info) { 119 case IIO_CHAN_INFO_RAW: 120 mutex_lock(&st->lock); 121 *val = st->dac_cache[chan->channel]; 122 mutex_unlock(&st->lock); 123 return IIO_VAL_INT; 124 case IIO_CHAN_INFO_SCALE: 125 vref_uv = ad7303_get_vref(st, chan); 126 if (vref_uv < 0) 127 return vref_uv; 128 129 *val = 2 * vref_uv / 1000; 130 *val2 = chan->scan_type.realbits; 131 132 return IIO_VAL_FRACTIONAL_LOG2; 133 default: 134 break; 135 } 136 return -EINVAL; 137 } 138 139 static int ad7303_write_raw(struct iio_dev *indio_dev, 140 struct iio_chan_spec const *chan, int val, int val2, long mask) 141 { 142 struct ad7303_state *st = iio_priv(indio_dev); 143 int ret; 144 145 switch (mask) { 146 case IIO_CHAN_INFO_RAW: 147 if (val >= (1 << chan->scan_type.realbits) || val < 0) 148 return -EINVAL; 149 150 mutex_lock(&st->lock); 151 ret = ad7303_write(st, chan->address, val); 152 if (ret == 0) 153 st->dac_cache[chan->channel] = val; 154 mutex_unlock(&st->lock); 155 break; 156 default: 157 ret = -EINVAL; 158 } 159 160 return ret; 161 } 162 163 static const struct iio_info ad7303_info = { 164 .read_raw = ad7303_read_raw, 165 .write_raw = ad7303_write_raw, 166 }; 167 168 static const struct iio_chan_spec_ext_info ad7303_ext_info[] = { 169 { 170 .name = "powerdown", 171 .read = ad7303_read_dac_powerdown, 172 .write = ad7303_write_dac_powerdown, 173 .shared = IIO_SEPARATE, 174 }, 175 { }, 176 }; 177 178 #define AD7303_CHANNEL(chan) { \ 179 .type = IIO_VOLTAGE, \ 180 .indexed = 1, \ 181 .output = 1, \ 182 .channel = (chan), \ 183 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 184 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 185 .address = (chan), \ 186 .scan_type = { \ 187 .sign = 'u', \ 188 .realbits = 8, \ 189 .storagebits = 8, \ 190 .shift = 0, \ 191 }, \ 192 .ext_info = ad7303_ext_info, \ 193 } 194 195 static const struct iio_chan_spec ad7303_channels[] = { 196 AD7303_CHANNEL(0), 197 AD7303_CHANNEL(1), 198 }; 199 200 static int ad7303_probe(struct spi_device *spi) 201 { 202 const struct spi_device_id *id = spi_get_device_id(spi); 203 struct iio_dev *indio_dev; 204 struct ad7303_state *st; 205 bool ext_ref; 206 int ret; 207 208 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 209 if (indio_dev == NULL) 210 return -ENOMEM; 211 212 st = iio_priv(indio_dev); 213 spi_set_drvdata(spi, indio_dev); 214 215 st->spi = spi; 216 217 mutex_init(&st->lock); 218 219 st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); 220 if (IS_ERR(st->vdd_reg)) 221 return PTR_ERR(st->vdd_reg); 222 223 ret = regulator_enable(st->vdd_reg); 224 if (ret) 225 return ret; 226 227 if (spi->dev.of_node) { 228 ext_ref = of_property_read_bool(spi->dev.of_node, 229 "REF-supply"); 230 } else { 231 struct ad7303_platform_data *pdata = spi->dev.platform_data; 232 if (pdata && pdata->use_external_ref) 233 ext_ref = true; 234 else 235 ext_ref = false; 236 } 237 238 if (ext_ref) { 239 st->vref_reg = devm_regulator_get(&spi->dev, "REF"); 240 if (IS_ERR(st->vref_reg)) { 241 ret = PTR_ERR(st->vref_reg); 242 goto err_disable_vdd_reg; 243 } 244 245 ret = regulator_enable(st->vref_reg); 246 if (ret) 247 goto err_disable_vdd_reg; 248 249 st->config |= AD7303_CFG_EXTERNAL_VREF; 250 } 251 252 indio_dev->dev.parent = &spi->dev; 253 indio_dev->name = id->name; 254 indio_dev->info = &ad7303_info; 255 indio_dev->modes = INDIO_DIRECT_MODE; 256 indio_dev->channels = ad7303_channels; 257 indio_dev->num_channels = ARRAY_SIZE(ad7303_channels); 258 259 ret = iio_device_register(indio_dev); 260 if (ret) 261 goto err_disable_vref_reg; 262 263 return 0; 264 265 err_disable_vref_reg: 266 if (st->vref_reg) 267 regulator_disable(st->vref_reg); 268 err_disable_vdd_reg: 269 regulator_disable(st->vdd_reg); 270 return ret; 271 } 272 273 static int ad7303_remove(struct spi_device *spi) 274 { 275 struct iio_dev *indio_dev = spi_get_drvdata(spi); 276 struct ad7303_state *st = iio_priv(indio_dev); 277 278 iio_device_unregister(indio_dev); 279 280 if (st->vref_reg) 281 regulator_disable(st->vref_reg); 282 regulator_disable(st->vdd_reg); 283 284 return 0; 285 } 286 287 static const struct of_device_id ad7303_spi_of_match[] = { 288 { .compatible = "adi,ad7303", }, 289 { /* sentinel */ }, 290 }; 291 MODULE_DEVICE_TABLE(of, ad7303_spi_of_match); 292 293 static const struct spi_device_id ad7303_spi_ids[] = { 294 { "ad7303", 0 }, 295 {} 296 }; 297 MODULE_DEVICE_TABLE(spi, ad7303_spi_ids); 298 299 static struct spi_driver ad7303_driver = { 300 .driver = { 301 .name = "ad7303", 302 .of_match_table = of_match_ptr(ad7303_spi_of_match), 303 }, 304 .probe = ad7303_probe, 305 .remove = ad7303_remove, 306 .id_table = ad7303_spi_ids, 307 }; 308 module_spi_driver(ad7303_driver); 309 310 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 311 MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver"); 312 MODULE_LICENSE("GPL v2"); 313