Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 442 insertions, 0 deletions

diff --git a/drivers/iio/adc/ad7949.c b/drivers/iio/adc/ad7949.c
new file mode 100644
index 000000000..edd0c3a35
--- /dev/null
+++ b/drivers/iio/adc/ad7949.c
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0
+/* ad7949.c - Analog Devices ADC driver 14/16 bits 4/8 channels
+ *
+ * Copyright (C) 2018 CMC NV
+ *
+ * https://www.analog.com/media/en/technical-documentation/data-sheets/AD7949.pdf
+ */
+
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/bitfield.h>
+
+#define AD7949_CFG_MASK_TOTAL		GENMASK(13, 0)
+
+/* CFG: Configuration Update */
+#define AD7949_CFG_MASK_OVERWRITE	BIT(13)
+
+/* INCC: Input Channel Configuration */
+#define AD7949_CFG_MASK_INCC		GENMASK(12, 10)
+#define AD7949_CFG_VAL_INCC_UNIPOLAR_GND	7
+#define AD7949_CFG_VAL_INCC_UNIPOLAR_COMM	6
+#define AD7949_CFG_VAL_INCC_UNIPOLAR_DIFF	4
+#define AD7949_CFG_VAL_INCC_TEMP		3
+#define AD7949_CFG_VAL_INCC_BIPOLAR		2
+#define AD7949_CFG_VAL_INCC_BIPOLAR_DIFF	0
+
+/* INX: Input channel Selection in a binary fashion */
+#define AD7949_CFG_MASK_INX		GENMASK(9, 7)
+
+/* BW: select bandwidth for low-pass filter. Full or Quarter */
+#define AD7949_CFG_MASK_BW_FULL		BIT(6)
+
+/* REF: reference/buffer selection */
+#define AD7949_CFG_MASK_REF		GENMASK(5, 3)
+#define AD7949_CFG_VAL_REF_EXT_TEMP_BUF		3
+#define AD7949_CFG_VAL_REF_EXT_TEMP		2
+#define AD7949_CFG_VAL_REF_INT_4096		1
+#define AD7949_CFG_VAL_REF_INT_2500		0
+#define AD7949_CFG_VAL_REF_EXTERNAL		BIT(1)
+
+/* SEQ: channel sequencer. Allows for scanning channels */
+#define AD7949_CFG_MASK_SEQ		GENMASK(2, 1)
+
+/* RB: Read back the CFG register */
+#define AD7949_CFG_MASK_RBN		BIT(0)
+
+enum {
+	ID_AD7949 = 0,
+	ID_AD7682,
+	ID_AD7689,
+};
+
+struct ad7949_adc_spec {
+	u8 num_channels;
+	u8 resolution;
+};
+
+static const struct ad7949_adc_spec ad7949_adc_spec[] = {
+	[ID_AD7949] = { .num_channels = 8, .resolution = 14 },
+	[ID_AD7682] = { .num_channels = 4, .resolution = 16 },
+	[ID_AD7689] = { .num_channels = 8, .resolution = 16 },
+};
+
+/**
+ * struct ad7949_adc_chip - AD ADC chip
+ * @lock: protects write sequences
+ * @vref: regulator generating Vref
+ * @indio_dev: reference to iio structure
+ * @spi: reference to spi structure
+ * @refsel: reference selection
+ * @resolution: resolution of the chip
+ * @cfg: copy of the configuration register
+ * @current_channel: current channel in use
+ * @buffer: buffer to send / receive data to / from device
+ * @buf8b: be16 buffer to exchange data with the device in 8-bit transfers
+ */
+struct ad7949_adc_chip {
+	struct mutex lock;
+	struct regulator *vref;
+	struct iio_dev *indio_dev;
+	struct spi_device *spi;
+	u32 refsel;
+	u8 resolution;
+	u16 cfg;
+	unsigned int current_channel;
+	u16 buffer __aligned(IIO_DMA_MINALIGN);
+	__be16 buf8b;
+};
+
+static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val,
+				u16 mask)
+{
+	int ret;
+
+	ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);
+
+	switch (ad7949_adc->spi->bits_per_word) {
+	case 16:
+		ad7949_adc->buffer = ad7949_adc->cfg << 2;
+		ret = spi_write(ad7949_adc->spi, &ad7949_adc->buffer, 2);
+		break;
+	case 14:
+		ad7949_adc->buffer = ad7949_adc->cfg;
+		ret = spi_write(ad7949_adc->spi, &ad7949_adc->buffer, 2);
+		break;
+	case 8:
+		/* Here, type is big endian as it must be sent in two transfers */
+		ad7949_adc->buf8b = cpu_to_be16(ad7949_adc->cfg << 2);
+		ret = spi_write(ad7949_adc->spi, &ad7949_adc->buf8b, 2);
+		break;
+	default:
+		dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * This delay is to avoid a new request before the required time to
+	 * send a new command to the device
+	 */
+	udelay(2);
+	return ret;
+}
+
+static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
+				   unsigned int channel)
+{
+	int ret;
+	int i;
+
+	/*
+	 * 1: write CFG for sample N and read old data (sample N-2)
+	 * 2: if CFG was not changed since sample N-1 then we'll get good data
+	 *    at the next xfer, so we bail out now, otherwise we write something
+	 *    and we read garbage (sample N-1 configuration).
