1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * TI ADC108S102 SPI ADC driver 4 * 5 * Copyright (c) 2013-2015 Intel Corporation. 6 * Copyright (c) 2017 Siemens AG 7 * 8 * This IIO device driver is designed to work with the following 9 * analog to digital converters from Texas Instruments: 10 * ADC108S102 11 * ADC128S102 12 * The communication with ADC chip is via the SPI bus (mode 3). 13 */ 14 15 #include <linux/acpi.h> 16 #include <linux/iio/iio.h> 17 #include <linux/iio/buffer.h> 18 #include <linux/iio/types.h> 19 #include <linux/iio/triggered_buffer.h> 20 #include <linux/iio/trigger_consumer.h> 21 #include <linux/interrupt.h> 22 #include <linux/module.h> 23 #include <linux/property.h> 24 #include <linux/regulator/consumer.h> 25 #include <linux/spi/spi.h> 26 27 /* 28 * In case of ACPI, we use the hard-wired 5000 mV of the Galileo and IOT2000 29 * boards as default for the reference pin VA. Device tree users encode that 30 * via the vref-supply regulator. 31 */ 32 #define ADC108S102_VA_MV_ACPI_DEFAULT 5000 33 34 /* 35 * Defining the ADC resolution being 12 bits, we can use the same driver for 36 * both ADC108S102 (10 bits resolution) and ADC128S102 (12 bits resolution) 37 * chips. The ADC108S102 effectively returns a 12-bit result with the 2 38 * least-significant bits unset. 39 */ 40 #define ADC108S102_BITS 12 41 #define ADC108S102_MAX_CHANNELS 8 42 43 /* 44 * 16-bit SPI command format: 45 * [15:14] Ignored 46 * [13:11] 3-bit channel address 47 * [10:0] Ignored 48 */ 49 #define ADC108S102_CMD(ch) ((u16)(ch) << 11) 50 51 /* 52 * 16-bit SPI response format: 53 * [15:12] Zeros 54 * [11:0] 12-bit ADC sample (for ADC108S102, [1:0] will always be 0). 55 */ 56 #define ADC108S102_RES_DATA(res) ((u16)res & GENMASK(11, 0)) 57 58 struct adc108s102_state { 59 struct spi_device *spi; 60 struct regulator *reg; 61 u32 va_millivolt; 62 /* SPI transfer used by triggered buffer handler*/ 63 struct spi_transfer ring_xfer; 64 /* SPI transfer used by direct scan */ 65 struct spi_transfer scan_single_xfer; 66 /* SPI message used by ring_xfer SPI transfer */ 67 struct spi_message ring_msg; 68 /* SPI message used by scan_single_xfer SPI transfer */ 69 struct spi_message scan_single_msg; 70 71 /* 72 * SPI message buffers: 73 * tx_buf: |C0|C1|C2|C3|C4|C5|C6|C7|XX| 74 * rx_buf: |XX|R0|R1|R2|R3|R4|R5|R6|R7|tt|tt|tt|tt| 75 * 76 * tx_buf: 8 channel read commands, plus 1 dummy command 77 * rx_buf: 1 dummy response, 8 channel responses, plus 64-bit timestamp 78 */ 79 __be16 rx_buf[13] ____cacheline_aligned; 80 __be16 tx_buf[9] ____cacheline_aligned; 81 }; 82 83 #define ADC108S102_V_CHAN(index) \ 84 { \ 85 .type = IIO_VOLTAGE, \ 86 .indexed = 1, \ 87 .channel = index, \ 88 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ 89 BIT(IIO_CHAN_INFO_SCALE), \ 90 .address = index, \ 91 .scan_index = index, \ 92 .scan_type = { \ 93 .sign = 'u', \ 94 .realbits = ADC108S102_BITS, \ 95 .storagebits = 16, \ 96 .endianness = IIO_BE, \ 97 }, \ 98 } 99 100 static const struct iio_chan_spec adc108s102_channels[] = { 101 ADC108S102_V_CHAN(0), 102 ADC108S102_V_CHAN(1), 103 ADC108S102_V_CHAN(2), 104 