1 /* 2 * AD7303 Digital to analog converters driver 3 * 4 * Copyright 2013 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2. 7 */ 8 9 #include <linux/err.h> 10 #include <linux/module.h> 11 #include <linux/kernel.h> 12 #include <linux/spi/spi.h> 13 #include <linux/slab.h> 14 #include <linux/sysfs.h> 15 #include <linux/regulator/consumer.h> 16 #include <linux/of.h> 17 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 21 #include <linux/platform_data/ad7303.h> 22 23 #define AD7303_CFG_EXTERNAL_VREF BIT(15) 24 #define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch)) 25 #define AD7303_CFG_ADDR_OFFSET 10 26 27 #define AD7303_CMD_UPDATE_DAC (0x3 << 8) 28 29 /** 30 * struct ad7303_state - driver instance specific data 31 * @spi: the device for this driver instance 32 * @config: cached config register value 33 * @dac_cache: current DAC raw value (chip does not support readback) 34 * @data: spi transfer buffer 35 */ 36 37 struct ad7303_state { 38 struct spi_device *spi; 39 uint16_t config; 40 uint8_t dac_cache[2]; 41 42 struct regulator *vdd_reg; 43 struct regulator *vref_reg; 44 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(&indio_dev->mlock); 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(&indio_dev->mlock); 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 *val = st->dac_cache[chan->channel]; 121 return IIO_VAL_INT; 122 case IIO_CHAN_INFO_SCALE: 123 vref_uv = ad7303_get_vref(st, chan); 124 if (vref_uv < 0) 125 return vref_uv; 126 127 *val = 2 * vref_uv / 1000; 128 *val2 = chan->scan_type.realbits; 129 130 return IIO_VAL_FRACTIONAL_LOG2; 131 default: 132 break; 133 } 134 return -EINVAL; 135 } 136 137 static int ad7303_write_raw(struct iio_dev *indio_dev, 138 struct iio_chan_spec const *chan, int val, int val2, long mask) 139 { 140 struct ad7303_state *st = iio_priv(indio_dev); 141 int ret; 142 143 switch (mask) { 144 case IIO_CHAN_INFO_RAW: 145 if (val >= (1 << chan->scan_type.realbits) || val < 0) 146 return -EINVAL; 147 148 mutex_lock(&indio_dev->mlock); 149 ret = ad7303_write(st, chan->address, val); 150 if (ret == 0) 151 st->dac_cache[chan->channel] = val; 152 mutex_unlock(&indio_dev->mlock); 153 break; 154 default: 155 ret = -EINVAL; 156 } 157 158 return ret; 159 } 160 161 static const struct iio_info ad7303_info = { 162 .read_raw = ad7303_read_raw, 163 .write_raw = ad7303_write_raw, 164 .driver_module = THIS_MODULE, 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 bool ext_ref; 205 int ret; 206 207 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 208 if (indio_dev == NULL) 209 return -ENOMEM; 210 211 st = iio_priv(indio_dev); 212 spi_set_drvdata(spi, indio_dev); 213 214 st->spi = spi; 215 216 st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); 217 if (IS_ERR(st->vdd_reg)) 218 return PTR_ERR(st->vdd_reg); 219 220 ret = regulator_enable(st->vdd_reg); 221 if (ret) 222 return ret; 223 224 if (spi->dev.of_node) { 225 ext_ref = of_property_read_bool(spi->dev.of_node, 226 "REF-supply"); 227 } else { 228 struct ad7303_platform_data *pdata = spi->dev.platform_data; 229 if (pdata && pdata->use_external_ref) 230 ext_ref = true; 231 else 232 ext_ref = false; 233 } 234 235 if (ext_ref) { 236 st->vref_reg = devm_regulator_get(&spi->dev, "REF"); 237 if (IS_ERR(st->vref_reg)) { 238 ret = PTR_ERR(st->vref_reg); 239 goto err_disable_vdd_reg; 240 } 241 242 ret = regulator_enable(st->vref_reg); 243 if (ret) 244 goto err_disable_vdd_reg; 245 246 st->config |= AD7303_CFG_EXTERNAL_VREF; 247 } 248 249 indio_dev->dev.parent = &spi->dev; 250 indio_dev->name = id->name; 251 indio_dev->info = &ad7303_info; 252 indio_dev->modes = INDIO_DIRECT_MODE; 253 indio_dev->channels = ad7303_channels; 254 indio_dev->num_channels = ARRAY_SIZE(ad7303_channels); 255 256 ret = iio_device_register(indio_dev); 257 if (ret) 258 goto err_disable_vref_reg; 259 260 return 0; 261 262 err_disable_vref_reg: 263 if (st->vref_reg) 264 regulator_disable(st->vref_reg); 265 err_disable_vdd_reg: 266 regulator_disable(st->vdd_reg); 267 return ret; 268 } 269 270 static int ad7303_remove(struct spi_device *spi) 271 { 272 struct iio_dev *indio_dev = spi_get_drvdata(spi); 273 struct ad7303_state *st = iio_priv(indio_dev); 274 275 iio_device_unregister(indio_dev); 276 277 if (st->vref_reg) 278 regulator_disable(st->vref_reg); 279 regulator_disable(st->vdd_reg); 280 281 return 0; 282 } 283 284 static const struct of_device_id ad7303_spi_of_match[] = { 285 { .compatible = "adi,ad7303", }, 286 { /* sentinel */ }, 287 }; 288 MODULE_DEVICE_TABLE(of, ad7303_spi_of_match); 289 290 static const struct spi_device_id ad7303_spi_ids[] = { 291 { "ad7303", 0 }, 292 {} 293 }; 294 MODULE_DEVICE_TABLE(spi, ad7303_spi_ids); 295 296 static struct spi_driver ad7303_driver = { 297 .driver = { 298 .name = "ad7303", 299 .of_match_table = of_match_ptr(ad7303_spi_of_match), 300 }, 301 .probe = ad7303_probe, 302 .remove = ad7303_remove, 303 .id_table = ad7303_spi_ids, 304 }; 305 module_spi_driver(ad7303_driver); 306 307 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 308 MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver"); 309 MODULE_LICENSE("GPL v2"); 310