Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 912 insertions, 0 deletions

diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
new file mode 100644
index 000000000..1bbb51a66
--- /dev/null
+++ b/drivers/iio/adc/ti-tsc2046.c
@@ -0,0 +1,912 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Texas Instruments TSC2046 SPI ADC driver
+ *
+ * Copyright (c) 2021 Oleksij Rempel <kernel@pengutronix.de>, Pengutronix
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/units.h>
+
+#include <asm/unaligned.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger.h>
+
+/*
+ * The PENIRQ of TSC2046 controller is implemented as level shifter attached to
+ * the X+ line. If voltage of the X+ line reaches a specific level the IRQ will
+ * be activated or deactivated.
+ * To make this kind of IRQ reusable as trigger following additions were
+ * implemented:
+ * - rate limiting:
+ *   For typical touchscreen use case, we need to trigger about each 10ms.
+ * - hrtimer:
+ *   Continue triggering at least once after the IRQ was deactivated. Then
+ *   deactivate this trigger to stop sampling in order to reduce power
+ *   consumption.
+ */
+
+#define TI_TSC2046_NAME				"tsc2046"
+
+/* This driver doesn't aim at the peak continuous sample rate */
+#define	TI_TSC2046_MAX_SAMPLE_RATE		125000
+#define	TI_TSC2046_SAMPLE_BITS \
+	BITS_PER_TYPE(struct tsc2046_adc_atom)
+#define	TI_TSC2046_MAX_CLK_FREQ \
+	(TI_TSC2046_MAX_SAMPLE_RATE * TI_TSC2046_SAMPLE_BITS)
+
+#define TI_TSC2046_SAMPLE_INTERVAL_US		10000
+
+#define TI_TSC2046_START			BIT(7)
+#define TI_TSC2046_ADDR				GENMASK(6, 4)
+#define TI_TSC2046_ADDR_TEMP1			7
+#define TI_TSC2046_ADDR_AUX			6
+#define TI_TSC2046_ADDR_X			5
+#define TI_TSC2046_ADDR_Z2			4
+#define TI_TSC2046_ADDR_Z1			3
+#define TI_TSC2046_ADDR_VBAT			2
+#define TI_TSC2046_ADDR_Y			1
+#define TI_TSC2046_ADDR_TEMP0			0
+
+/*
+ * The mode bit sets the resolution of the ADC. With this bit low, the next
+ * conversion has 12-bit resolution, whereas with this bit high, the next
+ * conversion has 8-bit resolution. This driver is optimized for 12-bit mode.
+ * So, for this driver, this bit should stay zero.
+ */
+#define TI_TSC2046_8BIT_MODE			BIT(3)
+
+/*
+ * SER/DFR - The SER/DFR bit controls the reference mode, either single-ended
+ * (high) or differential (low).
+ */
+#define TI_TSC2046_SER				BIT(2)
+
+/*
+ * If VREF_ON and ADC_ON are both zero, then the chip operates in
+ * auto-wake/suspend mode. In most case this bits should stay zero.
+ */
+#define TI_TSC2046_PD1_VREF_ON			BIT(1)
+#define TI_TSC2046_PD0_ADC_ON			BIT(0)
+
+/*
+ * All supported devices can do 8 or 12bit resolution. This driver
+ * supports only 12bit mode, here we have a 16bit data transfer, where
+ * the MSB and the 3 LSB are 0.
+ */
+#define TI_TSC2046_DATA_12BIT			GENMASK(14, 3)
+
+#define TI_TSC2046_MAX_CHAN			8
+#define TI_TSC2046_MIN_POLL_CNT			3
+#define TI_TSC2046_EXT_POLL_CNT			3
+#define TI_TSC2046_POLL_CNT \
+	(TI_TSC2046_MIN_POLL_CNT + TI_TSC2046_EXT_POLL_CNT)
+#define TI_TSC2046_INT_VREF			2500
+
+/* Represents a HW sample */
+struct tsc2046_adc_atom {
+	/*
+	 * Command transmitted to the controller. This field is empty on the RX
+	 * buffer.
