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 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 78 */ 79 __be16 rx_buf[9] __aligned(IIO_DMA_MINALIGN); 80 __be16 tx_buf[9] __aligned(IIO_DMA_MINALIGN); 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_ts_unaligned(indio_dev, 152 &st->rx_buf[1], 153 st->ring_xfer.len - sizeof(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 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref"); 234 if (ret < 0) 235 return dev_err_probe(&spi->dev, ret, "failed get vref voltage\n"); 236 237 st->va_millivolt = ret / 1000; 238 } 239 240 st->spi = spi; 241 242 indio_dev->name = spi->modalias; 243 indio_dev->modes = INDIO_DIRECT_MODE; 244 indio_dev->channels = adc108s102_channels; 245 indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels); 246 indio_dev->info = &adc108s102_info; 247 248 /* Setup default message */ 249 st->scan_single_xfer.tx_buf = st->tx_buf; 250 st->scan_single_xfer.rx_buf = st->rx_buf; 251 st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]); 252 253 spi_message_init_with_transfers(&st->scan_single_msg, 254 &st->scan_single_xfer, 1); 255 256 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL, 257 &adc108s102_trigger_handler, 258 NULL); 259 if (ret) 260 return ret; 261 262 ret = devm_iio_device_register(&spi->dev, indio_dev); 263 if (ret) 264 dev_err(&spi->dev, "Failed to register IIO device\n"); 265 return ret; 266 } 267 268 static const struct of_device_id adc108s102_of_match[] = { 269 { .compatible = "ti,adc108s102" }, 270 { } 271 }; 272 MODULE_DEVICE_TABLE(of, adc108s102_of_match); 273 274 static const struct acpi_device_id adc108s102_acpi_ids[] = { 275 { "INT3495", 0 }, 276 { } 277 }; 278 MODULE_DEVICE_TABLE(acpi, adc108s102_acpi_ids); 279 280 static const struct spi_device_id adc108s102_id[] = { 281 { "adc108s102", 0 }, 282 { } 283 }; 284 MODULE_DEVICE_TABLE(spi, adc108s102_id); 285 286 static struct spi_driver adc108s102_driver = { 287 .driver = { 288 .name = "adc108s102", 289 .of_match_table = adc108s102_of_match, 290 .acpi_match_table = adc108s102_acpi_ids, 291 }, 292 .probe = adc108s102_probe, 293 .id_table = adc108s102_id, 294 }; 295 module_spi_driver(adc108s102_driver); 296 297 MODULE_AUTHOR("Bogdan Pricop <bogdan.pricop@emutex.com>"); 298 MODULE_DESCRIPTION("Texas Instruments ADC108S102 and ADC128S102 driver"); 299 MODULE_LICENSE("GPL v2"); 300