1 /* 2 * AD7904/AD7914/AD7923/AD7924 SPI ADC driver 3 * 4 * Copyright 2011 Analog Devices Inc (from AD7923 Driver) 5 * Copyright 2012 CS Systemes d'Information 6 * 7 * Licensed under the GPL-2. 8 */ 9 10 #include <linux/device.h> 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/sysfs.h> 14 #include <linux/spi/spi.h> 15 #include <linux/regulator/consumer.h> 16 #include <linux/err.h> 17 #include <linux/delay.h> 18 #include <linux/module.h> 19 #include <linux/interrupt.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 AD7923_WRITE_CR (1 << 11) /* write control register */ 28 #define AD7923_RANGE (1 << 1) /* range to REFin */ 29 #define AD7923_CODING (1 << 0) /* coding is straight binary */ 30 #define AD7923_PM_MODE_AS (1) /* auto shutdown */ 31 #define AD7923_PM_MODE_FS (2) /* full shutdown */ 32 #define AD7923_PM_MODE_OPS (3) /* normal operation */ 33 #define AD7923_CHANNEL_0 (0) /* analog input 0 */ 34 #define AD7923_CHANNEL_1 (1) /* analog input 1 */ 35 #define AD7923_CHANNEL_2 (2) /* analog input 2 */ 36 #define AD7923_CHANNEL_3 (3) /* analog input 3 */ 37 #define AD7923_SEQUENCE_OFF (0) /* no sequence fonction */ 38 #define AD7923_SEQUENCE_PROTECT (2) /* no interrupt write cycle */ 39 #define AD7923_SEQUENCE_ON (3) /* continuous sequence */ 40 41 #define AD7923_MAX_CHAN 4 42 43 #define AD7923_PM_MODE_WRITE(mode) (mode << 4) /* write mode */ 44 #define AD7923_CHANNEL_WRITE(channel) (channel << 6) /* write channel */ 45 #define AD7923_SEQUENCE_WRITE(sequence) (((sequence & 1) << 3) \ 46 + ((sequence & 2) << 9)) 47 /* write sequence fonction */ 48 /* left shift for CR : bit 11 transmit in first */ 49 #define AD7923_SHIFT_REGISTER 4 50 51 /* val = value, dec = left shift, bits = number of bits of the mask */ 52 #define EXTRACT(val, dec, bits) ((val >> dec) & ((1 << bits) - 1)) 53 54 struct ad7923_state { 55 struct spi_device *spi; 56 struct spi_transfer ring_xfer[5]; 57 struct spi_transfer scan_single_xfer[2]; 58 struct spi_message ring_msg; 59 struct spi_message scan_single_msg; 60 61 struct regulator *reg; 62 63 unsigned int settings; 64 65 /* 66 * DMA (thus cache coherency maintenance) requires the 67 * transfer buffers to live in their own cache lines. 68 */ 69 __be16 rx_buf[4] ____cacheline_aligned; 70 __be16 tx_buf[4]; 71 }; 72 73 struct ad7923_chip_info { 74 const struct iio_chan_spec *channels; 75 unsigned int num_channels; 76 }; 77 78 enum ad7923_id { 79 AD7904, 80 AD7914, 81 AD7924, 82 }; 83 84 #define AD7923_V_CHAN(index, bits) \ 85 { \ 86 .type = IIO_VOLTAGE, \ 87 .indexed = 1, \ 88 .channel = index, \ 89 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 90 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 91 .address = index, \ 92 .scan_index = index, \ 93 .scan_type = { \ 94 .sign = 'u', \ 95 .realbits = (bits), \ 96 .storagebits = 16, \ 97 .endianness = IIO_BE, \ 98 }, \ 99 } 100 101 #define DECLARE_AD7923_CHANNELS(name, bits) \ 102 const struct iio_chan_spec name ## _channels[] = { \ 103 AD7923_V_CHAN(0, bits), \ 104 AD7923_V_CHAN(1, bits), \ 105 AD7923_V_CHAN(2, bits), \ 106 AD7923_V_CHAN(3, bits), \ 107 IIO_CHAN_SOFT_TIMESTAMP(4), \ 108 } 109 110 static DECLARE_AD7923_CHANNELS(ad7904, 8); 111 static DECLARE_AD7923_CHANNELS(ad7914, 10); 112 static DECLARE_AD7923_CHANNELS(ad7924, 12); 113 114 static const struct ad7923_chip_info ad7923_chip_info[] = { 115 [AD7904] = { 116 .channels = ad7904_channels, 117 .num_channels = ARRAY_SIZE(ad7904_channels), 118 }, 119 [AD7914] = { 120 .channels = ad7914_channels, 121 .num_channels = ARRAY_SIZE(ad7914_channels), 122 }, 123 [AD7924] = { 124 .channels = ad7924_channels, 125 .num_channels = ARRAY_SIZE(ad7924_channels), 126 }, 127 }; 128 129 /** 130 * ad7923_update_scan_mode() setup the spi transfer buffer for the new scan mask 131 **/ 132 static int ad7923_update_scan_mode(struct iio_dev *indio_dev, 133 const unsigned long *active_scan_mask) 134 { 135 struct ad7923_state *st = iio_priv(indio_dev); 136 int i, cmd, len; 137 138 len = 0; 139 for_each_set_bit(i, active_scan_mask, AD7923_MAX_CHAN) { 140 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(i) | 141 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) | 142 st->settings; 143 cmd <<= AD7923_SHIFT_REGISTER; 144 st->tx_buf[len++] = cpu_to_be16(cmd); 145 } 146 /* build spi ring message */ 147 st->ring_xfer[0].tx_buf = &st->tx_buf[0]; 148 st->ring_xfer[0].len = len; 149 st->ring_xfer[0].cs_change = 1; 150 151 spi_message_init(&st->ring_msg); 152 spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg); 153 154 for (i = 0; i < len; i++) { 155 st->ring_xfer[i + 1].rx_buf = &st->rx_buf[i]; 156 st->ring_xfer[i + 1].len = 2; 157 st->ring_xfer[i + 1].cs_change = 1; 158 spi_message_add_tail(&st->ring_xfer[i + 1], &st->ring_msg); 159 } 160 /* make sure last transfer cs_change is not set */ 161 st->ring_xfer[i + 1].cs_change = 0; 162 163 return 0; 164 } 165 166 /** 167 * ad7923_trigger_handler() bh of trigger launched polling to ring buffer 168 * 169 * Currently there is no option in this driver to disable the saving of 170 * timestamps within the ring. 171 **/ 172 static irqreturn_t ad7923_trigger_handler(int irq, void *p) 173 { 174 struct iio_poll_func *pf = p; 175 struct iio_dev *indio_dev = pf->indio_dev; 176 struct ad7923_state *st = iio_priv(indio_dev); 177 int b_sent; 178 179 b_sent = spi_sync(st->spi, &st->ring_msg); 180 if (b_sent) 181 goto done; 182 183 iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, 184 iio_get_time_ns()); 185 186 done: 187 iio_trigger_notify_done(indio_dev->trig); 188 189 return IRQ_HANDLED; 190 } 191 192 static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch) 193 { 194 int ret, cmd; 195 196 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) | 197 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) | 198 st->settings; 199 cmd <<= AD7923_SHIFT_REGISTER; 200 st->tx_buf[0] = cpu_to_be16(cmd); 201 202 ret = spi_sync(st->spi, &st->scan_single_msg); 203 if (ret) 204 return ret; 205 206 return be16_to_cpu(st->rx_buf[0]); 207 } 208 209 static int ad7923_get_range(struct ad7923_state *st) 210 { 211 int vref; 212 213 vref = regulator_get_voltage(st->reg); 214 if (vref < 0) 215 return vref; 216 217 vref /= 1000; 218 219 if (!(st->settings & AD7923_RANGE)) 220 vref *= 2; 221 222 return vref; 223 } 224 225 static int ad7923_read_raw(struct iio_dev *indio_dev, 226 struct iio_chan_spec const *chan, 227 int *val, 228 int *val2, 229 long m) 230 { 231 int ret; 232 struct ad7923_state *st = iio_priv(indio_dev); 233 234 switch (m) { 235 case IIO_CHAN_INFO_RAW: 236 mutex_lock(&indio_dev->mlock); 237 if (iio_buffer_enabled(indio_dev)) 238 ret = -EBUSY; 239 else 240 ret = ad7923_scan_direct(st, chan->address); 241 mutex_unlock(&indio_dev->mlock); 242 243 if (ret < 0) 