[PATCH 0/6] staging:iio:ad2s90: Add scale info and improve error handling

[PATCH 0/6] staging:iio:ad2s90: Add scale info and improve error handling

[Matheus Tavares]

This patch set adds scale info to ad2s90's single channel, improve
error handling in it's functions and fix a possible race condition
issue.

The goal with this patch set is to address the points discussed in the
mailing list in an effort to move ad2s90.c out of staging.

Matheus Tavares (5):
  staging:iio:ad2s90: Make read_raw return spi_read's error code
  staging:iio:ad2s90: Make probe handle spi_setup failure
  staging:iio:ad2s90: Remove always overwritten assignment
  staging:iio:ad2s90: Move device registration to the end of probe
  staging:iio:ad2s90: Check channel type at read_raw

Victor Colombo (1):
  staging:iio:ad2s90: Add IIO_CHAN_INFO_SCALE to channel spec and
    read_raw

 drivers/staging/iio/resolver/ad2s90.c | 55 ++++++++++++++++++---------
 1 file changed, 37 insertions(+), 18 deletions(-)

-- 
2.18.0

[PATCH 1/6] staging:iio:ad2s90: Make read_raw return spi_read's error code

[Matheus Tavares]

Previously, when spi_read returned an error code inside ad2s90_read_raw,
the code was ignored and IIO_VAL_INT was returned. This patch makes the
function return the error code returned by spi_read when it fails.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 drivers/staging/iio/resolver/ad2s90.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index 59586947a936..11fac9f90148 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -35,12 +35,15 @@ static int ad2s90_read_raw(struct iio_dev *indio_dev,
 	struct ad2s90_state *st = iio_priv(indio_dev);
 
 	mutex_lock(&st->lock);
+
 	ret = spi_read(st->sdev, st->rx, 2);
-	if (ret)
-		goto error_ret;
+	if (ret < 0) {
+		mutex_unlock(&st->lock);
+		return ret;
+	}
+
 	*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
 
-error_ret:
 	mutex_unlock(&st->lock);
 
 	return IIO_VAL_INT;
-- 
2.18.0

[PATCH 2/6] staging:iio:ad2s90: Make probe handle spi_setup failure

[Matheus Tavares]

Previously, ad2s90_probe ignored the return code from spi_setup, not
handling its possible failure. This patch makes ad2s90_probe check if
the code is an error code and, if so, do the following:

- Call dev_err with an appropriate error message.
- Return the spi_setup's error code, aborting the execution of the
rest of the function.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 drivers/staging/iio/resolver/ad2s90.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index 11fac9f90148..d6a42e3f1bd8 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -88,7 +88,12 @@ static int ad2s90_probe(struct spi_device *spi)
 	/* need 600ns between CS and the first falling edge of SCLK */
 	spi->max_speed_hz = 830000;
 	spi->mode = SPI_MODE_3;
-	spi_setup(spi);
+	ret = spi_setup(spi);
+
+	if (ret < 0) {
+		dev_err(&spi->dev, "spi_setup failed!\n");
+		return ret;
+	}
 
 	return 0;
 }
-- 
2.18.0

[PATCH 3/6] staging:iio:ad2s90: Remove always overwritten assignment

[Matheus Tavares]

This patch removes an initial assignment to the variable ret at probe,
that was always overwritten.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 drivers/staging/iio/resolver/ad2s90.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index d6a42e3f1bd8..c20d37dc065a 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -64,7 +64,7 @@ static int ad2s90_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
 	struct ad2s90_state *st;
-	int ret = 0;
+	int ret;
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 	if (!indio_dev)
-- 
2.18.0

[PATCH 4/6] staging:iio:ad2s90: Move device registration to the end of probe

[Matheus Tavares]

Previously, devm_iio_device_register was being called before the
spi_setup call and the spi_device's max_speed_hz and mode assignments.
This could lead to a race condition since the driver was still being
set up after it was already made ready to use. To fix it, this patch
moves the device registration to the end of ad2s90_probe.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 drivers/staging/iio/resolver/ad2s90.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index c20d37dc065a..b4a6a89c11b0 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -81,10 +81,6 @@ static int ad2s90_probe(struct spi_device *spi)
 	indio_dev->num_channels = 1;
 	indio_dev->name = spi_get_device_id(spi)->name;
 
-	ret = devm_iio_device_register(indio_dev->dev.parent, indio_dev);
-	if (ret)
-		return ret;
-
 	/* need 600ns between CS and the first falling edge of SCLK */
 	spi->max_speed_hz = 830000;
 	spi->mode = SPI_MODE_3;
@@ -95,7 +91,7 @@ static int ad2s90_probe(struct spi_device *spi)
 		return ret;
 	}
 
-	return 0;
+	return devm_iio_device_register(indio_dev->dev.parent, indio_dev);
 }
 
 static const struct spi_device_id ad2s90_id[] = {
-- 
2.18.0

[PATCH 5/6] staging:iio:ad2s90: Add IIO_CHAN_INFO_SCALE to channel spec and read_raw

[Matheus Tavares]

From: Victor Colombo <victorcolombo@gmail.com>

This patch adds the IIO_CHAN_INFO_SCALE mask to ad2s90_chan and
implements the relative read behavior at ad2s90_read_raw.

