[PATCH v2 0/3] iio: gyro: adxrs290: Add triggered buffer & debugfs support

[PATCH v2 0/3] iio: gyro: adxrs290: Add triggered buffer & debugfs support

[Nishant Malpani]

Introduce DATA_RDY trigger for triggered buffer setup; this enables continuous
data capture. Additionally, add support for direct register access using the debugfs 
iio interface. 

The device-tree bindings documentation illustrates an example of using a GPIO irq
line to trigger a data capture.

Nishant Malpani (3):
  iio: gyro: adxrs290: Add triggered buffer support
  dt-bindings: iio: gyro: adxrs290: Add interrupts support
  iio: gyro: adxrs290: Add debugfs register access support

 .../bindings/iio/gyroscope/adi,adxrs290.yaml  |   7 +
 drivers/iio/gyro/Kconfig                      |   2 +
 drivers/iio/gyro/adxrs290.c                   | 284 +++++++++++++++++-
 3 files changed, 279 insertions(+), 14 deletions(-)

-- 
2.20.1

[PATCH v2 1/3] iio: gyro: adxrs290: Add triggered buffer support

[Nishant Malpani]

Provide a way for continuous data capture by setting up buffer support. The
data ready signal exposed at the SYNC pin of the ADXRS290 is exploited as
a hardware interrupt which triggers to fill the buffer.

Triggered buffer setup was tested with both hardware trigger (DATA_RDY) and
software triggers (sysfs-trig & hrtimer).

Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>
---

Changes in v2:

  - In adxrs290_set_mode(), move 'if' block outside the locked section
  - use break statement for error handling instead of goto labels in
    switch-case blocks
  - remove outer parentheses when conditional ternary operator is used
  - use dev_err_probe() saving a few lines of code
  - re-align 'buffer' variable name in 'struct adxrs290_state'
  - don't return errors in 'try_reenable' callback
  - use 'st->spi' inline in 'adxrs290_trigger_handler'
  - unnecessary to mention default 'shift' (= 0) in
    iio_chan_spec.scan_type
  - bring in consistent wrapping of parameters while staying under
    the advised 80 chars line limit
---
 drivers/iio/gyro/Kconfig    |   2 +
 drivers/iio/gyro/adxrs290.c | 265 ++++++++++++++++++++++++++++++++++--
 2 files changed, 253 insertions(+), 14 deletions(-)

diff --git a/drivers/iio/gyro/Kconfig b/drivers/iio/gyro/Kconfig
index 024a34139875..5824f2edf975 100644
--- a/drivers/iio/gyro/Kconfig
+++ b/drivers/iio/gyro/Kconfig
@@ -44,6 +44,8 @@ config ADIS16260
 config ADXRS290
 	tristate "Analog Devices ADXRS290 Dual-Axis MEMS Gyroscope SPI driver"
 	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Say yes here to build support for Analog Devices ADXRS290 programmable
 	  digital output gyroscope.
diff --git a/drivers/iio/gyro/adxrs290.c b/drivers/iio/gyro/adxrs290.c
index ff989536d2fb..4099b8917d3e 100644
--- a/drivers/iio/gyro/adxrs290.c
+++ b/drivers/iio/gyro/adxrs290.c
@@ -13,8 +13,12 @@
 #include <linux/module.h>
 #include <linux/spi/spi.h>
 
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
 
 #define ADXRS290_ADI_ID		0xAD
 #define ADXRS290_MEMS_ID	0x1D
@@ -35,7 +39,9 @@
 #define ADXRS290_READ		BIT(7)
 #define ADXRS290_TSM		BIT(0)
 #define ADXRS290_MEASUREMENT	BIT(1)
-#define ADXRS290_SYNC		GENMASK(1, 0)
+#define ADXRS290_DATA_RDY_OUT	BIT(0)
+#define ADXRS290_SYNC_MASK	GENMASK(1, 0)
+#define ADXRS290_SYNC(x)	FIELD_PREP(ADXRS290_SYNC_MASK, x)
 #define ADXRS290_LPF_MASK	GENMASK(2, 0)
 #define ADXRS290_LPF(x)		FIELD_PREP(ADXRS290_LPF_MASK, x)
 #define ADXRS290_HPF_MASK	GENMASK(7, 4)
@@ -50,6 +56,13 @@ enum adxrs290_mode {
 	ADXRS290_MODE_MEASUREMENT,
 };
 
+enum adxrs290_scan_index {
+	ADXRS290_IDX_X,
+	ADXRS290_IDX_Y,
+	ADXRS290_IDX_TEMP,
+	ADXRS290_IDX_TS,
+};
+
 struct adxrs290_state {
 	struct spi_device	*spi;
 	/* Serialize reads and their subsequent processing */
@@ -57,6 +70,12 @@ struct adxrs290_state {
 	enum adxrs290_mode	mode;
 	unsigned int		lpf_3db_freq_idx;
 	unsigned int		hpf_3db_freq_idx;
+	struct iio_trigger      *dready_trig;
+	/* Ensure correct alignment of timestamp when present */
+	struct {
+		s16 channels[3];
+		s64 ts __aligned(8);
+	} buffer;
 };
 
 /*
@@ -192,6 +211,52 @@ static int adxrs290_set_filter_freq(struct iio_dev *indio_dev,
 	return adxrs290_spi_write_reg(st->spi, ADXRS290_REG_FILTER, val);
 }
 
+static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
+{
+	struct adxrs290_state *st = iio_priv(indio_dev);
+	int val, ret;
+
+	if (st->mode == mode) {
+		ret = 0;
+		goto done;
+	}
+
+	mutex_lock(&st->lock);
+
+	ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
+	if (ret < 0)
+		goto done;
+
+	val = ret;
+
+	switch (mode) {
+	case ADXRS290_MODE_STANDBY:
+		val &= ~ADXRS290_MEASUREMENT;
+		break;
+	case ADXRS290_MODE_MEASUREMENT:
+		val |= ADXRS290_MEASUREMENT;
+		break;
+	default:
+		ret = -EINVAL;
+		goto done;
+	}
+
+	ret = adxrs290_spi_write_reg(st->spi,
+				     ADXRS290_REG_POWER_CTL,
+				     val);
+	if (ret < 0) {
+		dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
+		goto done;
+	}
+
+	/* update cached mode */
+	st->mode = mode;
+
+done:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
 static int adxrs290_initial_setup(struct iio_dev *indio_dev)
 {
 	struct adxrs290_state *st = iio_priv(indio_dev);
@@ -203,6 +268,13 @@ static int adxrs290_initial_setup(struct iio_dev *indio_dev)
 				      ADXRS290_MEASUREMENT | ADXRS290_TSM);
 }
 
