1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AD7298 SPI ADC driver 4 * 5 * Copyright 2011 Analog Devices Inc. 6 */ 7 8 #include <linux/device.h> 9 #include <linux/kernel.h> 10 #include <linux/slab.h> 11 #include <linux/sysfs.h> 12 #include <linux/spi/spi.h> 13 #include <linux/regulator/consumer.h> 14 #include <linux/err.h> 15 #include <linux/delay.h> 16 #include <linux/module.h> 17 #include <linux/interrupt.h> 18 #include <linux/bitops.h> 19 20 #include <linux/iio/iio.h> 21 #include <linux/iio/sysfs.h> 22 #include <linux/iio/buffer.h> 23 #include <linux/iio/trigger_consumer.h> 24 #include <linux/iio/triggered_buffer.h> 25 26 #include <linux/platform_data/ad7298.h> 27 28 #define AD7298_WRITE BIT(15) /* write to the control register */ 29 #define AD7298_REPEAT BIT(14) /* repeated conversion enable */ 30 #define AD7298_CH(x) BIT(13 - (x)) /* channel select */ 31 #define AD7298_TSENSE BIT(5) /* temperature conversion enable */ 32 #define AD7298_EXTREF BIT(2) /* external reference enable */ 33 #define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */ 34 #define AD7298_PDD BIT(0) /* partial power down enable */ 35 36 #define AD7298_MAX_CHAN 8 37 #define AD7298_INTREF_mV 2500 38 39 #define AD7298_CH_TEMP 9 40 41 struct ad7298_state { 42 struct spi_device *spi; 43 struct regulator *reg; 44 unsigned ext_ref; 45 struct spi_transfer ring_xfer[10]; 46 struct spi_transfer scan_single_xfer[3]; 47 struct spi_message ring_msg; 48 struct spi_message scan_single_msg; 49 /* 50 * DMA (thus cache coherency maintenance) requires the 51 * transfer buffers to live in their own cache lines. 52 */ 53 __be16 rx_buf[12] ____cacheline_aligned; 54 __be16 tx_buf[2]; 55 }; 56 57 #define AD7298_V_CHAN(index) \ 58 { \ 59 .type = IIO_VOLTAGE, \ 60 .indexed = 1, \ 61 .channel = index, \ 62 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 63 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 64 .address = index, \ 65 .scan_index = index, \ 66 .scan_type = { \ 67 .sign = 'u', \ 68 .realbits = 12, \ 69 .storagebits = 16, \ 70 .endianness = IIO_BE, \ 71 }, \ 72 } 73 74 static const struct iio_chan_spec ad7298_channels[] = { 75 { 76 .type = IIO_TEMP, 77 .indexed = 1, 78 .channel = 0, 79 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 80 BIT(IIO_CHAN_INFO_SCALE) | 81 BIT(IIO_CHAN_INFO_OFFSET), 82 .address = AD7298_CH_TEMP, 83 .scan_index = -1, 84 .scan_type = { 85 .sign = 's', 86 .realbits = 32, 87 .storagebits = 32, 88 }, 89 }, 90 AD7298_V_CHAN(0), 91 AD7298_V_CHAN(1), 92 AD7298_V_CHAN(2), 93 AD7298_V_CHAN(3), 94 AD7298_V_CHAN(4), 95 AD7298_V_CHAN(5), 96 AD7298_V_CHAN(6), 97 AD7298_V_CHAN(7), 98 IIO_CHAN_SOFT_TIMESTAMP(8), 99 }; 100 101 /** 102 * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask 103 **/ 104 static int ad7298_update_scan_mode(struct iio_dev *indio_dev, 105 const unsigned long *active_scan_mask) 106 { 107 struct ad7298_state *st = iio_priv(indio_dev); 108 int i, m; 109 unsigned short command; 110 int scan_count; 111 112 /* Now compute overall size */ 113 scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength); 114 115 command = AD7298_WRITE | st->ext_ref; 116 117 for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1) 118 if (test_bit(i, active_scan_mask)) 119 command |= m; 120 121 st->tx_buf[0] = cpu_to_be16(command); 122 123 /* build spi ring message */ 124 st->ring_xfer[0].tx_buf = &st->tx_buf[0]; 125 st->ring_xfer[0].len = 2; 126 st->ring_xfer[0].cs_change = 1; 127 st->ring_xfer[1].tx_buf = &st->tx_buf[1]; 128 st->ring_xfer[1].len = 2; 129 st->ring_xfer[1].cs_change = 1; 130 131 spi_message_init(&st->ring_msg); 132 spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg); 133 spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg); 134 135 for (i = 0; i < scan_count; i++) { 136 st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i]; 137 st->ring_xfer[i + 2].len = 2; 138 st->ring_xfer[i + 2].cs_change = 1; 139 spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg); 140 } 141 /* make sure last transfer cs_change is not set */ 142 st->ring_xfer[i + 1].cs_change = 0; 143 144 return 0; 145 } 146 147 /** 148 * ad7298_trigger_handler() bh of trigger launched polling to ring buffer 149 * 150 * Currently there is no option in this driver to disable the saving of 151 * timestamps within the ring. 152 **/ 153 static irqreturn_t ad7298_trigger_handler(int irq, void *p) 154 { 155 struct iio_poll_func *pf = p; 156 struct iio_dev *indio_dev = pf->indio_dev; 157 struct ad7298_state *st = iio_priv(indio_dev); 158 int b_sent; 159 160 b_sent = spi_sync(st->spi, &st->ring_msg); 161 if (b_sent) 162 goto done; 163 164 iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, 165 iio_get_time_ns(indio_dev)); 166 167 done: 168 iio_trigger_notify_done(indio_dev->trig); 169 170 return IRQ_HANDLED; 171 } 172 173 static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch) 174 { 175 int ret; 176 st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref | 177 (AD7298_CH(0) >> ch)); 178 179 ret = spi_sync(st->spi, &st->scan_single_msg); 180 if (ret) 181 return ret; 182 183 return be16_to_cpu(st->rx_buf[0]); 184 } 185 186 static int ad7298_scan_temp(struct ad7298_state *st, int *val) 187 { 188 int ret; 189 __be16 buf; 190 191 buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE | 192 AD7298_TAVG | st->ext_ref); 193 194 ret = spi_write(st->spi, (u8 *)&buf, 2); 195 if (ret) 196 return ret; 197 198 buf = cpu_to_be16(0); 199 200 ret = spi_write(st->spi, (u8 *)&buf, 2); 201 if (ret) 202 return ret; 203 204 usleep_range(101, 1000); /* sleep > 100us */ 205 206 ret = spi_read(st->spi, (u8 *)&buf, 2); 207 if (ret) 208 return ret; 209 210 *val = sign_extend32(be16_to_cpu(buf), 11); 211 212 return 0; 213 } 214 215 static int ad7298_get_ref_voltage(struct ad7298_state *st) 216 { 217 int vref; 218 219 if (st->ext_ref) { 220 vref = regulator_get_voltage(st->reg); 221 if (vref < 0) 222 return vref; 223 224 return vref / 1000; 225 } else { 226 return AD7298_INTREF_mV; 227 } 228 } 229 230 static int ad7298_read_raw(struct iio_dev *indio_dev, 231 struct iio_chan_spec const *chan, 232 int *val, 233 int *val2, 234 long m) 235 { 236 int ret; 237 struct ad7298_state *st = iio_priv(indio_dev); 238 239 switch (m) { 240 case IIO_CHAN_INFO_RAW: 241 ret = iio_device_claim_direct_mode(indio_dev); 242 if (ret) 243 return ret; 244 245 if (chan->address == AD7298_CH_TEMP) 246 ret = ad7298_scan_temp(st, val); 247 else 248 ret = ad7298_scan_direct(st, chan->address); 249 250 iio_device_release_direct_mode(indio_dev); 251 252 if (ret < 0) 253 return ret; 254 255 if (chan->address != AD7298_CH_TEMP) 256 *val = ret & GENMASK(chan->scan_type.realbits - 1, 0); 257 258 return IIO_VAL_INT; 259 case IIO_CHAN_INFO_SCALE: 260 switch (chan->type) { 261 case IIO_VOLTAGE: 262 *val = ad7298_get_ref_voltage(st); 263 *val2 = chan->scan_type.realbits; 264 return IIO_VAL_FRACTIONAL_LOG2; 265 case IIO_TEMP: 266 *val = ad7298_get_ref_voltage(st); 267 *val2 = 10; 268 return IIO_VAL_FRACTIONAL; 269 default: 270 return -EINVAL; 271 } 272 case IIO_CHAN_INFO_OFFSET: 273 *val = 1093 - 2732500 / ad7298_get_ref_voltage(st); 274 return IIO_VAL_INT; 275 } 276 return -EINVAL; 277 } 278 279 static const struct iio_info ad7298_info = { 280 .read_raw = &ad7298_read_raw, 281 .update_scan_mode = ad7298_update_scan_mode, 282 }; 283 284 static int ad7298_probe(struct spi_device *spi) 285 { 286 struct ad7298_platform_data *pdata = spi->dev.platform_data; 287 struct ad7298_state *st; 288 struct iio_dev *indio_dev; 289 int ret; 290 291 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 292 if (indio_dev == NULL) 293 return -ENOMEM; 294 295 st = iio_priv(indio_dev); 296 297 if (pdata && pdata->ext_ref) 298 st->ext_ref = AD7298_EXTREF; 299 300 if (st->ext_ref) { 301 st->reg = devm_regulator_get(&spi->dev, "vref"); 302 if (IS_ERR(st->reg)) 303 return PTR_ERR(st->reg); 304 305 ret = regulator_enable(st->reg); 306 if (ret) 307 return ret; 308 } 309 310 spi_set_drvdata(spi, indio_dev); 311 312 st->spi = spi; 313 314 indio_dev->name = spi_get_device_id(spi)->name; 315 indio_dev->dev.parent = &spi->dev; 316 indio_dev->dev.of_node = spi->dev.of_node; 317 indio_dev->modes = INDIO_DIRECT_MODE; 318 indio_dev->channels = ad7298_channels; 319 indio_dev->num_channels = ARRAY_SIZE(ad7298_channels); 320 indio_dev->info = &ad7298_info; 321 322 /* Setup default message */ 323 324 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; 325 st->scan_single_xfer[0].len = 2; 326 st->scan_single_xfer[0].cs_change = 1; 327 st->scan_single_xfer[1].tx_buf = &st->tx_buf[1]; 328 st->scan_single_xfer[1].len = 2; 329 st->scan_single_xfer[1].cs_change = 1; 330 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; 331 st->scan_single_xfer[2].len = 2; 332 333 spi_message_init(&st->scan_single_msg); 334 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); 335 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); 336 spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg); 337 338 ret = iio_triggered_buffer_setup(indio_dev, NULL, 339 &ad7298_trigger_handler, NULL); 340 if (ret) 341 goto error_disable_reg; 342 343 ret = iio_device_register(indio_dev); 344 if (ret) 345 goto error_cleanup_ring; 346 347 return 0; 348 349 error_cleanup_ring: 350 iio_triggered_buffer_cleanup(indio_dev); 351 error_disable_reg: 352 if (st->ext_ref) 353 regulator_disable(st->reg); 354 355 return ret; 356 } 357 358 static int ad7298_remove(struct spi_device *spi) 359 { 360 struct iio_dev *indio_dev = spi_get_drvdata(spi); 361 struct ad7298_state *st = iio_priv(indio_dev); 362 363 iio_device_unregister(indio_dev); 364 iio_triggered_buffer_cleanup(indio_dev); 365 if (st->ext_ref) 366 regulator_disable(st->reg); 367 368 return 0; 369 } 370 371 static const struct spi_device_id ad7298_id[] = { 372 {"ad7298", 0}, 373 {} 374 }; 375 MODULE_DEVICE_TABLE(spi, ad7298_id); 376 377 static struct spi_driver ad7298_driver = { 378 .driver = { 379 .name = "ad7298", 380 }, 381 .probe = ad7298_probe, 382 .remove = ad7298_remove, 383 .id_table = ad7298_id, 384 }; 385 module_spi_driver(ad7298_driver); 386 387 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 388 MODULE_DESCRIPTION("Analog Devices AD7298 ADC"); 389 MODULE_LICENSE("GPL v2"); 390