Signed-off-by: Victor Colombo <victorcolombo@gmail.com>
---
 drivers/staging/iio/resolver/ad2s90.c | 32 ++++++++++++++++++---------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index b4a6a89c11b0..52b656875ed1 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -34,19 +34,31 @@ static int ad2s90_read_raw(struct iio_dev *indio_dev,
 	int ret;
 	struct ad2s90_state *st = iio_priv(indio_dev);
 
-	mutex_lock(&st->lock);
+	switch (m) {
+	case IIO_CHAN_INFO_SCALE:
+		/* 2 * Pi / (2^12 - 1) ~= 0.001534355 */
+		*val = 0;
+		*val2 = 1534355;
+		return IIO_VAL_INT_PLUS_NANO;
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&st->lock);
+
+		ret = spi_read(st->sdev, st->rx, 2);
+		if (ret < 0) {
+			mutex_unlock(&st->lock);
+			return ret;
+		}
+
+		*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
 
-	ret = spi_read(st->sdev, st->rx, 2);
-	if (ret < 0) {
 		mutex_unlock(&st->lock);
-		return ret;
-	}
 
-	*val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
-
-	mutex_unlock(&st->lock);
+		return IIO_VAL_INT;
+	default:
+		break;
+	}
 
-	return IIO_VAL_INT;
+	return -EINVAL;
 }
 
 static const struct iio_info ad2s90_info = {
@@ -57,7 +69,7 @@ static const struct iio_chan_spec ad2s90_chan = {
 	.type = IIO_ANGL,
 	.indexed = 1,
 	.channel = 0,
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 };
 
 static int ad2s90_probe(struct spi_device *spi)
-- 
2.18.0

[PATCH 6/6] staging:iio:ad2s90: Check channel type at read_raw

[Matheus Tavares]

This patch adds a channel type check at the beginning of the
ad2s90_read_raw function. Since ad2s90 has only one channel, it just
checks if the given channel is the expected one and if not, return
-EINVAL.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 drivers/staging/iio/resolver/ad2s90.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/iio/resolver/ad2s90.c b/drivers/staging/iio/resolver/ad2s90.c
index 52b656875ed1..24002042a5c5 100644
--- a/drivers/staging/iio/resolver/ad2s90.c
+++ b/drivers/staging/iio/resolver/ad2s90.c
@@ -34,6 +34,9 @@ static int ad2s90_read_raw(struct iio_dev *indio_dev,
 	int ret;
 	struct ad2s90_state *st = iio_priv(indio_dev);
 
+	if (chan->type != IIO_ANGL)
+		return -EINVAL;
+
 	switch (m) {
 	case IIO_CHAN_INFO_SCALE:
 		/* 2 * Pi / (2^12 - 1) ~= 0.001534355 */
-- 
2.18.0

Re: [PATCH 5/6] staging:iio:ad2s90: Add IIO_CHAN_INFO_SCALE to channel spec and read_raw

[Dan Carpenter]

On Thu, Oct 25, 2018 at 09:45:11PM -0300, Matheus Tavares wrote:
> From: Victor Colombo <victorcolombo@gmail.com>
> 
> This patch adds the IIO_CHAN_INFO_SCALE mask to ad2s90_chan and
> implements the relative read behavior at ad2s90_read_raw.
> 
> Signed-off-by: Victor Colombo <victorcolombo@gmail.com>
> ---

You should be adding your S-o-B here as well because the patch is
passing through your hands.

regards,
dan carpenter

Re: [PATCH 5/6] staging:iio:ad2s90: Add IIO_CHAN_INFO_SCALE to channel spec and read_raw

[Matheus Tavares Bernardino]

On Fri, Oct 26, 2018 at 7:04 AM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Thu, Oct 25, 2018 at 09:45:11PM -0300, Matheus Tavares wrote:
> > From: Victor Colombo <victorcolombo@gmail.com>
> >
> > This patch adds the IIO_CHAN_INFO_SCALE mask to ad2s90_chan and
> > implements the relative read behavior at ad2s90_read_raw.
> >
> > Signed-off-by: Victor Colombo <victorcolombo@gmail.com>
> > ---
>
> You should be adding your S-o-B here as well because the patch is
> passing through your hands.

Thanks for the review! I'll be sending a v2 with my S-o-B there.

> regards,
> dan carpenter
>
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