+	 */
+	u8 cmd;
+	/*
+	 * Data received from the controller. This field is empty for the TX
+	 * buffer
+	 */
+	__be16 data;
+} __packed;
+
+/* Layout of atomic buffers within big buffer */
+struct tsc2046_adc_group_layout {
+	/* Group offset within the SPI RX buffer */
+	unsigned int offset;
+	/*
+	 * Amount of tsc2046_adc_atom structs within the same command gathered
+	 * within same group.
+	 */
+	unsigned int count;
+	/*
+	 * Settling samples (tsc2046_adc_atom structs) which should be skipped
+	 * before good samples will start.
+	 */
+	unsigned int skip;
+};
+
+struct tsc2046_adc_dcfg {
+	const struct iio_chan_spec *channels;
+	unsigned int num_channels;
+};
+
+struct tsc2046_adc_ch_cfg {
+	unsigned int settling_time_us;
+	unsigned int oversampling_ratio;
+};
+
+enum tsc2046_state {
+	TSC2046_STATE_SHUTDOWN,
+	TSC2046_STATE_STANDBY,
+	TSC2046_STATE_POLL,
+	TSC2046_STATE_POLL_IRQ_DISABLE,
+	TSC2046_STATE_ENABLE_IRQ,
+};
+
+struct tsc2046_adc_priv {
+	struct spi_device *spi;
+	const struct tsc2046_adc_dcfg *dcfg;
+	struct regulator *vref_reg;
+
+	struct iio_trigger *trig;
+	struct hrtimer trig_timer;
+	enum tsc2046_state state;
+	int poll_cnt;
+	spinlock_t state_lock;
+
+	struct spi_transfer xfer;
+	struct spi_message msg;
+
+	struct {
+		/* Scan data for each channel */
+		u16 data[TI_TSC2046_MAX_CHAN];
+		/* Timestamp */
+		s64 ts __aligned(8);
+	} scan_buf;
+
+	/*
+	 * Lock to protect the layout and the SPI transfer buffer.
+	 * tsc2046_adc_group_layout can be changed within update_scan_mode(),
+	 * in this case the l[] and tx/rx buffer will be out of sync to each
+	 * other.
+	 */
+	struct mutex slock;
+	struct tsc2046_adc_group_layout l[TI_TSC2046_MAX_CHAN];
+	struct tsc2046_adc_atom *rx;
+	struct tsc2046_adc_atom *tx;
+
+	unsigned int count;
+	unsigned int groups;
+	u32 effective_speed_hz;
+	u32 scan_interval_us;
+	u32 time_per_scan_us;
+	u32 time_per_bit_ns;
+	unsigned int vref_mv;
+
+	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
+};
+
+#define TI_TSC2046_V_CHAN(index, bits, name)			\
+{								\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.channel = index,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+	.datasheet_name = "#name",				\
+	.scan_index = index,					\
+	.scan_type = {						\
+		.sign = 'u',					\
+		.realbits = bits,				\
+		.storagebits = 16,				\
+		.endianness = IIO_CPU,				\
+	},							\
+}
+
+#define DECLARE_TI_TSC2046_8_CHANNELS(name, bits) \
+const struct iio_chan_spec name ## _channels[] = { \
+	TI_TSC2046_V_CHAN(0, bits, TEMP0), \
+	TI_TSC2046_V_CHAN(1, bits, Y), \
+	TI_TSC2046_V_CHAN(2, bits, VBAT), \
+	TI_TSC2046_V_CHAN(3, bits, Z1), \
+	TI_TSC2046_V_CHAN(4, bits, Z2), \
+	TI_TSC2046_V_CHAN(5, bits, X), \
+	TI_TSC2046_V_CHAN(6, bits, AUX), \
+	TI_TSC2046_V_CHAN(7, bits, TEMP1), \
+	IIO_CHAN_SOFT_TIMESTAMP(8), \
+}
+
+static DECLARE_TI_TSC2046_8_CHANNELS(tsc2046_adc, 12);
+
+static const struct tsc2046_adc_dcfg tsc2046_adc_dcfg_tsc2046e = {
+	.channels = tsc2046_adc_channels,
+	.num_channels = ARRAY_SIZE(tsc2046_adc_channels),
+};
+
+/*
+ * Convert time to a number of samples which can be transferred within this
+ * time.