+	 */
+	for (i = 0; i < 2; i++) {
+		ret = ad7949_spi_write_cfg(ad7949_adc,
+					   FIELD_PREP(AD7949_CFG_MASK_INX, channel),
+					   AD7949_CFG_MASK_INX);
+		if (ret)
+			return ret;
+		if (channel == ad7949_adc->current_channel)
+			break;
+	}
+
+	/* 3: write something and read actual data */
+	if (ad7949_adc->spi->bits_per_word == 8)
+		ret = spi_read(ad7949_adc->spi, &ad7949_adc->buf8b, 2);
+	else
+		ret = spi_read(ad7949_adc->spi, &ad7949_adc->buffer, 2);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * This delay is to avoid a new request before the required time to
+	 * send a new command to the device
+	 */
+	udelay(2);
+
+	ad7949_adc->current_channel = channel;
+
+	switch (ad7949_adc->spi->bits_per_word) {
+	case 16:
+		*val = ad7949_adc->buffer;
+		/* Shift-out padding bits */
+		*val >>= 16 - ad7949_adc->resolution;
+		break;
+	case 14:
+		*val = ad7949_adc->buffer & GENMASK(13, 0);
+		break;
+	case 8:
+		/* Here, type is big endian as data was sent in two transfers */
+		*val = be16_to_cpu(ad7949_adc->buf8b);
+		/* Shift-out padding bits */
+		*val >>= 16 - ad7949_adc->resolution;
+		break;
+	default:
+		dev_err(&ad7949_adc->indio_dev->dev, "unsupported BPW\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#define AD7949_ADC_CHANNEL(chan) {				\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.channel = (chan),					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+}
+
+static const struct iio_chan_spec ad7949_adc_channels[] = {
+	AD7949_ADC_CHANNEL(0),
+	AD7949_ADC_CHANNEL(1),
+	AD7949_ADC_CHANNEL(2),
+	AD7949_ADC_CHANNEL(3),
+	AD7949_ADC_CHANNEL(4),
+	AD7949_ADC_CHANNEL(5),
+	AD7949_ADC_CHANNEL(6),
+	AD7949_ADC_CHANNEL(7),
+};
+
+static int ad7949_spi_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev);
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&ad7949_adc->lock);
+		ret = ad7949_spi_read_channel(ad7949_adc, val, chan->channel);
+		mutex_unlock(&ad7949_adc->lock);
+
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+
+	case IIO_CHAN_INFO_SCALE:
+		switch (ad7949_adc->refsel) {
+		case AD7949_CFG_VAL_REF_INT_2500:
+			*val = 2500;
+			break;
+		case AD7949_CFG_VAL_REF_INT_4096:
+			*val = 4096;
+			break;
+		case AD7949_CFG_VAL_REF_EXT_TEMP:
+		case AD7949_CFG_VAL_REF_EXT_TEMP_BUF:
+			ret = regulator_get_voltage(ad7949_adc->vref);
+			if (ret < 0)
+				return ret;
+
+			/* convert value back to mV */
+			*val = ret / 1000;
+			break;
+		}
+
+		*val2 = (1 << ad7949_adc->resolution) - 1;
+		return IIO_VAL_FRACTIONAL;
+	}
+
+	return -EINVAL;
+}
+
+static int ad7949_spi_reg_access(struct iio_dev *indio_dev,
+			unsigned int reg, unsigned int writeval,
+			unsigned int *readval)
+{
+	struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev);
+	int ret = 0;
+
+	if (readval)
+		*readval = ad7949_adc->cfg;
+	else
+		ret = ad7949_spi_write_cfg(ad7949_adc, writeval,
+					   AD7949_CFG_MASK_TOTAL);
+
+	return ret;
+}
+
+static const struct iio_info ad7949_spi_info = {
+	.read_raw = ad7949_spi_read_raw,
+	.debugfs_reg_access = ad7949_spi_reg_access,
+};
+
+static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc)
+{
+	int ret;
+	int val;
+	u16 cfg;
+
+	ad7949_adc->current_channel = 0;
+
+	cfg = FIELD_PREP(AD7949_CFG_MASK_OVERWRITE, 1) |
+		FIELD_PREP(AD7949_CFG_MASK_INCC, AD7949_CFG_VAL_INCC_UNIPOLAR_GND) |
+		FIELD_PREP(AD7949_CFG_MASK_INX, ad7949_adc->current_channel) |
+		FIELD_PREP(AD7949_CFG_MASK_BW_FULL, 1) |
+		FIELD_PREP(AD7949_CFG_MASK_REF, ad7949_adc->refsel) |
+		FIELD_PREP(AD7949_CFG_MASK_SEQ, 0x0) |
+		FIELD_PREP(AD7949_CFG_MASK_RBN, 1);
+
+	ret = ad7949_spi_write_cfg(ad7949_adc, cfg, AD7949_CFG_MASK_TOTAL);
+
+	/*
+	 * Do two dummy conversions to apply the first configuration setting.