ADC108S102_V_CHAN(3), 105 ADC108S102_V_CHAN(4), 106 ADC108S102_V_CHAN(5), 107 ADC108S102_V_CHAN(6), 108 ADC108S102_V_CHAN(7), 109 IIO_CHAN_SOFT_TIMESTAMP(8), 110 }; 111 112 static int adc108s102_update_scan_mode(struct iio_dev *indio_dev, 113 unsigned long const *active_scan_mask) 114 { 115 struct adc108s102_state *st = iio_priv(indio_dev); 116 unsigned int bit, cmds; 117 118 /* 119 * Fill in the first x shorts of tx_buf with the number of channels 120 * enabled for sampling by the triggered buffer. 121 */ 122 cmds = 0; 123 for_each_set_bit(bit, active_scan_mask, ADC108S102_MAX_CHANNELS) 124 st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit)); 125 126 /* One dummy command added, to clock in the last response */ 127 st->tx_buf[cmds++] = 0x00; 128 129 /* build SPI ring message */ 130 st->ring_xfer.tx_buf = &st->tx_buf[0]; 131 st->ring_xfer.rx_buf = &st->rx_buf[0]; 132 st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]); 133 134 spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1); 135 136 return 0; 137 } 138 139 static irqreturn_t adc108s102_trigger_handler(int irq, void *p) 140 { 141 struct iio_poll_func *pf = p; 142 struct iio_dev *indio_dev = pf->indio_dev; 143 struct adc108s102_state *st = iio_priv(indio_dev); 144 int ret; 145 146 ret = spi_sync(st->spi, &st->ring_msg); 147 if (ret < 0) 148 goto out_notify; 149 150 /* Skip the dummy response in the first slot */ 151 iio_push_to_buffers_with_timestamp(indio_dev, 152 (u8 *)&st->rx_buf[1], 153 iio_get_time_ns(indio_dev)); 154 155 out_notify: 156 iio_trigger_notify_done(indio_dev->trig); 157 158 return IRQ_HANDLED; 159 } 160 161 static int adc108s102_scan_direct(struct adc108s102_state *st, unsigned int ch) 162 { 163 int ret; 164 165 st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch)); 166 ret = spi_sync(st->spi, &st->scan_single_msg); 167 if (ret) 168 return ret; 169 170 /* Skip the dummy response in the first slot */ 171 return be16_to_cpu(st->rx_buf[1]); 172 } 173 174 static int adc108s102_read_raw(struct iio_dev *indio_dev, 175 struct iio_chan_spec const *chan, 176 int *val, int *val2, long m) 177 { 178 struct adc108s102_state *st = iio_priv(indio_dev); 179 int ret; 180 181 switch (m) { 182 case IIO_CHAN_INFO_RAW: 183 ret = iio_device_claim_direct_mode(indio_dev); 184 if (ret) 185 return ret; 186 187 ret = adc108s102_scan_direct(st, chan->address); 188 189 iio_device_release_direct_mode(indio_dev); 190 191 if (ret < 0) 192 return ret; 193 194 *val = ADC108S102_RES_DATA(ret); 195 196 return IIO_VAL_INT; 197 case IIO_CHAN_INFO_SCALE: 198 if (chan->type != IIO_VOLTAGE) 199 break; 200 201 *val = st->va_millivolt; 202 *val2 = chan->scan_type.realbits; 203 204 return IIO_VAL_FRACTIONAL_LOG2; 205 default: 206 break; 207 } 208 209 return -EINVAL; 210 } 211 212 static const struct iio_info adc108s102_info = { 213 .read_raw = &adc108s102_read_raw, 214 .update_scan_mode = &adc108s102_update_scan_mode, 215 }; 216 217 static int adc108s102_probe(struct spi_device *spi) 218 { 219 struct adc108s102_state *st; 220 struct iio_dev *indio_dev; 221 int ret; 222 223 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 