1 // SPDX-License-Identifier: GPL-2.0-only
3  * TI ADC108S102 SPI ADC driver
5  * Copyright (c) 2013-2015 Intel Corporation.
12  * The communication with ADC chip is via the SPI bus (mode 3).
29  * In case of ACPI, we use the hard-wired 5000 mV of the Galileo and IOT2000
31  * via the vref-supply regulator.
36  * Defining the ADC resolution being 12 bits, we can use the same driver for
38  * chips. The ADC108S102 effectively returns a 12-bit result with the 2
39  * least-significant bits unset.
45  * 16-bit SPI command format:
47  *   [13:11] 3-bit channel address
53  * 16-bit SPI response format:
55  *   [11:0]  12-bit ADC sample (for ADC108S102, [1:0] will always be 0).
57 #define ADC108S102_RES_DATA(res)	((u16)res & GENMASK(11, 0))  argument
124 		st->tx_buf[cmds++] = cpu_to_be16(ADC108S102_CMD(bit));  in adc108s102_update_scan_mode()
127 	st->tx_buf[cmds++] = 0x00;  in adc108s102_update_scan_mode()
130 	st->ring_xfer.tx_buf = &st->tx_buf[0];  in adc108s102_update_scan_mode()
131 	st->ring_xfer.rx_buf = &st->rx_buf[0];  in adc108s102_update_scan_mode()
132 	st->ring_xfer.len = cmds * sizeof(st->tx_buf[0]);  in adc108s102_update_scan_mode()
134 	spi_message_init_with_transfers(&st->ring_msg, &st->ring_xfer, 1);  in adc108s102_update_scan_mode()
142 	struct iio_dev *indio_dev = pf->indio_dev;  in adc108s102_trigger_handler()
146 	ret = spi_sync(st->spi, &st->ring_msg);  in adc108s102_trigger_handler()
152 					      &st->rx_buf[1],  in adc108s102_trigger_handler()
153 					      st->ring_xfer.len - sizeof(st->rx_buf[1]),  in adc108s102_trigger_handler()
157 	iio_trigger_notify_done(indio_dev->trig);  in adc108s102_trigger_handler()
166 	st->tx_buf[0] = cpu_to_be16(ADC108S102_CMD(ch));  in adc108s102_scan_direct()
167 	ret = spi_sync(st->spi, &st->scan_single_msg);  in adc108s102_scan_direct()
172 	return be16_to_cpu(st->rx_buf[1]);  in adc108s102_scan_direct()
188 		ret = adc108s102_scan_direct(st, chan->address);  in adc108s102_read_raw()
199 		if (chan->type != IIO_VOLTAGE)  in adc108s102_read_raw()
202 		*val = st->va_millivolt;  in adc108s102_read_raw()
203 		*val2 = chan->scan_type.realbits;  in adc108s102_read_raw()
210 	return -EINVAL;  in adc108s102_read_raw()
224 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));  in adc108s102_probe()
226 		return -ENOMEM;  in adc108s102_probe()
230 	if (ACPI_COMPANION(&spi->dev)) {  in adc108s102_probe()
231 		st->va_millivolt = ADC108S102_VA_MV_ACPI_DEFAULT;  in adc108s102_probe()
233 		ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");  in adc108s102_probe()
235 			return dev_err_probe(&spi->dev, ret, "failed get vref voltage\n");  in adc108s102_probe()
237 		st->va_millivolt = ret / 1000;  in adc108s102_probe()
240 	st->spi = spi;  in adc108s102_probe()
242 	indio_dev->name = spi->modalias;  in adc108s102_probe()
243 	indio_dev->modes = INDIO_DIRECT_MODE;  in adc108s102_probe()
244 	indio_dev->channels = adc108s102_channels;  in adc108s102_probe()
245 	indio_dev->num_channels = ARRAY_SIZE(adc108s102_channels);  in adc108s102_probe()
246 	indio_dev->info = &adc108s102_info;  in adc108s102_probe()
249 	st->scan_single_xfer.tx_buf = st->tx_buf;  in adc108s102_probe()
250 	st->scan_single_xfer.rx_buf = st->rx_buf;  in adc108s102_probe()
251 	st->scan_single_xfer.len = 2 * sizeof(st->tx_buf[0]);  in adc108s102_probe()
253 	spi_message_init_with_transfers(&st->scan_single_msg,  in adc108s102_probe()
254 					&st->scan_single_xfer, 1);  in adc108s102_probe()
256 	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,  in adc108s102_probe()
262 	ret = devm_iio_device_register(&spi->dev, indio_dev);  in adc108s102_probe()
264 		dev_err(&spi->dev, "Failed to register IIO device\n");  in adc108s102_probe()