+static void adxrs290_chip_off_action(void *data)
+{
+	struct iio_dev *indio_dev = data;
+
+	adxrs290_set_mode(indio_dev, ADXRS290_MODE_STANDBY);
+}
+
 static int adxrs290_read_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int *val,
@@ -215,24 +287,34 @@ static int adxrs290_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
 			ret = adxrs290_get_rate_data(indio_dev,
 						     ADXRS290_READ_REG(chan->address),
 						     val);
 			if (ret < 0)
-				return ret;
+				break;
 
-			return IIO_VAL_INT;
+			ret = IIO_VAL_INT;
+			break;
 		case IIO_TEMP:
 			ret = adxrs290_get_temp_data(indio_dev, val);
 			if (ret < 0)
-				return ret;
+				break;
 
-			return IIO_VAL_INT;
+			ret = IIO_VAL_INT;
+			break;
 		default:
-			return -EINVAL;
+			ret = -EINVAL;
+			break;
 		}
+
+		iio_device_release_direct_mode(indio_dev);
+		return ret;
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_ANGL_VEL:
@@ -279,34 +361,52 @@ static int adxrs290_write_raw(struct iio_dev *indio_dev,
 			      long mask)
 {
 	struct adxrs290_state *st = iio_priv(indio_dev);
-	int lpf_idx, hpf_idx;
+	int ret, lpf_idx, hpf_idx;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
 		lpf_idx = adxrs290_find_match(adxrs290_lpf_3db_freq_hz_table,
 					      ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table),
 					      val, val2);
-		if (lpf_idx < 0)
-			return -EINVAL;
+		if (lpf_idx < 0) {
+			ret = -EINVAL;
+			break;
+		}
+
 		/* caching the updated state of the low-pass filter */
 		st->lpf_3db_freq_idx = lpf_idx;
 		/* retrieving the current state of the high-pass filter */
 		hpf_idx = st->hpf_3db_freq_idx;
-		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
+		ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
+		break;
+
 	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
 		hpf_idx = adxrs290_find_match(adxrs290_hpf_3db_freq_hz_table,
 					      ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table),
 					      val, val2);
-		if (hpf_idx < 0)
-			return -EINVAL;
+		if (hpf_idx < 0) {
+			ret = -EINVAL;
+			break;
+		}
+
 		/* caching the updated state of the high-pass filter */
 		st->hpf_3db_freq_idx = hpf_idx;
 		/* retrieving the current state of the low-pass filter */
 		lpf_idx = st->lpf_3db_freq_idx;
-		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
+		ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
 	}
 
-	return -EINVAL;
+	iio_device_release_direct_mode(indio_dev);
+	return ret;
 }
 
 static int adxrs290_read_avail(struct iio_dev *indio_dev,
@@ -334,6 +434,69 @@ static int adxrs290_read_avail(struct iio_dev *indio_dev,
 	}
 }
 
+static int adxrs290_data_rdy_trigger_set_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct adxrs290_state *st = iio_priv(indio_dev);
+	int ret;
+	u8 val;
+
+	val = state ? ADXRS290_SYNC(ADXRS290_DATA_RDY_OUT) : 0;
+
+	ret = adxrs290_spi_write_reg(st->spi, ADXRS290_REG_DATA_RDY, val);
+	if (ret < 0)
+		dev_err(&st->spi->dev, "failed to start data ready interrupt\n");
+
+	return ret;
+}
+
+static int adxrs290_reset_trig(struct iio_trigger *trig)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	int val;
+
+	/*
+	 * Data ready interrupt is reset after a read of the data registers.
+	 * Here, we only read the 16b DATAY registers as that marks the end of
+	 * a read of the data registers and initiates a reset for the interrupt line.
+	 */
+	adxrs290_get_rate_data(indio_dev, ADXRS290_READ_REG(ADXRS290_REG_DATAY0), &val);
+
+	return 0;
+}
+
+static const struct iio_trigger_ops adxrs290_trigger_ops = {
+	.set_trigger_state = &adxrs290_data_rdy_trigger_set_state,
+	.validate_device = &iio_trigger_validate_own_device,
+	.try_reenable = &adxrs290_reset_trig,
+};
+
+static irqreturn_t adxrs290_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct adxrs290_state *st = iio_priv(indio_dev);
+	u8 tx = ADXRS290_READ_REG(ADXRS290_REG_DATAX0);
+	int ret;
+
+	mutex_lock(&st->lock);
+
+	/* exercise a bulk data capture starting from reg DATAX0... */
+	ret = spi_write_then_read(st->spi, &tx, sizeof(tx), st->buffer.channels,
+				  sizeof(st->buffer.channels));
+	if (ret < 0)
+		goto done;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
+					   pf->timestamp);
+
+done:
+	mutex_unlock(&st->lock);
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
 #define ADXRS290_ANGL_VEL_CHANNEL(reg, axis) {				\
 	.type = IIO_ANGL_VEL,						\
 	.address = reg,							\
@@ -346,6 +509,13 @@ static int adxrs290_read_avail(struct iio_dev *indio_dev,
 	.info_mask_shared_by_type_available =				\
 	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |		\
 	BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),		\
+	.scan_index = ADXRS290_IDX_##axis,				\
+	.scan_type = {                                                  \
+		.sign = 's',                                            \
+		.realbits = 16,                                         \
+		.storagebits = 16,                                      \
+		.endianness = IIO_LE,					\
+	},                                                              \
 }
 
 static const struct iio_chan_spec adxrs290_channels[] = {
@@ -356,7 +526,20 @@ static const struct iio_chan_spec adxrs290_channels[] = {
 		.address = ADXRS290_REG_TEMP0,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 		BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = ADXRS290_IDX_TEMP,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 12,
+			.storagebits = 16,
+			.endianness = IIO_LE,
+		},
 	},
+	IIO_CHAN_SOFT_TIMESTAMP(ADXRS290_IDX_TS),
+};
+
+static const unsigned long adxrs290_avail_scan_masks[] = {
+	BIT(ADXRS290_IDX_X) | BIT(ADXRS290_IDX_Y) | BIT(ADXRS290_IDX_TEMP),
+	0
 };
 
 static const struct iio_info adxrs290_info = {
@@ -365,6 +548,43 @@ static const struct iio_info adxrs290_info = {
 	.read_avail = &adxrs290_read_avail,
 };
 
