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/mod_devicetable.h> 17 #include <linux/module.h> 18 #include <linux/interrupt.h> 19 #include <linux/bitops.h> 20 21 #include <linux/iio/iio.h> 22 #include <linux/iio/sysfs.h> 23 #include <linux/iio/buffer.h> 24 #include <linux/iio/trigger_consumer.h> 25 #include <linux/iio/triggered_buffer.h> 26 27 #define AD7298_WRITE BIT(15) /* write to the control register */ 28 #define AD7298_REPEAT BIT(14) /* repeated conversion enable */ 29 #define AD7298_CH(x) BIT(13 - (x)) /* channel select */ 30 #define AD7298_TSENSE BIT(5) /* temperature conversion enable */ 31 #define AD7298_EXTREF BIT(2) /* external reference enable */ 32 #define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */ 33 #define AD7298_PDD BIT(0) /* partial power down enable */ 34 35 #define AD7298_MAX_CHAN 8 36 #define AD7298_INTREF_mV 2500 37 38 #define AD7298_CH_TEMP 9 39 40 struct ad7298_state { 41 struct spi_device *spi; 42 struct regulator *reg; 43 unsigned ext_ref; 44 struct spi_transfer ring_xfer[10]; 45 struct spi_transfer scan_single_xfer[3]; 46 struct spi_message ring_msg; 47 struct spi_message scan_single_msg; 48 /* 49 * DMA (thus cache coherency maintenance) requires the 50 * transfer buffers to live in their own cache lines. 51 */ 52 __be16 rx_buf[12] ____cacheline_aligned; 53 __be16 tx_buf[2]; 54 }; 55 56 #define AD7298_V_CHAN(index) \ 57 { \ 58 .type = IIO_VOLTAGE, \ 59 .indexed = 1, \ 60 .channel = index, \ 61 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 62 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 63 .address = index, \ 64 .scan_index = index, \ 65 .scan_type = { \ 66 .sign = 'u', \ 67 .realbits = 12, \ 68 .storagebits = 16, \ 69 .endianness = IIO_BE, \ 70 }, \ 71 } 72 73 static const struct iio_chan_spec ad7298_channels[] = { 74 { 75 .type = IIO_TEMP, 76 .indexed = 1, 77 .channel = 0, 78 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 79 BIT(IIO_CHAN_INFO_SCALE) | 80 BIT(IIO_CHAN_INFO_OFFSET), 81 .address = AD7298_CH_TEMP, 82 .scan_index = -1, 83 .scan_type = { 84 .sign = 's', 85 .realbits = 32, 86 .storagebits = 32, 87 }, 88 }, 89 AD7298_V_CHAN(0), 90 AD7298_V_CHAN(1), 91 AD7298_V_CHAN(2), 92 AD7298_V_CHAN(3), 93 AD7298_V_CHAN(4), 94 AD7298_V_CHAN(5), 95 AD7298_V_CHAN(6), 96 AD7298_V_CHAN(7), 97 IIO_CHAN_SOFT_TIMESTAMP(8), 98 }; 99 100 /* 101 * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask 102 */ 103 static int ad7298_update_scan_mode(struct iio_dev *indio_dev, 104 const unsigned long *active_scan_mask) 105 { 106 struct ad7298_state *st = iio_priv(indio_dev); 107 int i, m; 108 unsigned short command; 109 int scan_count; 110 111 /* Now compute overall size */ 112 scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength); 113 114 command = AD7298_WRITE | st->ext_ref; 115 116 for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1) 117 if (test_bit(i, active_scan_mask)) 118 command |= m; 119 120 st->tx_buf[0] = cpu_to_be16(command); 121 122 /* build spi ring message */ 123 st->ring_xfer[0].tx_buf = &st->tx_buf[0]; 124 st->ring_xfer[0].len = 2; 125 st->ring_xfer[0].cs_change = 1; 126 st->ring_xfer[1].tx_buf = &st->tx_buf[1]; 127 st->ring_xfer[1].len = 2; 128 st->ring_xfer[1].cs_change = 1; 129 130 spi_message_init(&st->ring_msg); 131 spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg); 132 spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg); 133 134 for (i = 0; i < scan_count; i++) { 135 st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i]; 136 st->ring_xfer[i + 2].len = 2; 137 st->ring_xfer[i + 2].cs_change = 1; 138 spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg); 139 } 140 /* make sure last transfer cs_change is not set */ 141 st->ring_xfer[i + 1].cs_change = 0; 142 143 return 0; 144 } 145 146 static irqreturn_t ad7298_trigger_handler(int irq, void *p) 147 { 148 struct iio_poll_func *pf = p; 149 struct iio_dev *indio_dev = pf->indio_dev; 150 struct ad7298_state *st = iio_priv(indio_dev); 151 int b_sent; 152 153 b_sent = spi_sync(st->spi, &st->ring_msg); 154 if (b_sent) 155 goto done; 156 157 iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, 158 iio_get_time_ns(indio_dev)); 159 160 done: 161 iio_trigger_notify_done(indio_dev->trig); 162 163 return IRQ_HANDLED; 164 } 165 166 static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch) 167 { 168 int ret; 169 st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref | 170 (AD7298_CH(0) >> ch)); 171 172 ret = spi_sync(st->spi, &st->scan_single_msg); 173 if (ret) 174 return ret; 175 176 return be16_to_cpu(st->rx_buf[0]); 177 } 178 179 static int ad7298_scan_temp(struct ad7298_state *st, int *val) 180 { 181 int ret; 182 __be16 buf; 183 184 buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE | 185 AD7298_TAVG | st->ext_ref); 186 187 ret = spi_write(st->spi, (u8 *)&buf, 2); 188 if (ret) 189 return ret; 190 191 buf = cpu_to_be16(0); 192 193 ret = spi_write(st->spi, (u8 *)&buf, 2); 194 if (ret) 195 return ret; 196 197 usleep_range(101, 1000); /* sleep > 100us */ 198 199 ret = spi_read(st->spi, (u8 *)&buf, 2); 200 if (ret) 201 return ret; 202 203 *val = sign_extend32(be16_to_cpu(buf), 11); 204 205 return 0; 206 } 207 208 static int ad7298_get_ref_voltage(struct ad7298_state *st) 209 { 210 int vref; 211 212 if (st->reg) { 213 vref = regulator_get_voltage(st->reg); 214 if (vref < 0) 215 return vref; 216 217 return vref / 1000; 218 } else { 219 return AD7298_INTREF_mV; 220 } 221 } 222 223 static int ad7298_read_raw(struct iio_dev *indio_dev, 224 struct iio_chan_spec const *chan, 225 int *val, 226 int *val2, 227 long m) 228 { 229 int ret; 230 struct ad7298_state *st = iio_priv(indio_dev); 231 232 switch (m) { 233 case IIO_CHAN_INFO_RAW: 234 ret = iio_device_claim_direct_mode(indio_dev); 235 if (ret) 236 return ret; 237 238 if (chan->address == AD7298_CH_TEMP) 239 ret = ad7298_scan_temp(st, val); 240 else 241 ret = ad7298_scan_direct(st, chan->address); 242 243 iio_device_release_direct_mode(indio_dev); 244 245 if (ret < 0) 246 return ret; 247 248 if (chan->address != AD7298_CH_TEMP) 249 *val = ret & GENMASK(chan->scan_type.realbits - 1, 0); 250 251 return IIO_VAL_INT; 252 case IIO_CHAN_INFO_SCALE: 253 switch (chan->type) { 254 case IIO_VOLTAGE: 255 *val = ad7298_get_ref_voltage(st); 256 *val2 = chan->scan_type.realbits; 257 return IIO_VAL_FRACTIONAL_LOG2; 258 case IIO_TEMP: 259 *val = ad7298_get_ref_voltage(st); 260 *val2 = 10; 261 return IIO_VAL_FRACTIONAL; 262 default: 263 return -EINVAL; 264 } 265 case IIO_CHAN_INFO_OFFSET: 266 *val = 1093 - 2732500 / ad7298_get_ref_voltage(st); 267 return IIO_VAL_INT; 268 } 269 return -EINVAL; 270 } 271 272 static const struct iio_info ad7298_info = { 273 .read_raw = &ad7298_read_raw, 274 .update_scan_mode = ad7298_update_scan_mode, 275 }; 276 277 static void ad7298_reg_disable(void *data) 278 { 279 struct regulator *reg = data; 280 281 regulator_disable(reg); 282 } 283 284 static int ad7298_probe(struct spi_device *spi) 285 { 286 struct ad7298_state *st; 287 struct iio_dev *indio_dev; 288 int ret; 289 290 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 291 if (indio_dev == NULL) 292 return -ENOMEM; 293 294 st = iio_priv(indio_dev); 295 296 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 297 if (!IS_ERR(st->reg)) { 298 st->ext_ref = AD7298_EXTREF; 299 } else { 300 ret = PTR_ERR(st->reg); 301 if (ret != -ENODEV) 302 return ret; 303 304 st->reg = NULL; 305 } 306 307 if (st->reg) { 308 ret = regulator_enable(st->reg); 309 if (ret) 310 return ret; 311 312 ret = devm_add_action_or_reset(&spi->dev, ad7298_reg_disable, 313 st->reg); 314 if (ret) 315 return ret; 316 } 317 318 st->spi = spi; 319 320 indio_dev->name = spi_get_device_id(spi)->name; 321 indio_dev->modes = INDIO_DIRECT_MODE; 322 indio_dev->channels = ad7298_channels; 323 indio_dev->num_channels = ARRAY_SIZE(ad7298_channels); 324 indio_dev->info = &ad7298_info; 325 326 /* Setup default message */ 327 328 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; 329 st->scan_single_xfer[0].len = 2; 330 st->scan_single_xfer[0].cs_change = 1; 331 st->scan_single_xfer[1].tx_buf = &st->tx_buf[1]; 332 st->scan_single_xfer[1].len = 2; 333 st->scan_single_xfer[1].cs_change = 1; 334 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; 335 st->scan_single_xfer[2].len = 2; 336 337 spi_message_init(&st->scan_single_msg); 338 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); 339 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); 340 spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg); 341 342 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, 343 &ad7298_trigger_handler, NULL); 344 if (ret) 345 return ret; 346 347 return devm_iio_device_register(&spi->dev, indio_dev); 348 } 349 350 static const struct acpi_device_id ad7298_acpi_ids[] = { 351 { "INT3494", 0 }, 352 { } 353 }; 354 MODULE_DEVICE_TABLE(acpi, ad7298_acpi_ids); 355 356 static const struct spi_device_id ad7298_id[] = { 357 {"ad7298", 0}, 358 {} 359 }; 360 MODULE_DEVICE_TABLE(spi, ad7298_id); 361 362 static struct spi_driver ad7298_driver = { 363 .driver = { 364 .name = "ad7298", 365 .acpi_match_table = ad7298_acpi_ids, 366 }, 367 .probe = ad7298_probe, 368 .id_table = ad7298_id, 369 }; 370 module_spi_driver(ad7298_driver); 371 372 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 373 MODULE_DESCRIPTION("Analog Devices AD7298 ADC"); 374 MODULE_LICENSE("GPL v2"); 375