+ */
+static unsigned int tsc2046_adc_time_to_count(struct tsc2046_adc_priv *priv,
+					      unsigned long time)
+{
+	unsigned int bit_count, sample_count;
+
+	bit_count = DIV_ROUND_UP(time * NSEC_PER_USEC, priv->time_per_bit_ns);
+	sample_count = DIV_ROUND_UP(bit_count, TI_TSC2046_SAMPLE_BITS);
+
+	dev_dbg(&priv->spi->dev, "Effective speed %u, time per bit: %u, count bits: %u, count samples: %u\n",
+		priv->effective_speed_hz, priv->time_per_bit_ns,
+		bit_count, sample_count);
+
+	return sample_count;
+}
+
+static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
+			      bool keep_power)
+{
+	u32 pd;
+
+	/*
+	 * if PD bits are 0, controller will automatically disable ADC, VREF and
+	 * enable IRQ.
+	 */
+	if (keep_power)
+		pd = TI_TSC2046_PD0_ADC_ON;
+	else
+		pd = 0;
+
+	switch (ch_idx) {
+	case TI_TSC2046_ADDR_TEMP1:
+	case TI_TSC2046_ADDR_AUX:
+	case TI_TSC2046_ADDR_VBAT:
+	case TI_TSC2046_ADDR_TEMP0:
+		pd |= TI_TSC2046_SER;
+		if (!priv->vref_reg)
+			pd |= TI_TSC2046_PD1_VREF_ON;
+	}
+
+	return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
+}
+
+static u16 tsc2046_adc_get_value(struct tsc2046_adc_atom *buf)
+{
+	return FIELD_GET(TI_TSC2046_DATA_12BIT, get_unaligned_be16(&buf->data));
+}
+
+static int tsc2046_adc_read_one(struct tsc2046_adc_priv *priv, int ch_idx,
+				u32 *effective_speed_hz)
+{
+	struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx];
+	struct tsc2046_adc_atom *rx_buf, *tx_buf;
+	unsigned int val, val_normalized = 0;
+	int ret, i, count_skip = 0, max_count;
+	struct spi_transfer xfer;
+	struct spi_message msg;
+	u8 cmd;
+
+	if (!effective_speed_hz) {
+		count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us);
+		max_count = count_skip + ch->oversampling_ratio;
+	} else {
+		max_count = 1;
+	}
+
+	if (sizeof(*tx_buf) * max_count > PAGE_SIZE)
+		return -ENOSPC;
+
+	tx_buf = kcalloc(max_count, sizeof(*tx_buf), GFP_KERNEL);
+	if (!tx_buf)
+		return -ENOMEM;
+
+	rx_buf = kcalloc(max_count, sizeof(*rx_buf), GFP_KERNEL);
+	if (!rx_buf) {
+		ret = -ENOMEM;
+		goto free_tx;
+	}
+
+	/*
+	 * Do not enable automatic power down on working samples. Otherwise the
+	 * plates will never be completely charged.
