1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AD7887 SPI ADC driver 4 * 5 * Copyright 2010-2011 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/module.h> 16 #include <linux/interrupt.h> 17 #include <linux/bitops.h> 18 19 #include <linux/iio/iio.h> 20 #include <linux/iio/sysfs.h> 21 #include <linux/iio/buffer.h> 22 23 #include <linux/iio/trigger_consumer.h> 24 #include <linux/iio/triggered_buffer.h> 25 26 #include <linux/platform_data/ad7887.h> 27 28 #define AD7887_REF_DIS BIT(5) /* on-chip reference disable */ 29 #define AD7887_DUAL BIT(4) /* dual-channel mode */ 30 #define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */ 31 #define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */ 32 #define AD7887_PM_MODE1 0 /* CS based shutdown */ 33 #define AD7887_PM_MODE2 1 /* full on */ 34 #define AD7887_PM_MODE3 2 /* auto shutdown after conversion */ 35 #define AD7887_PM_MODE4 3 /* standby mode */ 36 37 enum ad7887_channels { 38 AD7887_CH0, 39 AD7887_CH0_CH1, 40 AD7887_CH1, 41 }; 42 43 /** 44 * struct ad7887_chip_info - chip specific information 45 * @int_vref_mv: the internal reference voltage 46 * @channels: channels specification 47 * @num_channels: number of channels 48 * @dual_channels: channels specification in dual mode 49 * @num_dual_channels: number of channels in dual mode 50 */ 51 struct ad7887_chip_info { 52 u16 int_vref_mv; 53 const struct iio_chan_spec *channels; 54 unsigned int num_channels; 55 const struct iio_chan_spec *dual_channels; 56 unsigned int num_dual_channels; 57 }; 58 59 struct ad7887_state { 60 struct spi_device *spi; 61 const struct ad7887_chip_info *chip_info; 62 struct regulator *reg; 63 struct spi_transfer xfer[4]; 64 struct spi_message msg[3]; 65 struct spi_message *ring_msg; 66 unsigned char tx_cmd_buf[4]; 67 68 /* 69 * DMA (thus cache coherency maintenance) may require the 70 * transfer buffers to live in their own cache lines. 71 * Buffer needs to be large enough to hold two 16 bit samples and a 72 * 64 bit aligned 64 bit timestamp. 73 */ 74 unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN); 75 }; 76 77 enum ad7887_supported_device_ids { 78 ID_AD7887 79 }; 80 81 static int ad7887_ring_preenable(struct iio_dev *indio_dev) 82 { 83 struct ad7887_state *st = iio_priv(indio_dev); 84 85 /* We know this is a single long so can 'cheat' */ 86 switch (*indio_dev->active_scan_mask) { 87 case (1 << 0): 88 st->ring_msg = &st->msg[AD7887_CH0]; 89 break; 90 case (1 << 1): 91 st->ring_msg = &st->msg[AD7887_CH1]; 92 /* Dummy read: push CH1 setting down to hardware */ 93 spi_sync(st->spi, st->ring_msg); 94 break; 95 case ((1 << 1) | (1 << 0)): 96 st->ring_msg = &st->msg[AD7887_CH0_CH1]; 97 break; 98 } 99 100 return 0; 101 } 102 103 static int ad7887_ring_postdisable(struct iio_dev *indio_dev) 104 { 105 struct ad7887_state *st = iio_priv(indio_dev); 106 107 /* dummy read: restore default CH0 settin */ 108 return spi_sync(st->spi, &st->msg[AD7887_CH0]); 109 } 110 111 static irqreturn_t ad7887_trigger_handler(int irq, void *p) 112 { 113 struct iio_poll_func *pf = p; 114 struct iio_dev *indio_dev = pf->indio_dev; 115 struct ad7887_state *st = iio_priv(indio_dev); 116 int b_sent; 117 118 b_sent = spi_sync(st->spi, st->ring_msg); 119 if (b_sent) 120 goto done; 121 122 iio_push_to_buffers_with_timestamp(indio_dev, st->data, 123 iio_get_time_ns(indio_dev)); 124 done: 125 iio_trigger_notify_done(indio_dev->trig); 126 127 return IRQ_HANDLED; 128 } 129 130 static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = { 131 .preenable = &ad7887_ring_preenable, 132 .postdisable = &ad7887_ring_postdisable, 133 }; 134 135 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch) 136 { 137 int ret = spi_sync(st->spi, &st->msg[ch]); 138 if (ret) 139 return ret; 140 141 return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1]; 142 } 143 144 static int ad7887_read_raw(struct iio_dev *indio_dev, 145 struct iio_chan_spec const *chan, 146 int *val, 147 int *val2, 148 long m) 149 { 150 int ret; 151 struct ad7887_state *st = iio_priv(indio_dev); 152 153 switch (m) { 154 case IIO_CHAN_INFO_RAW: 155 if (!iio_device_claim_direct(indio_dev)) 156 return -EBUSY; 157 ret = ad7887_scan_direct(st, chan->address); 158 iio_device_release_direct(indio_dev); 159 160 if (ret < 0) 161 return ret; 162 *val = ret >> chan->scan_type.shift; 163 *val &= GENMASK(chan->scan_type.realbits - 1, 0); 164 return IIO_VAL_INT; 165 case IIO_CHAN_INFO_SCALE: 166 if (st->reg) { 167 *val = regulator_get_voltage(st->reg); 168 if (*val < 0) 169 return *val; 170 *val /= 1000; 171 } else { 172 *val = st->chip_info->int_vref_mv; 