+static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
+{
+	struct adxrs290_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!st->spi->irq) {
+		dev_info(&st->spi->dev, "no irq, using polling\n");
+		return 0;
+	}
+
+	st->dready_trig = devm_iio_trigger_alloc(&st->spi->dev, "%s-dev%d",
+						 indio_dev->name,
+						 indio_dev->id);
+	if (!st->dready_trig)
+		return -ENOMEM;
+
+	st->dready_trig->dev.parent = &st->spi->dev;
+	st->dready_trig->ops = &adxrs290_trigger_ops;
+	iio_trigger_set_drvdata(st->dready_trig, indio_dev);
+
+	ret = devm_request_irq(&st->spi->dev, st->spi->irq,
+			       &iio_trigger_generic_data_rdy_poll,
+			       IRQF_ONESHOT, "adxrs290_irq", st->dready_trig);
+	if (ret < 0)
+		return dev_err_probe(&st->spi->dev, ret,
+				     "request irq %d failed\n", st->spi->irq);
+
+	ret = devm_iio_trigger_register(&st->spi->dev, st->dready_trig);
+	if (ret)
+		return dev_err_probe(&st->spi->dev, ret,
+				     "iio trigger register failed\n");
+
+	indio_dev->trig = iio_trigger_get(st->dready_trig);
+
+	return 0;
+}
+
 static int adxrs290_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
@@ -384,6 +604,7 @@ static int adxrs290_probe(struct spi_device *spi)
 	indio_dev->channels = adxrs290_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adxrs290_channels);
 	indio_dev->info = &adxrs290_info;
+	indio_dev->available_scan_masks = adxrs290_avail_scan_masks;
 
 	mutex_init(&st->lock);
 
@@ -416,6 +637,11 @@ static int adxrs290_probe(struct spi_device *spi)
 	/* max transition time to measurement mode */
 	msleep(ADXRS290_MAX_TRANSITION_TIME_MS);
 
+	ret = devm_add_action_or_reset(&spi->dev, adxrs290_chip_off_action,
+				       indio_dev);
+	if (ret < 0)
+		return ret;
+
 	ret = adxrs290_get_3db_freq(indio_dev, &val, &val2);
 	if (ret < 0)
 		return ret;
@@ -423,6 +649,17 @@ static int adxrs290_probe(struct spi_device *spi)
 	st->lpf_3db_freq_idx = val;
 	st->hpf_3db_freq_idx = val2;
 
+	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+					      &iio_pollfunc_store_time,
+					      &adxrs290_trigger_handler, NULL);
+	if (ret < 0)
+		return dev_err_probe(&spi->dev, ret,
+				     "iio triggered buffer setup failed\n");
+
+	ret = adxrs290_probe_trigger(indio_dev);
+	if (ret < 0)
+		return ret;
+
 	return devm_iio_device_register(&spi->dev, indio_dev);
 }
 
-- 
2.20.1

Re: [PATCH v2 1/3] iio: gyro: adxrs290: Add triggered buffer support

[Andy Shevchenko]

On Thu, Sep 3, 2020 at 4:10 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
>
> Provide a way for continuous data capture by setting up buffer support. The
> data ready signal exposed at the SYNC pin of the ADXRS290 is exploited as
> a hardware interrupt which triggers to fill the buffer.
>
> Triggered buffer setup was tested with both hardware trigger (DATA_RDY) and
> software triggers (sysfs-trig & hrtimer).

...

> +static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
> +{
> +       struct adxrs290_state *st = iio_priv(indio_dev);
> +       int val, ret;
> +
> +       if (st->mode == mode) {

> +               ret = 0;
> +               goto done;

Unlocking the not locked mutex is not good. Have you followed the
Submitting Patches Checklist? It in particular suggests few debug
options, like LOCKDEP, to be enabled.

> +       }
> +
> +       mutex_lock(&st->lock);
> +
> +       ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
> +       if (ret < 0)
> +               goto done;
> +
> +       val = ret;
> +
> +       switch (mode) {
> +       case ADXRS290_MODE_STANDBY:
> +               val &= ~ADXRS290_MEASUREMENT;
> +               break;
> +       case ADXRS290_MODE_MEASUREMENT:
> +               val |= ADXRS290_MEASUREMENT;
> +               break;
> +       default:
> +               ret = -EINVAL;
> +               goto done;
> +       }
> +
> +       ret = adxrs290_spi_write_reg(st->spi,
> +                                    ADXRS290_REG_POWER_CTL,
> +                                    val);
> +       if (ret < 0) {
> +               dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
> +               goto done;
> +       }
> +
> +       /* update cached mode */
> +       st->mode = mode;
> +

> +done:

Much better to call it out_unlock. It will help eliminate the mistakes
like above.

> +       mutex_unlock(&st->lock);
> +       return ret;
> +}

...


What about

  ret = -EINVAL;

>         switch (mask) {
>         case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
>                 lpf_idx = adxrs290_find_match(adxrs290_lpf_3db_freq_hz_table,
>                                               ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table),
>                                               val, val2);
> -               if (lpf_idx < 0)
> -                       return -EINVAL;

> +               if (lpf_idx < 0) {

> +                       ret = -EINVAL;
> +                       break;
> +               }

Simple
  break;

and so on?

> +
>                 /* caching the updated state of the low-pass filter */
>                 st->lpf_3db_freq_idx = lpf_idx;
>                 /* retrieving the current state of the high-pass filter */
>                 hpf_idx = st->hpf_3db_freq_idx;
> -               return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +               ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +               break;
> +
>         case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
>                 hpf_idx = adxrs290_find_match(adxrs290_hpf_3db_freq_hz_table,
>                                               ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table),
>                                               val, val2);
> -               if (hpf_idx < 0)
> -                       return -EINVAL;
> +               if (hpf_idx < 0) {
> +                       ret = -EINVAL;
> +                       break;
> +               }
> +
>                 /* caching the updated state of the high-pass filter */
>                 st->hpf_3db_freq_idx = hpf_idx;
>                 /* retrieving the current state of the low-pass filter */
>                 lpf_idx = st->lpf_3db_freq_idx;
> -               return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +               ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +               break;
> +
> +       default:
> +               ret = -EINVAL;
> +               break;
>         }
>
> -       return -EINVAL;
> +       iio_device_release_direct_mode(indio_dev);
> +       return ret;
>  }

...