224 if (!indio_dev) 225 return -ENOMEM; 226 227 st = iio_priv(indio_dev); 228 229 if (ACPI_COMPANION(&spi->dev)) { 230 st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT; 231 } else { 232 st->reg = devm_regulator_get(&spi->dev, "vref"); 233 if (IS_ERR(st->reg)) 234 return PTR_ERR(st->reg); 235 236 ret = regulator_enable(st->reg); 237 if (ret < 0) { 238 dev_err(&spi->dev, "Cannot enable vref regulator\n"); 239 return ret; 240 } 241 242 ret = regulator_get_voltage(st->reg); 243 if (ret < 0) { 244 dev_err(&spi->dev, "vref get voltage failed\n"); 245 return ret; 246 } 247 248 st->va_millivolt = ret / 1000; 249 } 250 251 spi_set_drvdata(spi, indio_dev); 252 st->spi = spi; 253 254 indio_dev->name = spi->modalias; 255 indio_dev->modes = INDIO_DIRECT_MODE; 256 indio_dev->channels = adc108s102_channels; 257 indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels); 258 indio_dev->info = &adc108s102_info; 259 260 /* Setup default message */ 261 st->scan_single_xfer.tx_buf = st->tx_buf; 262 st->scan_single_xfer.rx_buf = st->rx_buf; 263 st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]); 264 265 spi_message_init_with_transfers(&st->scan_single_msg, 266 &st->scan_single_xfer, 1); 267 268 ret = iio_triggered_buffer_setup(indio_dev, NULL, 269 &adc108s102_trigger_handler, NULL); 270 if (ret) 271 goto error_disable_reg; 272 273 ret = iio_device_register(indio_dev); 274 if (ret) { 275 dev_err(&spi->dev, "Failed to register IIO device\n"); 276 goto error_cleanup_triggered_buffer; 277 } 278 return 0; 279 280 error_cleanup_triggered_buffer: 281 iio_triggered_buffer_cleanup(indio_dev); 282 283 error_disable_reg: 284 regulator_disable(st->reg); 285 286 return ret; 287 } 288 289 static int adc108s102_remove(struct spi_device *spi) 290 { 291 struct iio_dev *indio_dev = spi_get_drvdata(spi); 292 struct adc108s102_state *st = iio_priv(indio_dev); 293 294 iio_device_unregister(indio_dev); 295 iio_triggered_buffer_cleanup(indio_dev); 296 297 regulator_disable(st->reg); 298 299 return 0; 300 } 301 302 #ifdef CONFIG_OF 303 static const struct of_device_id adc108s102_of_match[] = { 304 { .compatible = "ti,adc108s102" }, 305 { } 306 }; 307 MODULE_DEVICE_TABLE(of, adc108s102_of_match); 308 #endif 309 310 #ifdef CONFIG_ACPI 311 static const struct acpi_device_id adc108s102_acpi_ids[] = { 312 { "INT3495", 0 }, 313 { } 314 }; 315 MODULE_DEVICE_TABLE(acpi, adc108s102_acpi_ids); 316 #endif 317 318 static const struct spi_device_id adc108s102_id[] = { 319 { "adc108s102", 0 }, 320 { } 321 }; 322 MODULE_DEVICE_TABLE(spi, adc108s102_id); 323 324 static struct spi_driver adc108s102_driver = { 325 .driver = { 326 .name = "adc108s102", 327 .of_match_table = of_match_ptr(adc108s102_of_match), 328 .acpi_match_table = ACPI_PTR(adc108s102_acpi_ids), 329 }, 330 .probe = adc108s102_probe, 331 .remove = adc108s102_remove, 332 .id_table = adc108s102_id, 333 }; 334 module_spi_driver(adc108s102_driver); 335 336 MODULE_AUTHOR("Bogdan Pricop <bogdan.pricop@emutex.com>"); 337 MODULE_DESCRIPTION("Texas Instruments ADC108S102 and ADC128S102 driver"); 338 MODULE_LICENSE("GPL v2"); 339