+	 * Required only after the start up of the device.
+	 */
+	ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);
+	ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);
+
+	return ret;
+}
+
+static void ad7949_disable_reg(void *reg)
+{
+	regulator_disable(reg);
+}
+
+static int ad7949_spi_probe(struct spi_device *spi)
+{
+	u32 spi_ctrl_mask = spi->controller->bits_per_word_mask;
+	struct device *dev = &spi->dev;
+	const struct ad7949_adc_spec *spec;
+	struct ad7949_adc_chip *ad7949_adc;
+	struct iio_dev *indio_dev;
+	u32 tmp;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc));
+	if (!indio_dev) {
+		dev_err(dev, "can not allocate iio device\n");
+		return -ENOMEM;
+	}
+
+	indio_dev->info = &ad7949_spi_info;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ad7949_adc_channels;
+	spi_set_drvdata(spi, indio_dev);
+
+	ad7949_adc = iio_priv(indio_dev);
+	ad7949_adc->indio_dev = indio_dev;
+	ad7949_adc->spi = spi;
+
+	spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data];
+	indio_dev->num_channels = spec->num_channels;
+	ad7949_adc->resolution = spec->resolution;
+
+	/* Set SPI bits per word */
+	if (spi_ctrl_mask & SPI_BPW_MASK(ad7949_adc->resolution)) {
+		spi->bits_per_word = ad7949_adc->resolution;
+	} else if (spi_ctrl_mask == SPI_BPW_MASK(16)) {
+		spi->bits_per_word = 16;
+	} else if (spi_ctrl_mask == SPI_BPW_MASK(8)) {
+		spi->bits_per_word = 8;
+	} else {
+		dev_err(dev, "unable to find common BPW with spi controller\n");
+		return -EINVAL;
+	}
+
+	/* Setup internal voltage reference */
+	tmp = 4096000;
+	device_property_read_u32(dev, "adi,internal-ref-microvolt", &tmp);
+
+	switch (tmp) {
+	case 2500000:
+		ad7949_adc->refsel = AD7949_CFG_VAL_REF_INT_2500;
+		break;
+	case 4096000:
+		ad7949_adc->refsel = AD7949_CFG_VAL_REF_INT_4096;
+		break;
+	default:
+		dev_err(dev, "unsupported internal voltage reference\n");
+		return -EINVAL;
+	}
+
+	/* Setup external voltage reference, buffered? */
+	ad7949_adc->vref = devm_regulator_get_optional(dev, "vrefin");
+	if (IS_ERR(ad7949_adc->vref)) {
+		ret = PTR_ERR(ad7949_adc->vref);
+		if (ret != -ENODEV)
+			return ret;
+		/* unbuffered? */
+		ad7949_adc->vref = devm_regulator_get_optional(dev, "vref");
+		if (IS_ERR(ad7949_adc->vref)) {
+			ret = PTR_ERR(ad7949_adc->vref);
+			if (ret != -ENODEV)
+				return ret;
+		} else {
+			ad7949_adc->refsel = AD7949_CFG_VAL_REF_EXT_TEMP;
+		}
+	} else {
+		ad7949_adc->refsel = AD7949_CFG_VAL_REF_EXT_TEMP_BUF;
+	}
+
+	if (ad7949_adc->refsel & AD7949_CFG_VAL_REF_EXTERNAL) {
+		ret = regulator_enable(ad7949_adc->vref);
+		if (ret < 0) {
+			dev_err(dev, "fail to enable regulator\n");
+			return ret;
+		}
+
+		ret = devm_add_action_or_reset(dev, ad7949_disable_reg,
+					       ad7949_adc->vref);
+		if (ret)
+			return ret;
+	}
+
+	mutex_init(&ad7949_adc->lock);
+
+	ret = ad7949_spi_init(ad7949_adc);
+	if (ret) {
+		dev_err(dev, "fail to init this device: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		dev_err(dev, "fail to register iio device: %d\n", ret);
+
+	return ret;
+}
+
+static const struct of_device_id ad7949_spi_of_id[] = {
+	{ .compatible = "adi,ad7949" },
+	{ .compatible = "adi,ad7682" },
+	{ .compatible = "adi,ad7689" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad7949_spi_of_id);
+
+static const struct spi_device_id ad7949_spi_id[] = {
+	{ "ad7949", ID_AD7949  },
+	{ "ad7682", ID_AD7682 },
+	{ "ad7689", ID_AD7689 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad7949_spi_id);
+
+static struct spi_driver ad7949_spi_driver = {
+	.driver = {
+		.name		= "ad7949",
+		.of_match_table	= ad7949_spi_of_id,
+	},
+	.probe	  = ad7949_spi_probe,
+	.id_table = ad7949_spi_id,
+};
+module_spi_driver(ad7949_spi_driver);
+
+MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
+MODULE_DESCRIPTION("Analog Devices 14/16-bit 8-channel ADC driver");
+MODULE_LICENSE("GPL v2");