> +static irqreturn_t adxrs290_trigger_handler(int irq, void *p)
> +{

> +       /* exercise a bulk data capture starting from reg DATAX0... */
> +       ret = spi_write_then_read(st->spi, &tx, sizeof(tx), st->buffer.channels,
> +                                 sizeof(st->buffer.channels));
> +       if (ret < 0)
> +               goto done;
> +
> +       iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
> +                                          pf->timestamp);
> +
> +done:

out_unlock_notify:

> +       mutex_unlock(&st->lock);
> +       iio_trigger_notify_done(indio_dev->trig);
> +
> +       return IRQ_HANDLED;
> +}

...

> +static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
> +{
> +       struct adxrs290_state *st = iio_priv(indio_dev);
> +       int ret;

> +       if (!st->spi->irq) {
> +               dev_info(&st->spi->dev, "no irq, using polling\n");
> +               return 0;
> +       }

Wouldn't it be better to have this check outside of the function?
And taking this into account...

> +}

...

> +       ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> +                                             &iio_pollfunc_store_time,
> +                                             &adxrs290_trigger_handler, NULL);
> +       if (ret < 0)
> +               return dev_err_probe(&spi->dev, ret,
> +                                    "iio triggered buffer setup failed\n");

...do you really have to set up a trigger buffer w/o trigger being probed?

> +       ret = adxrs290_probe_trigger(indio_dev);
> +       if (ret < 0)
> +               return ret;

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/3] iio: gyro: adxrs290: Add triggered buffer support

[Nishant Malpani]

Hello,

Thanks for the review, Andy.

...

On Thu, Sep 3, 2020 at 6:50 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Sep 3, 2020 at 4:10 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
> >
> > Provide a way for continuous data capture by setting up buffer support. The
> > data ready signal exposed at the SYNC pin of the ADXRS290 is exploited as
> > a hardware interrupt which triggers to fill the buffer.
> >
> > Triggered buffer setup was tested with both hardware trigger (DATA_RDY) and
> > software triggers (sysfs-trig & hrtimer).
>
> ...
>
> > +static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
> > +{
> > +       struct adxrs290_state *st = iio_priv(indio_dev);
> > +       int val, ret;
> > +
> > +       if (st->mode == mode) {
>
> > +               ret = 0;
> > +               goto done;
>
> Unlocking the not locked mutex is not good. Have you followed the
> Submitting Patches Checklist? It in particular suggests few debug
> options, like LOCKDEP, to be enabled.
>

Yikes, silly me. Thanks for the suggestion. Will fix this in v3.

> > +       }
> > +
> > +       mutex_lock(&st->lock);
> > +
> > +       ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
> > +       if (ret < 0)
> > +               goto done;
> > +
> > +       val = ret;
> > +
> > +       switch (mode) {
> > +       case ADXRS290_MODE_STANDBY:
> > +               val &= ~ADXRS290_MEASUREMENT;
> > +               break;
> > +       case ADXRS290_MODE_MEASUREMENT:
> > +               val |= ADXRS290_MEASUREMENT;
> > +               break;
> > +       default:
> > +               ret = -EINVAL;
> > +               goto done;
> > +       }
> > +
> > +       ret = adxrs290_spi_write_reg(st->spi,
> > +                                    ADXRS290_REG_POWER_CTL,
> > +                                    val);
> > +       if (ret < 0) {
> > +               dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
> > +               goto done;
> > +       }
> > +
> > +       /* update cached mode */
> > +       st->mode = mode;
> > +
>
> > +done:
>
> Much better to call it out_unlock. It will help eliminate the mistakes
> like above.
>

Yes, makes sense.

> > +       mutex_unlock(&st->lock);
> > +       return ret;
> > +}
>
> ...
>
>
> What about
>
>   ret = -EINVAL;
>
> >         switch (mask) {
> >         case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> >                 lpf_idx = adxrs290_find_match(adxrs290_lpf_3db_freq_hz_table,
> >                                               ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table),
> >                                               val, val2);
> > -               if (lpf_idx < 0)
> > -                       return -EINVAL;
>
> > +               if (lpf_idx < 0) {
>
> > +                       ret = -EINVAL;
> > +                       break;
> > +               }
>
> Simple
>   break;
>
> and so on?
>

Umm, sure would save us a few lines but it seems to me like we are
trading off readability here. If no one agrees, will change it the way
you pointed out.

> > +
> >                 /* caching the updated state of the low-pass filter */
> >                 st->lpf_3db_freq_idx = lpf_idx;
> >                 /* retrieving the current state of the high-pass filter */
> >                 hpf_idx = st->hpf_3db_freq_idx;
> > -               return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> > +               ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> > +               break;
> > +
> >         case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> >                 hpf_idx = adxrs290_find_match(adxrs290_hpf_3db_freq_hz_table,
> >                                               ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table),
> >                                               val, val2);
> > -               if (hpf_idx < 0)
> > -                       return -EINVAL;
> > +               if (hpf_idx < 0) {
> > +                       ret = -EINVAL;
> > +                       break;
> > +               }
> > +
> >                 /* caching the updated state of the high-pass filter */
> >                 st->hpf_3db_freq_idx = hpf_idx;
> >                 /* retrieving the current state of the low-pass filter */
> >                 lpf_idx = st->lpf_3db_freq_idx;
> > -               return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> > +               ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> > +               break;
> > +
> > +       default:
> > +               ret = -EINVAL;
> > +               break;
> >         }
> >
> > -       return -EINVAL;
> > +       iio_device_release_direct_mode(indio_dev);
> > +       return ret;
> >  }
>
> ...
>
> > +static irqreturn_t adxrs290_trigger_handler(int irq, void *p)
> > +{
>
> > +       /* exercise a bulk data capture starting from reg DATAX0... */
> > +       ret = spi_write_then_read(st->spi, &tx, sizeof(tx), st->buffer.channels,
> > +                                 sizeof(st->buffer.channels));
> > +       if (ret < 0)
> > +               goto done;
> > +
> > +       iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
> > +                                          pf->timestamp);
> > +
> > +done:
>
> out_unlock_notify:
>

Okay.

> > +       mutex_unlock(&st->lock);
> > +       iio_trigger_notify_done(indio_dev->trig);
> > +
> > +       return IRQ_HANDLED;
> > +}
>
> ...
>
> > +static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
> > +{
> > +       struct adxrs290_state *st = iio_priv(indio_dev);
> > +       int ret;
>
> > +       if (!st->spi->irq) {
> > +               dev_info(&st->spi->dev, "no irq, using polling\n");
> > +               return 0;
> > +       }
>
> Wouldn't it be better to have this check outside of the function?