+	 */
+	cmd = tsc2046_adc_get_cmd(priv, ch_idx, true);
+
+	for (i = 0; i < max_count - 1; i++)
+		tx_buf[i].cmd = cmd;
+
+	/* automatically power down on last sample */
+	tx_buf[i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false);
+
+	memset(&xfer, 0, sizeof(xfer));
+	xfer.tx_buf = tx_buf;
+	xfer.rx_buf = rx_buf;
+	xfer.len = sizeof(*tx_buf) * max_count;
+	spi_message_init_with_transfers(&msg, &xfer, 1);
+
+	/*
+	 * We aren't using spi_write_then_read() because we need to be able
+	 * to get hold of the effective_speed_hz from the xfer
+	 */
+	ret = spi_sync(priv->spi, &msg);
+	if (ret) {
+		dev_err_ratelimited(&priv->spi->dev, "SPI transfer failed %pe\n",
+				    ERR_PTR(ret));
+		goto free_bufs;
+	}
+
+	if (effective_speed_hz)
+		*effective_speed_hz = xfer.effective_speed_hz;
+
+	for (i = 0; i < max_count - count_skip; i++) {
+		val = tsc2046_adc_get_value(&rx_buf[count_skip + i]);
+		val_normalized += val;
+	}
+
+	ret = DIV_ROUND_UP(val_normalized, max_count - count_skip);
+
+free_bufs:
+	kfree(rx_buf);
+free_tx:
+	kfree(tx_buf);
+
+	return ret;
+}
+
+static size_t tsc2046_adc_group_set_layout(struct tsc2046_adc_priv *priv,
+					   unsigned int group,
+					   unsigned int ch_idx)
+{
+	struct tsc2046_adc_ch_cfg *ch = &priv->ch_cfg[ch_idx];
+	struct tsc2046_adc_group_layout *cur;
+	unsigned int max_count, count_skip;
+	unsigned int offset = 0;
+
+	if (group)
+		offset = priv->l[group - 1].offset + priv->l[group - 1].count;
+
+	count_skip = tsc2046_adc_time_to_count(priv, ch->settling_time_us);
+	max_count = count_skip + ch->oversampling_ratio;
+
+	cur = &priv->l[group];
+	cur->offset = offset;
+	cur->count = max_count;
+	cur->skip = count_skip;
+
+	return sizeof(*priv->tx) * max_count;
+}
+
+static void tsc2046_adc_group_set_cmd(struct tsc2046_adc_priv *priv,
+				      unsigned int group, int ch_idx)
+{
+	struct tsc2046_adc_group_layout *l = &priv->l[group];
+	unsigned int i;
+	u8 cmd;
+
+	/*
+	 * Do not enable automatic power down on working samples. Otherwise the
+	 * plates will never be completely charged.
+	 */
+	cmd = tsc2046_adc_get_cmd(priv, ch_idx, true);
+
+	for (i = 0; i < l->count - 1; i++)
+		priv->tx[l->offset + i].cmd = cmd;
+
+	/* automatically power down on last sample */
+	priv->tx[l->offset + i].cmd = tsc2046_adc_get_cmd(priv, ch_idx, false);
+}
+
+static u16 tsc2046_adc_get_val(struct tsc2046_adc_priv *priv, int group)
+{
+	struct tsc2046_adc_group_layout *l;
+	unsigned int val, val_normalized = 0;
+	int valid_count, i;
+
+	l = &priv->l[group];
+	valid_count = l->count - l->skip;
+
+	for (i = 0; i < valid_count; i++) {
+		val = tsc2046_adc_get_value(&priv->rx[l->offset + l->skip + i]);
+		val_normalized += val;
+	}
+
+	return DIV_ROUND_UP(val_normalized, valid_count);
+}
+
+static int tsc2046_adc_scan(struct iio_dev *indio_dev)
+{
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	struct device *dev = &priv->spi->dev;
+	int group;
+	int ret;
+
+	ret = spi_sync(priv->spi, &priv->msg);
+	if (ret < 0) {
+		dev_err_ratelimited(dev, "SPI transfer failed: %pe\n", ERR_PTR(ret));
+		return ret;
+	}
+
+	for (group = 0; group < priv->groups; group++)
+		priv->scan_buf.data[group] = tsc2046_adc_get_val(priv, group);
+
+	ret = iio_push_to_buffers_with_timestamp(indio_dev, &priv->scan_buf,
+						 iio_get_time_ns(indio_dev));
+	/* If the consumer is kfifo, we may get a EBUSY here - ignore it. */
+	if (ret < 0 && ret != -EBUSY) {
+		dev_err_ratelimited(dev, "Failed to push scan buffer %pe\n",
+				    ERR_PTR(ret));
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static irqreturn_t tsc2046_adc_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+
+	mutex_lock(&priv->slock);
+	tsc2046_adc_scan(indio_dev);
+	mutex_unlock(&priv->slock);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int *val, int *val2, long m)
+{
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	switch (m) {
+	case IIO_CHAN_INFO_RAW:
+		ret = tsc2046_adc_read_one(priv, chan->channel, NULL);
+		if (ret < 0)
+			return ret;
+
+		*val = ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * Note: the TSC2046 has internal voltage divider on the VBAT
+		 * line. This divider can be influenced by external divider.
