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 s64 time_ns = 0; 178 int b_sent; 179 180 b_sent = spi_sync(st->spi, &st->ring_msg); 181 if (b_sent) 182 goto done; 183 184 if (indio_dev->scan_timestamp) { 185 time_ns = iio_get_time_ns(); 186 memcpy((u8 *)st->rx_buf + indio_dev->scan_bytes - sizeof(s64), 187 &time_ns, sizeof(time_ns)); 188 } 189 190 iio_push_to_buffers(indio_dev, (u8 *)st->rx_buf); 191 192 done: 193 iio_trigger_notify_done(indio_dev->trig); 194 195 return IRQ_HANDLED; 196 } 197 198 static int ad7923_scan_direct(struct ad7923_state *st, unsigned ch) 199 { 200 int ret, cmd; 201 202 cmd = AD7923_WRITE_CR | AD7923_CHANNEL_WRITE(ch) | 203 AD7923_SEQUENCE_WRITE(AD7923_SEQUENCE_OFF) | 204 st->settings; 205 cmd <<= AD7923_SHIFT_REGISTER; 206 st->tx_buf[0] = cpu_to_be16(cmd); 207 208 ret = spi_sync(st->spi, &st->scan_single_msg); 209 if (ret) 210 return ret; 211 212 return be16_to_cpu(st->rx_buf[0]); 213 } 214 215 static int ad7923_get_range(struct ad7923_state *st) 216 { 217 int vref; 218 219 vref = regulator_get_voltage(st->reg); 220 if (vref < 0) 221 return vref; 222 223 vref /= 1000; 224 225 if (!(st->settings & AD7923_RANGE)) 226 vref *= 2; 227 228 return vref; 229 } 230 231 static int ad7923_read_raw(struct iio_dev *indio_dev, 232 struct iio_chan_spec const *chan, 233 int *val, 234 int *val2, 235 long m) 236 { 237 int ret; 238 struct ad7923_state *st = iio_priv(indio_dev); 239 240 switch (m) { 241 case IIO_CHAN_INFO_RAW: 242 mutex_lock(&indio_dev->mlock); 243 if (iio_buffer_enabled(indio_dev)) 244 ret = -EBUSY; 245 else 246 ret = ad7923_scan_direct(st, chan->address); 247 mutex_unlock(&indio_dev->mlock); 248 249 if (ret < 0) 250 return ret; 251 252 if (chan->address == EXTRACT(ret, 12, 4)) 253 *val = EXTRACT(ret, 0, 12); 254 else 255 return -EIO; 256 257 return IIO_VAL_INT; 258 case IIO_CHAN_INFO_SCALE: 259 ret = ad7923_get_range(st); 260 if (ret < 0) 261 return ret; 262 *val = ret; 263 *val2 = chan->scan_type.realbits; 264 return IIO_VAL_FRACTIONAL_LOG2; 265 } 266 return -EINVAL; 267 } 268 269 static const struct iio_info ad7923_info = { 270 .read_raw = &ad7923_read_raw, 271 .update_scan_mode = ad7923_update_scan_mode, 272 .driver_module = THIS_MODULE, 273 }; 274 275 static int ad7923_probe(struct spi_device *spi) 276 { 277 struct ad7923_state *st; 278 struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st)); 279 const struct ad7923_chip_info *info; 280 int ret; 281 282 if (indio_dev == NULL) 283 return -ENOMEM; 284 285 st = iio_priv(indio_dev); 286 287 spi_set_drvdata(spi, indio_dev); 288 289 st->spi = spi; 290 st->settings = AD7923_CODING | AD7923_RANGE | 291 AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS); 292 293 info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data]; 294 295 indio_dev->name = spi_get_device_id(spi)->name; 296 indio_dev->dev.parent = &spi->dev; 297 indio_dev->modes = INDIO_DIRECT_MODE; 298 indio_dev->channels = info->channels; 299 indio_dev->num_channels = info->num_channels; 300 indio_dev->info = &ad7923_info; 301 302 /* Setup default message */ 303 304 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0]; 305 st->scan_single_xfer[0].len = 2; 306 st->scan_single_xfer[0].cs_change = 1; 307 st->scan_single_xfer[1].rx_buf = &st->rx_buf[0]; 308 st->scan_single_xfer[1].len = 2; 309 310 spi_message_init(&st->scan_single_msg); 311 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg); 312 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg); 313 314 st->reg = regulator_get(&spi->dev, "refin"); 315 if (IS_ERR(st->reg)) { 316 ret = PTR_ERR(st->reg); 317 goto error_free; 318 } 319 ret = regulator_enable(st->reg); 320 if (ret) 321 goto error_put_reg; 322 323 ret = iio_triggered_buffer_setup(indio_dev, NULL, 324 &ad7923_trigger_handler, NULL); 325 if (ret) 326 goto error_disable_reg; 327 328 ret = iio_device_register(indio_dev); 329 if (ret) 330 goto error_cleanup_ring; 331 332 return 0; 333 334 error_cleanup_ring: 335 iio_triggered_buffer_cleanup(indio_dev); 336 error_disable_reg: 337 regulator_disable(st->reg); 338 error_put_reg: 339 regulator_put(st->reg); 340 error_free: 341 iio_device_free(indio_dev); 342 343 return ret; 344 } 345 346 static int ad7923_remove(struct spi_device *spi) 347 { 348 struct iio_dev *indio_dev = spi_get_drvdata(spi); 349 struct ad7923_state *st = iio_priv(indio_dev); 350 351 iio_device_unregister(indio_dev); 352 iio_triggered_buffer_cleanup(indio_dev); 353 regulator_disable(st->reg); 354 regulator_put(st->reg); 355 iio_device_free(indio_dev); 356 357 return 0; 358 } 359 360 static const struct spi_device_id ad7923_id[] = { 361 {"ad7904", AD7904}, 362 {"ad7914", AD7914}, 363 {"ad7923", AD7924}, 364 {"ad7924", AD7924}, 365 {} 366 }; 367 MODULE_DEVICE_TABLE(spi, ad7923_id); 368 369 static struct spi_driver ad7923_driver = { 370 .driver = { 371 .name = "ad7923", 372 .owner = THIS_MODULE, 373 }, 374 .probe = ad7923_probe, 375 .remove = ad7923_remove, 376 .id_table = ad7923_id, 377 }; 378 module_spi_driver(ad7923_driver); 379 380 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); 381 MODULE_AUTHOR("Patrick Vasseur <patrick.vasseur@c-s.fr>"); 382 MODULE_DESCRIPTION("Analog Devices AD7904/AD7914/AD7923/AD7924 ADC"); 383 MODULE_LICENSE("GPL v2"); 384