1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver 4 * 5 * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com> 6 * 7 * Datasheet: http://www.ti.com/lit/ds/symlink/adc0832-n.pdf 8 */ 9 10 #include <linux/module.h> 11 #include <linux/spi/spi.h> 12 #include <linux/iio/iio.h> 13 #include <linux/regulator/consumer.h> 14 #include <linux/iio/buffer.h> 15 #include <linux/iio/trigger.h> 16 #include <linux/iio/triggered_buffer.h> 17 #include <linux/iio/trigger_consumer.h> 18 19 enum { 20 adc0831, 21 adc0832, 22 adc0834, 23 adc0838, 24 }; 25 26 struct adc0832 { 27 struct spi_device *spi; 28 struct regulator *reg; 29 struct mutex lock; 30 u8 mux_bits; 31 32 u8 tx_buf[2] ____cacheline_aligned; 33 u8 rx_buf[2]; 34 }; 35 36 #define ADC0832_VOLTAGE_CHANNEL(chan) \ 37 { \ 38 .type = IIO_VOLTAGE, \ 39 .indexed = 1, \ 40 .channel = chan, \ 41 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 42 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 43 .scan_index = chan, \ 44 .scan_type = { \ 45 .sign = 'u', \ 46 .realbits = 8, \ 47 .storagebits = 8, \ 48 }, \ 49 } 50 51 #define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \ 52 { \ 53 .type = IIO_VOLTAGE, \ 54 .indexed = 1, \ 55 .channel = (chan1), \ 56 .channel2 = (chan2), \ 57 .differential = 1, \ 58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 60 .scan_index = si, \ 61 .scan_type = { \ 62 .sign = 'u', \ 63 .realbits = 8, \ 64 .storagebits = 8, \ 65 }, \ 66 } 67 68 static const struct iio_chan_spec adc0831_channels[] = { 69 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0), 70 IIO_CHAN_SOFT_TIMESTAMP(1), 71 }; 72 73 static const struct iio_chan_spec adc0832_channels[] = { 74 ADC0832_VOLTAGE_CHANNEL(0), 75 ADC0832_VOLTAGE_CHANNEL(1), 76 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2), 77 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3), 78 IIO_CHAN_SOFT_TIMESTAMP(4), 79 }; 80 81 static const struct iio_chan_spec adc0834_channels[] = { 82 ADC0832_VOLTAGE_CHANNEL(0), 83 ADC0832_VOLTAGE_CHANNEL(1), 84 ADC0832_VOLTAGE_CHANNEL(2), 85 ADC0832_VOLTAGE_CHANNEL(3), 86 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4), 87 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5), 88 ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6), 89 ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7), 90 IIO_CHAN_SOFT_TIMESTAMP(8), 91 }; 92 93 static const struct iio_chan_spec adc0838_channels[] = { 94 ADC0832_VOLTAGE_CHANNEL(0), 95 ADC0832_VOLTAGE_CHANNEL(1), 96 ADC0832_VOLTAGE_CHANNEL(2), 97 ADC0832_VOLTAGE_CHANNEL(3), 98 ADC0832_VOLTAGE_CHANNEL(4), 99 ADC0832_VOLTAGE_CHANNEL(5), 100 ADC0832_VOLTAGE_CHANNEL(6), 101 ADC0832_VOLTAGE_CHANNEL(7), 102 ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8), 103 ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9), 104 ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10), 105 ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11), 106 ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12), 107 ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13), 108 ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14), 109 ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15), 110 IIO_CHAN_SOFT_TIMESTAMP(16), 111 }; 112 113 static int adc0831_adc_conversion(struct adc0832 *adc) 114 { 115 struct spi_device *spi = adc->spi; 116 int ret; 117 118 ret = spi_read(spi, &adc->rx_buf, 2); 119 if (ret) 120 return ret; 121 122 /* 123 * Skip TRI-STATE and a leading zero 124 */ 125 return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6); 126 } 127 128 static int adc0832_adc_conversion(struct adc0832 *adc, int channel, 129 bool differential) 130 { 131 struct spi_device *spi = adc->spi; 132 struct spi_transfer xfer = { 133 .tx_buf = adc->tx_buf, 134 .rx_buf = adc->rx_buf, 135 .len = 2, 136 }; 137 int ret; 138 139 if (!adc->mux_bits) 140 return adc0831_adc_conversion(adc); 141 142 /* start bit */ 143 adc->tx_buf[0] = 1 << (adc->mux_bits + 1); 144 /* single-ended or differential */ 145 adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits); 146 /* odd / sign */ 147 adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1); 148 /* select */ 149 if (adc->mux_bits > 1) 150 adc->tx_buf[0] |= channel / 2; 151 152 /* align Data output BIT7 (MSB) to 8-bit boundary */ 153 adc->tx_buf[0] <<= 1; 154 155 ret = spi_sync_transfer(spi, &xfer, 1); 156 if (ret) 157 return ret; 158 159 return adc->rx_buf[1]; 160 } 161 162 static int adc0832_read_raw(struct iio_dev *iio, 163 struct iio_chan_spec const *channel, int *value, 164 int *shift, long mask) 165 { 166 struct adc0832 *adc = iio_priv(iio); 167 168 switch (mask) { 169 case IIO_CHAN_INFO_RAW: 170 mutex_lock(&adc->lock); 171 *value = adc0832_adc_conversion(adc, channel->channel, 172 channel->differential); 173 mutex_unlock(&adc->lock); 174 if (*value < 0) 175 return *value; 176 177 return IIO_VAL_INT; 178 case IIO_CHAN_INFO_SCALE: 179 *value = regulator_get_voltage(adc->reg); 180 if (*value < 0) 181 return *value; 182 183 /* convert regulator output voltage to mV */ 184 *value /= 1000; 185 *shift = 8; 186 187 return IIO_VAL_FRACTIONAL_LOG2; 188 } 189 190 return -EINVAL; 191 } 192 193 static const struct iio_info adc0832_info = { 194 .read_raw = adc0832_read_raw, 195 }; 196 197 static irqreturn_t adc0832_trigger_handler(int irq, void *p) 198 { 199 struct iio_poll_func *pf = p; 200 struct iio_dev *indio_dev = pf->indio_dev; 201 struct adc0832 *adc = iio_priv(indio_dev); 202 u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */ 203 int scan_index; 204 int i = 0; 205 206 mutex_lock(&adc->lock); 207 208 for_each_set_bit(scan_index, indio_dev->active_scan_mask, 209 indio_dev->masklength) { 210 const struct iio_chan_spec *scan_chan = 211 &indio_dev->channels[scan_index]; 212 int ret = adc0832_adc_conversion(adc, scan_chan->channel, 213 scan_chan->differential); 214 if (ret < 0) { 215 dev_warn(&adc->spi->dev, 216 "failed to get conversion data\n"); 217 goto out; 218 } 219 220 data[i] = ret; 221 i++; 222 } 223 iio_push_to_buffers_with_timestamp(indio_dev, data, 224 iio_get_time_ns(indio_dev)); 225 out: 226 mutex_unlock(&adc->lock); 227 228 iio_trigger_notify_done(indio_dev->trig); 229 230 return IRQ_HANDLED; 231 } 232 233 static int adc0832_probe(struct spi_device *spi) 234 { 235 struct iio_dev *indio_dev; 236 struct adc0832 *adc; 237 int ret; 238 239 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); 240 if (!indio_dev) 241 return -ENOMEM; 242 243 adc = iio_priv(indio_dev); 244 adc->spi = spi; 245 mutex_init(&adc->lock); 246 247 indio_dev->name = spi_get_device_id(spi)->name; 248 indio_dev->dev.parent = &spi->dev; 249 indio_dev->dev.of_node = spi->dev.of_node; 250 indio_dev->info = &adc0832_info; 251 indio_dev->modes = INDIO_DIRECT_MODE; 252 253 switch (spi_get_device_id(spi)->driver_data) { 254 case adc0831: 255 adc->mux_bits = 0; 256 indio_dev->channels = adc0831_channels; 257 indio_dev->num_channels = ARRAY_SIZE(adc0831_channels); 258 break; 259 case adc0832: 260 adc->mux_bits = 1; 261 indio_dev->channels = adc0832_channels; 262 indio_dev->num_channels = ARRAY_SIZE(adc0832_channels); 263 break; 264 case adc0834: 265 adc->mux_bits = 2; 266 indio_dev->channels = adc0834_channels; 267 indio_dev->num_channels = ARRAY_SIZE(adc0834_channels); 268 break; 269 case adc0838: 270 adc->mux_bits = 3; 271 indio_dev->channels = adc0838_channels; 272 indio_dev->num_channels = ARRAY_SIZE(adc0838_channels); 273 break; 274 default: 275 return -EINVAL; 276 } 277 278 adc->reg = devm_regulator_get(&spi->dev, "vref"); 279 if (IS_ERR(adc->reg)) 280 return PTR_ERR(adc->reg); 281 282 ret = regulator_enable(adc->reg); 283 if (ret) 284 return ret; 285 286 spi_set_drvdata(spi, indio_dev); 287 288 ret = iio_triggered_buffer_setup(indio_dev, NULL, 289 adc0832_trigger_handler, NULL); 290 if (ret) 291 goto err_reg_disable; 292 293 ret = iio_device_register(indio_dev); 294 if (ret) 295 goto err_buffer_cleanup; 296 297 return 0; 298 err_buffer_cleanup: 299 iio_triggered_buffer_cleanup(indio_dev); 300 err_reg_disable: 301 regulator_disable(adc->reg); 302 303 return ret; 304 } 305 306 static int adc0832_remove(struct spi_device *spi) 307 { 308 struct iio_dev *indio_dev = spi_get_drvdata(spi); 309 struct adc0832 *adc = iio_priv(indio_dev); 310 311 iio_device_unregister(indio_dev); 312 iio_triggered_buffer_cleanup(indio_dev); 313 regulator_disable(adc->reg); 314 315 return 0; 316 } 317 318 #ifdef CONFIG_OF 319 320 static const struct of_device_id adc0832_dt_ids[] = { 321 { .compatible = "ti,adc0831", }, 322 { .compatible = "ti,adc0832", }, 323 { .compatible = "ti,adc0834", }, 324 { .compatible = "ti,adc0838", }, 325 {} 326 }; 327 MODULE_DEVICE_TABLE(of, adc0832_dt_ids); 328 329 #endif 330 331 static const struct spi_device_id adc0832_id[] = { 332 { "adc0831", adc0831 }, 333 { "adc0832", adc0832 }, 334 { "adc0834", adc0834 }, 335 { "adc0838", adc0838 }, 336 {} 337 }; 338 MODULE_DEVICE_TABLE(spi, adc0832_id); 339 340 static struct spi_driver adc0832_driver = { 341 .driver = { 342 .name = "adc0832", 343 .of_match_table = of_match_ptr(adc0832_dt_ids), 344 }, 345 .probe = adc0832_probe, 346 .remove = adc0832_remove, 347 .id_table = adc0832_id, 348 }; 349 module_spi_driver(adc0832_driver); 350 351 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); 352 MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver"); 353 MODULE_LICENSE("GPL v2"); 354