I think this function making an early exit makes more sense. The
CHIP_probe() looks less "noisy" that way.

> And taking this into account...
>
> > +}
>
> ...
>
> > +       ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> > +                                             &iio_pollfunc_store_time,
> > +                                             &adxrs290_trigger_handler, NULL);
> > +       if (ret < 0)
> > +               return dev_err_probe(&spi->dev, ret,
> > +                                    "iio triggered buffer setup failed\n");
>
> ...do you really have to set up a trigger buffer w/o trigger being probed?
>

I suppose one can use software triggers like hrtimer and sysfs-trig...

With regards,
Nishant Malpani

> > +       ret = adxrs290_probe_trigger(indio_dev);
> > +       if (ret < 0)
> > +               return ret;
>
> --
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v2 1/3] iio: gyro: adxrs290: Add triggered buffer support

[Jonathan Cameron]

On Thu,  3 Sep 2020 18:39:48 +0530
Nishant Malpani <nish.malpani25@gmail.com> wrote:

> Provide a way for continuous data capture by setting up buffer support. The
> data ready signal exposed at the SYNC pin of the ADXRS290 is exploited as
> a hardware interrupt which triggers to fill the buffer.
> 
> Triggered buffer setup was tested with both hardware trigger (DATA_RDY) and
> software triggers (sysfs-trig & hrtimer).
> 
> Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>
Hi Nishant,