+		 * So, it is better to use external voltage-divider driver
+		 * instead, which is calculating complete chain.
+		 */
+		*val = priv->vref_mv;
+		*val2 = chan->scan_type.realbits;
+		return IIO_VAL_FRACTIONAL_LOG2;
+	}
+
+	return -EINVAL;
+}
+
+static int tsc2046_adc_update_scan_mode(struct iio_dev *indio_dev,
+					const unsigned long *active_scan_mask)
+{
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	unsigned int ch_idx, group = 0;
+	size_t size;
+
+	mutex_lock(&priv->slock);
+
+	size = 0;
+	for_each_set_bit(ch_idx, active_scan_mask, ARRAY_SIZE(priv->l)) {
+		size += tsc2046_adc_group_set_layout(priv, group, ch_idx);
+		tsc2046_adc_group_set_cmd(priv, group, ch_idx);
+		group++;
+	}
+
+	priv->groups = group;
+	priv->xfer.len = size;
+	priv->time_per_scan_us = size * 8 * priv->time_per_bit_ns / NSEC_PER_USEC;
+
+	if (priv->scan_interval_us < priv->time_per_scan_us)
+		dev_warn(&priv->spi->dev, "The scan interval (%d) is less then calculated scan time (%d)\n",
+			 priv->scan_interval_us, priv->time_per_scan_us);
+
+	mutex_unlock(&priv->slock);
+
+	return 0;
+}
+
+static const struct iio_info tsc2046_adc_info = {
+	.read_raw	  = tsc2046_adc_read_raw,
+	.update_scan_mode = tsc2046_adc_update_scan_mode,
+};
+
+static enum hrtimer_restart tsc2046_adc_timer(struct hrtimer *hrtimer)
+{
+	struct tsc2046_adc_priv *priv = container_of(hrtimer,
+						     struct tsc2046_adc_priv,
+						     trig_timer);
+	unsigned long flags;
+
+	/*
+	 * This state machine should address following challenges :
+	 * - the interrupt source is based on level shifter attached to the X
+	 *   channel of ADC. It will change the state every time we switch
+	 *   between channels. So, we need to disable IRQ if we do
+	 *   iio_trigger_poll().
+	 * - we should do iio_trigger_poll() at some reduced sample rate
+	 * - we should still trigger for some amount of time after last
+	 *   interrupt with enabled IRQ was processed.