244 return ret; 245 246 if (chan->address == EXTRACT(ret, 12, 4)) 247 *val = EXTRACT(ret, 0, 12); 248 else 249 return -EIO; 250 251 return IIO_VAL_INT; 252 case IIO_CHAN_INFO_SCALE: 253 ret = ad7923_get_range(st); 254 if (ret < 0) 255 return ret; 256 *val = ret; 257 *val2 = chan->scan_type.realbits; 258 return IIO_VAL_FRACTIONAL_LOG2; 259 } 260 return -EINVAL; 261 } 262 263 static const struct iio_info ad7923_info = { 264 .read_raw = &ad7923_read_raw, 265 .update_scan_mode = ad7923_update_scan_mode, 266 .driver_module = THIS_MODULE, 267 }; 268 269 static int ad7923_probe(struct spi_device *spi) 270 { 271 struct ad7923_state *st; 272 struct iio_dev *indio_dev; 273 const struct ad7923_chip_info *info; 274 int ret; 275 276 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 277 if (indio_dev == NULL) 278 return -ENOMEM; 279 280 st = iio_priv(indio_dev); 281 282 spi_set_drvdata(spi, indio_dev); 283 284 st->spi = spi; 285 st->settings = AD7923_CODING | AD7923_RANGE | 286 AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS); 287 288 info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data]; 289 290 indio_dev->name = spi_get_device_id(spi)->name; 291 indio_dev->dev.parent = &spi->dev; 292 indio_dev->modes = INDIO_DIRECT_MODE; 293 indio_dev->channels = info->channels; 294 indio_dev->num_channels = info->num_channels; 295 indio_dev->info = &ad7923_info; 296 297 /* Setup default message */ 298 299 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; 300 st->scan_single_xfer[0].len = 2; 301 st->scan_single_xfer[0].cs_change = 1; 302 st->scan_single_xfer[1].rx_buf = &st->rx_buf[0]; 303 st->scan_single_xfer[1].len = 2; 304 305 spi_message_init(&st->scan_single_msg); 306 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); 307 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); 308 309 st->reg = devm_regulator_get(&spi->dev, "refin"); 310 if (IS_ERR(st->reg)) 311 return PTR_ERR(st->reg); 312 313 ret = regulator_enable(st->reg); 314 if (ret) 315 return ret; 316 317 ret = iio_triggered_buffer_setup(indio_dev, NULL, 318 &ad7923_trigger_handler, NULL); 319 if (ret) 320 goto error_disable_reg; 321 322 ret = iio_device_register(indio_dev); 323 if (ret) 324 goto error_cleanup_ring; 325 326 return 0; 327 328 error_cleanup_ring: 329 iio_triggered_buffer_cleanup(indio_dev); 330 error_disable_reg: 331 regulator_disable(st->reg); 332 333 return ret; 334 } 335 336 static int ad7923_remove(struct spi_device *spi) 337 { 338 struct iio_dev *indio_dev = spi_get_drvdata(spi); 339 struct ad7923_state *st = iio_priv(indio_dev); 340 341 iio_device_unregister(indio_dev); 342 iio_triggered_buffer_cleanup(indio_dev); 343 regulator_disable(st->reg); 344 345 return 0; 346 } 347 348 static const struct spi_device_id ad7923_id[] = { 349 {"ad7904", AD7904}, 350 {"ad7914", AD7914}, 351 {"ad7923", AD7924}, 352 {"ad7924", AD7924}, 353 {} 354 }; 355 MODULE_DEVICE_TABLE(spi, ad7923_id); 356 357 static struct spi_driver ad7923_driver = { 358 .driver = { 359 .name = "ad7923", 360 }, 361 .probe = ad7923_probe, 362 .remove = ad7923_remove, 363 .id_table = ad7923_id, 364 }; 365 module_spi_driver(ad7923_driver); 366 367 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); 368 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>"); 369 MODULE_DESCRIPTION("Analog Devices AD7904/AD7914/AD7923/AD7924 ADC"); 370 MODULE_LICENSE("GPL v2"); 371