173 } 174 175 *val2 = chan->scan_type.realbits; 176 177 return IIO_VAL_FRACTIONAL_LOG2; 178 } 179 return -EINVAL; 180 } 181 182 #define AD7887_CHANNEL(x) { \ 183 .type = IIO_VOLTAGE, \ 184 .indexed = 1, \ 185 .channel = (x), \ 186 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 187 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 188 .address = (x), \ 189 .scan_index = (x), \ 190 .scan_type = { \ 191 .sign = 'u', \ 192 .realbits = 12, \ 193 .storagebits = 16, \ 194 .shift = 0, \ 195 .endianness = IIO_BE, \ 196 }, \ 197 } 198 199 static const struct iio_chan_spec ad7887_channels[] = { 200 AD7887_CHANNEL(0), 201 IIO_CHAN_SOFT_TIMESTAMP(1), 202 }; 203 204 static const struct iio_chan_spec ad7887_dual_channels[] = { 205 AD7887_CHANNEL(0), 206 AD7887_CHANNEL(1), 207 IIO_CHAN_SOFT_TIMESTAMP(2), 208 }; 209 210 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = { 211 /* 212 * More devices added in future 213 */ 214 [ID_AD7887] = { 215 .channels = ad7887_channels, 216 .num_channels = ARRAY_SIZE(ad7887_channels), 217 .dual_channels = ad7887_dual_channels, 218 .num_dual_channels = ARRAY_SIZE(ad7887_dual_channels), 219 .int_vref_mv = 2500, 220 }, 221 }; 222 223 static const struct iio_info ad7887_info = { 224 .read_raw = &ad7887_read_raw, 225 }; 226 227 static void ad7887_reg_disable(void *data) 228 { 229 struct regulator *reg = data; 230 231 regulator_disable(reg); 232 } 233 234 static int ad7887_probe(struct spi_device *spi) 235 { 236 const struct ad7887_platform_data *pdata = dev_get_platdata(&spi->dev); 237 struct ad7887_state *st; 238 struct iio_dev *indio_dev; 239 uint8_t mode; 240 int ret; 241 242 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 243 if (indio_dev == NULL) 244 return -ENOMEM; 245 246 st = iio_priv(indio_dev); 247 248 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 249 if (IS_ERR(st->reg)) { 250 if (PTR_ERR(st->reg) != -ENODEV) 251 return PTR_ERR(st->reg); 252 253 st->reg = NULL; 254 } 255 256 if (st->reg) { 257 ret = regulator_enable(st->reg); 258 if (ret) 259 return ret; 260 261 ret = devm_add_action_or_reset(&spi->dev, ad7887_reg_disable, st->reg); 262 if (ret) 263 return ret; 264 } 265 266 st->chip_info = 267 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data]; 268 269 st->spi = spi; 270 271 indio_dev->name = spi_get_device_id(spi)->name; 272 indio_dev->info = &ad7887_info; 273 indio_dev->modes = INDIO_DIRECT_MODE; 274 275 /* Setup default message */ 276 277 mode = AD7887_PM_MODE4; 278 if (!st->reg) 279 mode |= AD7887_REF_DIS; 280 if (pdata && pdata->en_dual) 281 mode |= AD7887_DUAL; 282 283 st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode; 284 285 st->xfer[0].rx_buf = &st->data[0]; 286 st->xfer[0].tx_buf = &st->tx_cmd_buf[0]; 287 st->xfer[0].len = 2; 288 289 spi_message_init(&st->msg[AD7887_CH0]); 290 spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]); 291 292 if (pdata && pdata->en_dual) { 293 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode; 294 295 st->xfer[1].rx_buf = &st->data[0]; 296 st->xfer[1].tx_buf = &st->tx_cmd_buf[2]; 297 st->xfer[1].len = 2; 298 299 st->xfer[2].rx_buf = &st->data[2]; 300 st->xfer[2].tx_buf = &st->tx_cmd_buf[0]; 301 st->xfer[2].len = 2; 302 303 spi_message_init(&st->msg[AD7887_CH0_CH1]); 304 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]); 305 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]); 306 307 st->xfer[3].rx_buf = &st->data[2]; 308 st->xfer[3].tx_buf = &st->tx_cmd_buf[2]; 309 st->xfer[3].len = 2; 310 311 spi_message_init(&st->msg[AD7887_CH1]); 312 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]); 313 314 indio_dev->channels = st->chip_info->dual_channels; 315 indio_dev->num_channels = st->chip_info->num_dual_channels; 316 } else { 317 indio_dev->channels = st->chip_info->channels; 318 indio_dev->num_channels = st->chip_info->num_channels; 319 } 320 321 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, 322 &iio_pollfunc_store_time, 323 &ad7887_trigger_handler, &ad7887_ring_setup_ops); 324 if (ret) 325 return ret; 326 327 return devm_iio_device_register(&spi->dev, indio_dev); 328 } 329 330 static const struct spi_device_id ad7887_id[] = { 331 { "ad7887", ID_AD7887 }, 332 { } 333 }; 334 MODULE_DEVICE_TABLE(spi, ad7887_id); 335 336 static struct spi_driver ad7887_driver = { 337 .driver = { 338 .name = "ad7887", 339 }, 340 .probe = ad7887_probe, 341 .id_table = ad7887_id, 342 }; 343 module_spi_driver(ad7887_driver); 344 345 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 346 MODULE_DESCRIPTION("Analog Devices AD7887 ADC"); 347 MODULE_LICENSE("GPL v2"); 348