+	 */
+
+	spin_lock_irqsave(&priv->state_lock, flags);
+	switch (priv->state) {
+	case TSC2046_STATE_ENABLE_IRQ:
+		if (priv->poll_cnt < TI_TSC2046_POLL_CNT) {
+			priv->poll_cnt++;
+			hrtimer_start(&priv->trig_timer,
+				      ns_to_ktime(priv->scan_interval_us *
+						  NSEC_PER_USEC),
+				      HRTIMER_MODE_REL_SOFT);
+
+			if (priv->poll_cnt >= TI_TSC2046_MIN_POLL_CNT) {
+				priv->state = TSC2046_STATE_POLL_IRQ_DISABLE;
+				enable_irq(priv->spi->irq);
+			} else {
+				priv->state = TSC2046_STATE_POLL;
+			}
+		} else {
+			priv->state = TSC2046_STATE_STANDBY;
+			enable_irq(priv->spi->irq);
+		}
+		break;
+	case TSC2046_STATE_POLL_IRQ_DISABLE:
+		disable_irq_nosync(priv->spi->irq);
+		fallthrough;
+	case TSC2046_STATE_POLL:
+		priv->state = TSC2046_STATE_ENABLE_IRQ;
+		/* iio_trigger_poll() starts hrtimer */
+		iio_trigger_poll(priv->trig);
+		break;
+	case TSC2046_STATE_SHUTDOWN:
+		break;
+	case TSC2046_STATE_STANDBY:
+		fallthrough;
+	default:
+		dev_warn(&priv->spi->dev, "Got unexpected state: %i\n",
+			 priv->state);
+		break;
+	}
+	spin_unlock_irqrestore(&priv->state_lock, flags);
+
+	return HRTIMER_NORESTART;
+}
+
+static irqreturn_t tsc2046_adc_irq(int irq, void *dev_id)
+{
+	struct iio_dev *indio_dev = dev_id;
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	unsigned long flags;
+
+	hrtimer_try_to_cancel(&priv->trig_timer);
+
+	spin_lock_irqsave(&priv->state_lock, flags);
+	if (priv->state != TSC2046_STATE_SHUTDOWN) {
+		priv->state = TSC2046_STATE_ENABLE_IRQ;
+		priv->poll_cnt = 0;
+
+		/* iio_trigger_poll() starts hrtimer */
+		disable_irq_nosync(priv->spi->irq);
+		iio_trigger_poll(priv->trig);
+	}
+	spin_unlock_irqrestore(&priv->state_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static void tsc2046_adc_reenable_trigger(struct iio_trigger *trig)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	ktime_t tim;
+
+	/*
+	 * We can sample it as fast as we can, but usually we do not need so
+	 * many samples. Reduce the sample rate for default (touchscreen) use
+	 * case.
+	 */
+	tim = ns_to_ktime((priv->scan_interval_us - priv->time_per_scan_us) *
+			  NSEC_PER_USEC);
+	hrtimer_start(&priv->trig_timer, tim, HRTIMER_MODE_REL_SOFT);
+}
+
+static int tsc2046_adc_set_trigger_state(struct iio_trigger *trig, bool enable)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
+	unsigned long flags;
+
+	if (enable) {
+		spin_lock_irqsave(&priv->state_lock, flags);
+		if (priv->state == TSC2046_STATE_SHUTDOWN) {
+			priv->state = TSC2046_STATE_STANDBY;
+			enable_irq(priv->spi->irq);
+		}
+		spin_unlock_irqrestore(&priv->state_lock, flags);
+	} else {
+		spin_lock_irqsave(&priv->state_lock, flags);
+
+		if (priv->state == TSC2046_STATE_STANDBY ||
+		    priv->state == TSC2046_STATE_POLL_IRQ_DISABLE)
+			disable_irq_nosync(priv->spi->irq);
+
+		priv->state = TSC2046_STATE_SHUTDOWN;
+		spin_unlock_irqrestore(&priv->state_lock, flags);
+
+		hrtimer_cancel(&priv->trig_timer);
+	}
+
+	return 0;
+}
+
+static const struct iio_trigger_ops tsc2046_adc_trigger_ops = {
+	.set_trigger_state = tsc2046_adc_set_trigger_state,
+	.reenable = tsc2046_adc_reenable_trigger,
+};
+
+static int tsc2046_adc_setup_spi_msg(struct tsc2046_adc_priv *priv)
+{
+	unsigned int ch_idx;
+	size_t size;
+	int ret;
+
+	/*
+	 * Make dummy read to set initial power state and get real SPI clock
+	 * freq. It seems to be not important which channel is used for this
+	 * case.