A few additional comments

Jonathan

> ---
> 
> Changes in v2:
> 
>   - In adxrs290_set_mode(), move 'if' block outside the locked section
>   - use break statement for error handling instead of goto labels in
>     switch-case blocks
>   - remove outer parentheses when conditional ternary operator is used
>   - use dev_err_probe() saving a few lines of code
>   - re-align 'buffer' variable name in 'struct adxrs290_state'
>   - don't return errors in 'try_reenable' callback
>   - use 'st->spi' inline in 'adxrs290_trigger_handler'
>   - unnecessary to mention default 'shift' (= 0) in
>     iio_chan_spec.scan_type
>   - bring in consistent wrapping of parameters while staying under
>     the advised 80 chars line limit
> ---
>  drivers/iio/gyro/Kconfig    |   2 +
>  drivers/iio/gyro/adxrs290.c | 265 ++++++++++++++++++++++++++++++++++--
>  2 files changed, 253 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/iio/gyro/Kconfig b/drivers/iio/gyro/Kconfig
> index 024a34139875..5824f2edf975 100644
> --- a/drivers/iio/gyro/Kconfig
> +++ b/drivers/iio/gyro/Kconfig
> @@ -44,6 +44,8 @@ config ADIS16260
>  config ADXRS290
>  	tristate "Analog Devices ADXRS290 Dual-Axis MEMS Gyroscope SPI driver"
>  	depends on SPI
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
>  	help
>  	  Say yes here to build support for Analog Devices ADXRS290 programmable
>  	  digital output gyroscope.
> diff --git a/drivers/iio/gyro/adxrs290.c b/drivers/iio/gyro/adxrs290.c
> index ff989536d2fb..4099b8917d3e 100644
> --- a/drivers/iio/gyro/adxrs290.c
> +++ b/drivers/iio/gyro/adxrs290.c
> @@ -13,8 +13,12 @@
>  #include <linux/module.h>
>  #include <linux/spi/spi.h>
>  
> +#include <linux/iio/buffer.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger_consumer.h>
>  
>  #define ADXRS290_ADI_ID		0xAD
>  #define ADXRS290_MEMS_ID	0x1D
> @@ -35,7 +39,9 @@
>  #define ADXRS290_READ		BIT(7)
>  #define ADXRS290_TSM		BIT(0)
>  #define ADXRS290_MEASUREMENT	BIT(1)
> -#define ADXRS290_SYNC		GENMASK(1, 0)
> +#define ADXRS290_DATA_RDY_OUT	BIT(0)
> +#define ADXRS290_SYNC_MASK	GENMASK(1, 0)
> +#define ADXRS290_SYNC(x)	FIELD_PREP(ADXRS290_SYNC_MASK, x)
>  #define ADXRS290_LPF_MASK	GENMASK(2, 0)
>  #define ADXRS290_LPF(x)		FIELD_PREP(ADXRS290_LPF_MASK, x)
>  #define ADXRS290_HPF_MASK	GENMASK(7, 4)
> @@ -50,6 +56,13 @@ enum adxrs290_mode {
>  	ADXRS290_MODE_MEASUREMENT,
>  };
>  
> +enum adxrs290_scan_index {
> +	ADXRS290_IDX_X,
> +	ADXRS290_IDX_Y,
> +	ADXRS290_IDX_TEMP,
> +	ADXRS290_IDX_TS,
> +};
> +
>  struct adxrs290_state {
>  	struct spi_device	*spi;
>  	/* Serialize reads and their subsequent processing */
> @@ -57,6 +70,12 @@ struct adxrs290_state {
>  	enum adxrs290_mode	mode;
>  	unsigned int		lpf_3db_freq_idx;
>  	unsigned int		hpf_3db_freq_idx;
> +	struct iio_trigger      *dready_trig;
> +	/* Ensure correct alignment of timestamp when present */
> +	struct {
> +		s16 channels[3];
> +		s64 ts __aligned(8);
> +	} buffer;
>  };
>  
>  /*
> @@ -192,6 +211,52 @@ static int adxrs290_set_filter_freq(struct iio_dev *indio_dev,
>  	return adxrs290_spi_write_reg(st->spi, ADXRS290_REG_FILTER, val);
>  }
>  
> +static int adxrs290_set_mode(struct iio_dev *indio_dev, enum adxrs290_mode mode)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	int val, ret;
> +
> +	if (st->mode == mode) {
> +		ret = 0;
> +		goto done;
> +	}
> +
> +	mutex_lock(&st->lock);
> +
> +	ret = spi_w8r8(st->spi, ADXRS290_READ_REG(ADXRS290_REG_POWER_CTL));
> +	if (ret < 0)
> +		goto done;
> +
> +	val = ret;
> +
> +	switch (mode) {
> +	case ADXRS290_MODE_STANDBY:
> +		val &= ~ADXRS290_MEASUREMENT;
> +		break;
> +	case ADXRS290_MODE_MEASUREMENT:
> +		val |= ADXRS290_MEASUREMENT;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		goto done;
> +	}
> +
> +	ret = adxrs290_spi_write_reg(st->spi,
> +				     ADXRS290_REG_POWER_CTL,
> +				     val);
> +	if (ret < 0) {
> +		dev_err(&st->spi->dev, "unable to set mode: %d\n", ret);
> +		goto done;
> +	}
> +
> +	/* update cached mode */
> +	st->mode = mode;
> +
> +done:
> +	mutex_unlock(&st->lock);
> +	return ret;
> +}
> +
>  static int adxrs290_initial_setup(struct iio_dev *indio_dev)
>  {
>  	struct adxrs290_state *st = iio_priv(indio_dev);
> @@ -203,6 +268,13 @@ static int adxrs290_initial_setup(struct iio_dev *indio_dev)
>  				      ADXRS290_MEASUREMENT | ADXRS290_TSM);
>  }
>  
> +static void adxrs290_chip_off_action(void *data)
> +{
> +	struct iio_dev *indio_dev = data;
> +
> +	adxrs290_set_mode(indio_dev, ADXRS290_MODE_STANDBY);
> +}
> +
>  static int adxrs290_read_raw(struct iio_dev *indio_dev,
>  			     struct iio_chan_spec const *chan,
>  			     int *val,
> @@ -215,24 +287,34 @@ static int adxrs290_read_raw(struct iio_dev *indio_dev,
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +
>  		switch (chan->type) {
>  		case IIO_ANGL_VEL:
>  			ret = adxrs290_get_rate_data(indio_dev,
>  						     ADXRS290_READ_REG(chan->address),
>  						     val);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
> -			return IIO_VAL_INT;
> +			ret = IIO_VAL_INT;
> +			break;
>  		case IIO_TEMP:
>  			ret = adxrs290_get_temp_data(indio_dev, val);
>  			if (ret < 0)
> -				return ret;
> +				break;
>  
> -			return IIO_VAL_INT;
> +			ret = IIO_VAL_INT;
> +			break;
>  		default:
> -			return -EINVAL;
> +			ret = -EINVAL;
> +			break;
>  		}
> +
> +		iio_device_release_direct_mode(indio_dev);
> +		return ret;
>  	case IIO_CHAN_INFO_SCALE:
>  		switch (chan->type) {
>  		case IIO_ANGL_VEL:
> @@ -279,34 +361,52 @@ static int adxrs290_write_raw(struct iio_dev *indio_dev,
>  			      long mask)
>  {
>  	struct adxrs290_state *st = iio_priv(indio_dev);
> -	int lpf_idx, hpf_idx;
> +	int ret, lpf_idx, hpf_idx;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
>  		lpf_idx = adxrs290_find_match(adxrs290_lpf_3db_freq_hz_table,
>  					      ARRAY_SIZE(adxrs290_lpf_3db_freq_hz_table),
>  					      val, val2);
> -		if (lpf_idx < 0)
> -			return -EINVAL;
> +		if (lpf_idx < 0) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
>  		/* caching the updated state of the low-pass filter */
>  		st->lpf_3db_freq_idx = lpf_idx;
>  		/* retrieving the current state of the high-pass filter */
>  		hpf_idx = st->hpf_3db_freq_idx;
> -		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +		ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +		break;
> +
>  	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
>  		hpf_idx = adxrs290_find_match(adxrs290_hpf_3db_freq_hz_table,
>  					      ARRAY_SIZE(adxrs290_hpf_3db_freq_hz_table),
>  					      val, val2);
> -		if (hpf_idx < 0)
> -			return -EINVAL;
> +		if (hpf_idx < 0) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +
>  		/* caching the updated state of the high-pass filter */
>  		st->hpf_3db_freq_idx = hpf_idx;
>  		/* retrieving the current state of the low-pass filter */
>  		lpf_idx = st->lpf_3db_freq_idx;
> -		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +		ret = adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +		break;
> +
> +	default:
> +		ret = -EINVAL;
> +		break;
>  	}
>  
> -	return -EINVAL;
> +	iio_device_release_direct_mode(indio_dev);
> +	return ret;
>  }
>  
>  static int adxrs290_read_avail(struct iio_dev *indio_dev,
> @@ -334,6 +434,69 @@ static int adxrs290_read_avail(struct iio_dev *indio_dev,
>  	}
>  }
>  
> +static int adxrs290_data_rdy_trigger_set_state(struct iio_trigger *trig, bool state)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	int ret;
> +	u8 val;
> +
> +	val = state ? ADXRS290_SYNC(ADXRS290_DATA_RDY_OUT) : 0;
> +
> +	ret = adxrs290_spi_write_reg(st->spi, ADXRS290_REG_DATA_RDY, val);
> +	if (ret < 0)
> +		dev_err(&st->spi->dev, "failed to start data ready interrupt\n");
> +
> +	return ret;
> +}
> +
> +static int adxrs290_reset_trig(struct iio_trigger *trig)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	int val;
> +
> +	/*
> +	 * Data ready interrupt is reset after a read of the data registers.
> +	 * Here, we only read the 16b DATAY registers as that marks the end of
> +	 * a read of the data registers and initiates a reset for the interrupt line.
> +	 */
> +	adxrs290_get_rate_data(indio_dev, ADXRS290_READ_REG(ADXRS290_REG_DATAY0), &val);
> +
> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops adxrs290_trigger_ops = {
> +	.set_trigger_state = &adxrs290_data_rdy_trigger_set_state,
> +	.validate_device = &iio_trigger_validate_own_device,
> +	.try_reenable = &adxrs290_reset_trig,
> +};
> +
> +static irqreturn_t adxrs290_trigger_handler(int irq, void *p)
> +{
> +	struct iio_poll_func *pf = p;
> +	struct iio_dev *indio_dev = pf->indio_dev;
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	u8 tx = ADXRS290_READ_REG(ADXRS290_REG_DATAX0);
> +	int ret;
> +
> +	mutex_lock(&st->lock);
> +
> +	/* exercise a bulk data capture starting from reg DATAX0... */
> +	ret = spi_write_then_read(st->spi, &tx, sizeof(tx), st->buffer.channels,
> +				  sizeof(st->buffer.channels));
> +	if (ret < 0)
> +		goto done;
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
> +					   pf->timestamp);
> +
> +done:
> +	mutex_unlock(&st->lock);
> +	iio_trigger_notify_done(indio_dev->trig);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  #define ADXRS290_ANGL_VEL_CHANNEL(reg, axis) {				\
>  	.type = IIO_ANGL_VEL,						\
>  	.address = reg,							\
> @@ -346,6 +509,13 @@ static int adxrs290_read_avail(struct iio_dev *indio_dev,
>  	.info_mask_shared_by_type_available =				\
>  	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |		\
>  	BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),		\
> +	.scan_index = ADXRS290_IDX_##axis,				\
> +	.scan_type = {                                                  \
> +		.sign = 's',                                            \
> +		.realbits = 16,                                         \
> +		.storagebits = 16,                                      \
> +		.endianness = IIO_LE,					\
> +	},                                                              \
>  }
>  
>  static const struct iio_chan_spec adxrs290_channels[] = {
> @@ -356,7 +526,20 @@ static const struct iio_chan_spec adxrs290_channels[] = {
>  		.address = ADXRS290_REG_TEMP0,
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>  		BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = ADXRS290_IDX_TEMP,
> +		.scan_type = {
> +			.sign = 's',
> +			.realbits = 12,
> +			.storagebits = 16,
> +			.endianness = IIO_LE,
> +		},
>  	},
> +	IIO_CHAN_SOFT_TIMESTAMP(ADXRS290_IDX_TS),
> +};
> +
> +static const unsigned long adxrs290_avail_scan_masks[] = {
> +	BIT(ADXRS290_IDX_X) | BIT(ADXRS290_IDX_Y) | BIT(ADXRS290_IDX_TEMP),
> +	0
>  };
>  
>  static const struct iio_info adxrs290_info = {
> @@ -365,6 +548,43 @@ static const struct iio_info adxrs290_info = {
>  	.read_avail = &adxrs290_read_avail,
>  };
>  
> +static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (!st->spi->irq) {
> +		dev_info(&st->spi->dev, "no irq, using polling\n");
> +		return 0;
> +	}
> +
> +	st->dready_trig = devm_iio_trigger_alloc(&st->spi->dev, "%s-dev%d",
> +						 indio_dev->name,
> +						 indio_dev->id);
> +	if (!st->dready_trig)
> +		return -ENOMEM;
> +
> +	st->dready_trig->dev.parent = &st->spi->dev;
> +	st->dready_trig->ops = &adxrs290_trigger_ops;
> +	iio_trigger_set_drvdata(st->dready_trig, indio_dev);
> +
> +	ret = devm_request_irq(&st->spi->dev, st->spi->irq,
> +			       &iio_trigger_generic_data_rdy_poll,
> +			       IRQF_ONESHOT, "adxrs290_irq", st->dready_trig);
> +	if (ret < 0)
> +		return dev_err_probe(&st->spi->dev, ret,
> +				     "request irq %d failed\n", st->spi->irq);
> +
> +	ret = devm_iio_trigger_register(&st->spi->dev, st->dready_trig);
> +	if (ret)
> +		return dev_err_probe(&st->spi->dev, ret,

