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