+	 */
+	ret = tsc2046_adc_read_one(priv, TI_TSC2046_ADDR_TEMP0,
+				   &priv->effective_speed_hz);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * In case SPI controller do not report effective_speed_hz, use
+	 * configure value and hope it will match.
+	 */
+	if (!priv->effective_speed_hz)
+		priv->effective_speed_hz = priv->spi->max_speed_hz;
+
+
+	priv->scan_interval_us = TI_TSC2046_SAMPLE_INTERVAL_US;
+	priv->time_per_bit_ns = DIV_ROUND_UP(NSEC_PER_SEC,
+					     priv->effective_speed_hz);
+
+	/*
+	 * Calculate and allocate maximal size buffer if all channels are
+	 * enabled.
+	 */
+	size = 0;
+	for (ch_idx = 0; ch_idx < ARRAY_SIZE(priv->l); ch_idx++)
+		size += tsc2046_adc_group_set_layout(priv, ch_idx, ch_idx);
+
+	if (size > PAGE_SIZE) {
+		dev_err(&priv->spi->dev,
+			"Calculated scan buffer is too big. Try to reduce spi-max-frequency, settling-time-us or oversampling-ratio\n");
+		return -ENOSPC;
+	}
+
+	priv->tx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL);
+	if (!priv->tx)
+		return -ENOMEM;
+
+	priv->rx = devm_kzalloc(&priv->spi->dev, size, GFP_KERNEL);
+	if (!priv->rx)
+		return -ENOMEM;
+
+	priv->xfer.tx_buf = priv->tx;
+	priv->xfer.rx_buf = priv->rx;
+	priv->xfer.len = size;
+	spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
+
+	return 0;
+}
+
+static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv)
+{
+	struct fwnode_handle *child;
+	struct device *dev = &priv->spi->dev;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(priv->ch_cfg); i++) {
+		priv->ch_cfg[i].settling_time_us = 1;
+		priv->ch_cfg[i].oversampling_ratio = 1;
+	}
+
+	device_for_each_child_node(dev, child) {
+		u32 stl, overs, reg;
+		int ret;
+
+		ret = fwnode_property_read_u32(child, "reg", &reg);
+		if (ret) {
+			dev_err(dev, "invalid reg on %pfw, err: %pe\n", child,
+				ERR_PTR(ret));
+			continue;
+		}
+
+		if (reg >= ARRAY_SIZE(priv->ch_cfg)) {
+			dev_err(dev, "%pfw: Unsupported reg value: %i, max supported is: %zu.\n",
+				child, reg, ARRAY_SIZE(priv->ch_cfg));
+			continue;
+		}
+
+		ret = fwnode_property_read_u32(child, "settling-time-us", &stl);
+		if (!ret)
+			priv->ch_cfg[reg].settling_time_us = stl;
+
+		ret = fwnode_property_read_u32(child, "oversampling-ratio",
+					       &overs);
+		if (!ret)
+			priv->ch_cfg[reg].oversampling_ratio = overs;
+	}
+}
+
+static void tsc2046_adc_regulator_disable(void *data)
+{
+	struct tsc2046_adc_priv *priv = data;
+
+	regulator_disable(priv->vref_reg);
+}
+
+static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv)
+{
+	struct device *dev = &priv->spi->dev;
+	int ret;
+
+	priv->vref_reg = devm_regulator_get_optional(dev, "vref");
+	if (IS_ERR(priv->vref_reg)) {
+		/* If regulator exists but can't be get, return an error */
+		if (PTR_ERR(priv->vref_reg) != -ENODEV)
+			return PTR_ERR(priv->vref_reg);
+		priv->vref_reg = NULL;
+	}
+	if (!priv->vref_reg) {
+		/* Use internal reference */
+		priv->vref_mv = TI_TSC2046_INT_VREF;
+		return 0;
+	}
+
+	ret = regulator_enable(priv->vref_reg);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable,
+				       priv);
+	if (ret)
+		return ret;
+
+	ret = regulator_get_voltage(priv->vref_reg);