Only use dev_err_probe for calls that are requesting hardware resources
that may not yet be available.  The purpose is to handle deferred probing
neatly.  Here coming back later is unlikely to help as nothing will have
changed.

> +				     "iio trigger register failed\n");
> +
> +	indio_dev->trig = iio_trigger_get(st->dready_trig);
> +
> +	return 0;
> +}
> +
>  static int adxrs290_probe(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev;
> @@ -384,6 +604,7 @@ static int adxrs290_probe(struct spi_device *spi)
>  	indio_dev->channels = adxrs290_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(adxrs290_channels);
>  	indio_dev->info = &adxrs290_info;
> +	indio_dev->available_scan_masks = adxrs290_avail_scan_masks;
>  
>  	mutex_init(&st->lock);
>  
> @@ -416,6 +637,11 @@ static int adxrs290_probe(struct spi_device *spi)
>  	/* max transition time to measurement mode */
>  	msleep(ADXRS290_MAX_TRANSITION_TIME_MS);
>  
> +	ret = devm_add_action_or_reset(&spi->dev, adxrs290_chip_off_action,
> +				       indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
As per comment on v1 (sent just now :) I would move this into the init function.

I don't think it has anything to do with the rest of this patch, so pull it
out as a precursor change before the rest of the set.

>  	ret = adxrs290_get_3db_freq(indio_dev, &val, &val2);
>  	if (ret < 0)
>  		return ret;
> @@ -423,6 +649,17 @@ static int adxrs290_probe(struct spi_device *spi)
>  	st->lpf_3db_freq_idx = val;
>  	st->hpf_3db_freq_idx = val2;
>  
> +	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
> +					      &iio_pollfunc_store_time,
> +					      &adxrs290_trigger_handler, NULL);
> +	if (ret < 0)
> +		return dev_err_probe(&spi->dev, ret,
> +				     "iio triggered buffer setup failed\n");
> +
> +	ret = adxrs290_probe_trigger(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
>  	return devm_iio_device_register(&spi->dev, indio_dev);
>  }
>  

[PATCH v2 2/3] dt-bindings: iio: gyro: adxrs290: Add interrupts support

[Nishant Malpani]

Include 'interrupts' property and provide a suitable example for using
a GPIO interrupt line.

Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>
---

Changes in v2:

  - remove 'interrupts' property from the required properties list
  - rewrite commit message
---
 .../devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml b/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
index 61adb2c2454b..a5f209e8bbef 100644
--- a/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
+++ b/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
@@ -28,6 +28,9 @@ properties:
 
   spi-cpha: true
 
+  interrupts:
+    maxItems: 1
+
 required:
   - compatible
   - reg
@@ -39,6 +42,8 @@ additionalProperties: false
 
 examples:
   - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
     spi {
         #address-cells = <1>;
         #size-cells = <0>;
@@ -48,6 +53,8 @@ examples:
                    spi-max-frequency = <5000000>;
                    spi-cpol;
                    spi-cpha;
+                   interrupt-parent = <&gpio>;
+                   interrupts = <25 IRQ_TYPE_EDGE_RISING>;
         };
     };
 ...
-- 
2.20.1

Re: [PATCH v2 2/3] dt-bindings: iio: gyro: adxrs290: Add interrupts support

[Jonathan Cameron]

On Thu,  3 Sep 2020 18:39:49 +0530
Nishant Malpani <nish.malpani25@gmail.com> wrote:

> Include 'interrupts' property and provide a suitable example for using
> a GPIO interrupt line.
> 
> Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>

One little point inline.  Otherwise looks fine to me

Thanks,

Jonathan

> ---
> 
> Changes in v2:
> 
>   - remove 'interrupts' property from the required properties list
>   - rewrite commit message
> ---
>  .../devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml    | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml b/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
> index 61adb2c2454b..a5f209e8bbef 100644
> --- a/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
> +++ b/Documentation/devicetree/bindings/iio/gyroscope/adi,adxrs290.yaml
> @@ -28,6 +28,9 @@ properties:
>  
>    spi-cpha: true
>  
> +  interrupts:
> +    maxItems: 1
> +
>  required:
>    - compatible
>    - reg
> @@ -39,6 +42,8 @@ additionalProperties: false
>  
>  examples:
>    - |
> +    #include <dt-bindings/gpio/gpio.h>

Shouldn't need that header.  I don't see anything being used that
is defined in gpio.h

> +    #include <dt-bindings/interrupt-controller/irq.h>
>      spi {
>          #address-cells = <1>;
>          #size-cells = <0>;
> @@ -48,6 +53,8 @@ examples:
>                     spi-max-frequency = <5000000>;
>                     spi-cpol;
>                     spi-cpha;
> +                   interrupt-parent = <&gpio>;
> +                   interrupts = <25 IRQ_TYPE_EDGE_RISING>;
>          };
>      };
>  ...