+	if (ret < 0)
+		return ret;
+
+	priv->vref_mv = ret / MILLI;
+
+	return 0;
+}
+
+static int tsc2046_adc_probe(struct spi_device *spi)
+{
+	const struct tsc2046_adc_dcfg *dcfg;
+	struct device *dev = &spi->dev;
+	struct tsc2046_adc_priv *priv;
+	struct iio_dev *indio_dev;
+	struct iio_trigger *trig;
+	int ret;
+
+	if (spi->max_speed_hz > TI_TSC2046_MAX_CLK_FREQ) {
+		dev_err(dev, "SPI max_speed_hz is too high: %d Hz. Max supported freq is %zu Hz\n",
+			spi->max_speed_hz, TI_TSC2046_MAX_CLK_FREQ);
+		return -EINVAL;
+	}
+
+	dcfg = device_get_match_data(dev);
+	if (!dcfg) {
+		const struct spi_device_id *id = spi_get_device_id(spi);
+
+		dcfg = (const struct tsc2046_adc_dcfg *)id->driver_data;
+	}
+	if (!dcfg)
+		return -EINVAL;
+
+	spi->bits_per_word = 8;
+	spi->mode &= ~SPI_MODE_X_MASK;
+	spi->mode |= SPI_MODE_0;
+	ret = spi_setup(spi);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Error in SPI setup\n");
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	priv->dcfg = dcfg;
+
+	priv->spi = spi;
+
+	indio_dev->name = TI_TSC2046_NAME;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = dcfg->channels;
+	indio_dev->num_channels = dcfg->num_channels;
+	indio_dev->info = &tsc2046_adc_info;
+
+	ret = tsc2046_adc_configure_regulator(priv);
+	if (ret)
+		return ret;
+
+	tsc2046_adc_parse_fwnode(priv);
+
+	ret = tsc2046_adc_setup_spi_msg(priv);
+	if (ret)
+		return ret;
+
+	mutex_init(&priv->slock);
+
+	ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
+			       IRQF_NO_AUTOEN, indio_dev->name, indio_dev);
+	if (ret)
+		return ret;
+
+	trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
+	if (!trig)
+		return -ENOMEM;
+
+	priv->trig = trig;
+	iio_trigger_set_drvdata(trig, indio_dev);
+	trig->ops = &tsc2046_adc_trigger_ops;
+
+	spin_lock_init(&priv->state_lock);
+	priv->state = TSC2046_STATE_SHUTDOWN;
+	hrtimer_init(&priv->trig_timer, CLOCK_MONOTONIC,
+		     HRTIMER_MODE_REL_SOFT);
+	priv->trig_timer.function = tsc2046_adc_timer;
+
+	ret = devm_iio_trigger_register(dev, trig);
+	if (ret) {
+		dev_err(dev, "failed to register trigger\n");
+		return ret;
+	}
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+					      &tsc2046_adc_trigger_handler, NULL);
+	if (ret) {
+		dev_err(dev, "Failed to setup triggered buffer\n");
+		return ret;
+	}
+
+	/* set default trigger */
+	indio_dev->trig = iio_trigger_get(priv->trig);
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id ads7950_of_table[] = {
+	{ .compatible = "ti,tsc2046e-adc", .data = &tsc2046_adc_dcfg_tsc2046e },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ads7950_of_table);
+
+static const struct spi_device_id tsc2046_adc_spi_ids[] = {
+	{ "tsc2046e-adc", (unsigned long)&tsc2046_adc_dcfg_tsc2046e },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, tsc2046_adc_spi_ids);
+
+static struct spi_driver tsc2046_adc_driver = {
+	.driver = {
+		.name = "tsc2046",
+		.of_match_table = ads7950_of_table,
+	},
+	.id_table = tsc2046_adc_spi_ids,
+	.probe = tsc2046_adc_probe,
+};
+module_spi_driver(tsc2046_adc_driver);
+
+MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("TI TSC2046 ADC");
+MODULE_LICENSE("GPL v2");