[PATCH v2 3/3] iio: gyro: adxrs290: Add debugfs register access support

[Nishant Malpani]

Extend support to read/write byte data from/to the device using
debugfs iio interface.

Signed-off-by: Nishant Malpani <nish.malpani25@gmail.com>
---

No changes in v2
---
 drivers/iio/gyro/adxrs290.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/iio/gyro/adxrs290.c b/drivers/iio/gyro/adxrs290.c
index 4099b8917d3e..132fd16789f0 100644
--- a/drivers/iio/gyro/adxrs290.c
+++ b/drivers/iio/gyro/adxrs290.c
@@ -434,6 +434,24 @@ static int adxrs290_read_avail(struct iio_dev *indio_dev,
 	}
 }
 
+static int adxrs290_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+			       unsigned int writeval, unsigned int *readval)
+{
+	struct adxrs290_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!readval)
+		return adxrs290_spi_write_reg(st->spi, reg, writeval);
+
+	ret = spi_w8r8(st->spi, ADXRS290_READ_REG(reg));
+	if (ret < 0)
+		return ret;
+
+	*readval = ret;
+
+	return 0;
+}
+
 static int adxrs290_data_rdy_trigger_set_state(struct iio_trigger *trig, bool state)
 {
 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
@@ -546,6 +564,7 @@ static const struct iio_info adxrs290_info = {
 	.read_raw = &adxrs290_read_raw,
 	.write_raw = &adxrs290_write_raw,
 	.read_avail = &adxrs290_read_avail,
+	.debugfs_reg_access = &adxrs290_reg_access,
 };
 
 static int adxrs290_probe_trigger(struct iio_dev *indio_dev)
-- 
2.20.1

Re: [PATCH v2 3/3] iio: gyro: adxrs290: Add debugfs register access support

[Andy Shevchenko]

On Thu, Sep 3, 2020 at 4:10 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
>
> Extend support to read/write byte data from/to the device using
> debugfs iio interface.

...

> +static int adxrs290_reg_access(struct iio_dev *indio_dev, unsigned int reg,
> +                              unsigned int writeval, unsigned int *readval)
> +{
> +       struct adxrs290_state *st = iio_priv(indio_dev);
> +       int ret;
> +
> +       if (!readval)
> +               return adxrs290_spi_write_reg(st->spi, reg, writeval);
> +
> +       ret = spi_w8r8(st->spi, ADXRS290_READ_REG(reg));
> +       if (ret < 0)
> +               return ret;
> +
> +       *readval = ret;
> +
> +       return 0;
> +}

Hmm... I would suggest to have it like

adxrs290_reg_access_rw()
{
 ...
 return 0;
}

adxrs290_reg_access()
{
 if (readval)
  return adxrs290_reg_access_rw();
 else // it's redundant, but someone can use for better formatting
  return adxrs290_spi_write_reg();
}

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 3/3] iio: gyro: adxrs290: Add debugfs register access support

[Nishant Malpani]

Hello,

On Thu, Sep 3, 2020 at 6:55 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Sep 3, 2020 at 4:10 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
> >
> > Extend support to read/write byte data from/to the device using
> > debugfs iio interface.
>
> ...
>
> > +static int adxrs290_reg_access(struct iio_dev *indio_dev, unsigned int reg,
> > +                              unsigned int writeval, unsigned int *readval)
> > +{
> > +       struct adxrs290_state *st = iio_priv(indio_dev);
> > +       int ret;
> > +
> > +       if (!readval)
> > +               return adxrs290_spi_write_reg(st->spi, reg, writeval);
> > +
> > +       ret = spi_w8r8(st->spi, ADXRS290_READ_REG(reg));
> > +       if (ret < 0)
> > +               return ret;
> > +
> > +       *readval = ret;
> > +
> > +       return 0;
> > +}
>
> Hmm... I would suggest to have it like
>
> adxrs290_reg_access_rw()
> {
>  ...
>  return 0;
> }
>
> adxrs290_reg_access()
> {
>  if (readval)
>   return adxrs290_reg_access_rw();
>  else // it's redundant, but someone can use for better formatting
>   return adxrs290_spi_write_reg();
> }

Umm, I'm sorry, I don't see why'd it be favourable for us to do it
this way. Also, I *think* Jonathan is fine with how it's being done
now.

With regards,
Nishant Malpani

>
> --
> With Best Regards,
> Andy Shevchenko

Re: [PATCH v2 3/3] iio: gyro: adxrs290: Add debugfs register access support

[Andy Shevchenko]

On Thu, Sep 3, 2020 at 4:57 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
> On Thu, Sep 3, 2020 at 6:55 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:

...

> Umm, I'm sorry, I don't see why'd it be favourable for us to do it
> this way. Also, I *think* Jonathan is fine with how it's being done
> now.

I have no strong opinion, so whatever Jonathan thinks better.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 3/3] iio: gyro: adxrs290: Add debugfs register access support

[Jonathan Cameron]

On Thu, 3 Sep 2020 16:59:12 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Thu, Sep 3, 2020 at 4:57 PM Nishant Malpani <nish.malpani25@gmail.com> wrote:
> > On Thu, Sep 3, 2020 at 6:55 PM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:  
> 
> ...
> 
> > Umm, I'm sorry, I don't see why'd it be favourable for us to do it
> > this way. Also, I *think* Jonathan is fine with how it's being done
> > now.  
> 
> I have no strong opinion, so whatever Jonathan thinks better.
> 

Andy's suggestion is a little bit nicer, so as you are doing a v3,
might as well roll that change in as well :)

Jonathan