[PATCH 0/2] meson-saradc: preparations for temperature sensor support

[PATCH 0/2] meson-saradc: preparations for temperature sensor support

[Martin Blumenstingl]

This is a follow-up of my previous series "meson-saradc: small code
improvements" from [0].

I broke these smaller patches out of my big "add support for the chip's
temperature sensor" patch to make that easier to review. That patch
will also depend on a change to the clock controller's dt-bindings on
Meson8, Meson8b and Meson8m2 - see my patch "dt-bindings: clock:
meson8b: use the registers from the HHI syscon" from [1].

I can also post an RFC version of the actual temperature sensor patches
if it makes the code-review of these smaller ones easier (so you see
the "big picture").


Regards
Martin


[0] https://www.spinics.net/lists/linux-iio/msg40632.html
[1] https://patchwork.kernel.org/patch/10539027/

Martin Blumenstingl (2):
  iio: adc: meson-saradc: do not use meson_sar_adc_iio_channels directly
  iio: adc: meson-saradc: use the address attribute from iio_chan_spec

 drivers/iio/adc/meson_saradc.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

-- 
2.19.0

[PATCH 1/2] iio: adc: meson-saradc: do not use meson_sar_adc_iio_channels directly

[Martin Blumenstingl]

In the future we may support two different channel sets:
- one which includes the voltage pads and the temperature sensor output
  (for Meson8, Meson8b and Meson8m2)
- one which only includes the voltage pads (GXBB, GXL, GXM and AXG)

Channel 7 has a special function on all of these platforms. However,
since we will have different channel array definitions we want our code
to always use whatever channels struct iio_dev uses.

No functional changes for now. This is the preparation for adding
temperature sensor support to this driver.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/iio/adc/meson_saradc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 1c4ba83c0725..809d1230be34 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -854,7 +854,7 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
 	meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
 	usleep_range(10, 20);
 	ret = meson_sar_adc_get_sample(indio_dev,
-				       &meson_sar_adc_iio_channels[7],
+				       &indio_dev->channels[7],
 				       MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
 	if (ret < 0)
 		goto out;
@@ -862,7 +862,7 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
 	meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
 	usleep_range(10, 20);
 	ret = meson_sar_adc_get_sample(indio_dev,
-				       &meson_sar_adc_iio_channels[7],
+				       &indio_dev->channels[7],
 				       MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
 	if (ret < 0)
 		goto out;
-- 
2.19.0

[PATCH 2/2] iio: adc: meson-saradc: use the address attribute from iio_chan_spec

[Martin Blumenstingl]

Until now the "channel" number is identical to how the channel is
identified inside the (FIFO) registers. In our case we have eight
channels and the hardware also has eight inputs.

However, there are two special inputs:
- channel 6 can select between the SAR_ADC_CH6 pad and the chip's
  internal temperature sensor
- channel 7 can select between SAR_ADC_CH7 and VSS, VDD / 4, VDD / 2,
  VDD * 3 / 4 and VDD.

When programming the registers to read for example the temperature
sensor we have to select FIFO channel 6, set the correct bit which muxes
channel 6 to the temperature sensor and then start the ADC measurement
for channel 6 as usual.

When we add support for the temperature sensor the driver has to know
about that it has to use FIFO channel 6 to measure using the chip's
internal temperature sensor. However, in that case the iio_chan_spec
channel will not be 6 because this is already used for the SAR_ADC_CH6
pad input. Thus we use iio_chan_spec's address field to store the FIFO
channel number for each channel.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
---
 drivers/iio/adc/meson_saradc.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 809d1230be34..028ccd218f82 100644
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -172,6 +172,7 @@
 	.type = IIO_VOLTAGE,						\
 	.indexed = 1,							\
 	.channel = _chan,						\
+	.address = _chan,						\
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
 				BIT(IIO_CHAN_INFO_AVERAGE_RAW),		\
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
@@ -323,10 +324,10 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
 
 	regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, &regval);
 	fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval);
-	if (fifo_chan != chan->channel) {
+	if (fifo_chan != chan->address) {
 		dev_err(&indio_dev->dev,
-			"ADC FIFO entry belongs to channel %d instead of %d\n",
-			fifo_chan, chan->channel);
+			"ADC FIFO entry belongs to channel %d instead of %lu\n",
+			fifo_chan, chan->address);
 		return -EINVAL;
 	}
 
@@ -343,16 +344,16 @@ static void meson_sar_adc_set_averaging(struct iio_dev *indio_dev,
 					enum meson_sar_adc_num_samples samples)
 {
 	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
-	int val, channel = chan->channel;
+	int val, address = chan->address;
 
-	val = samples << MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(channel);
+	val = samples << MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(address);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
-			   MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(channel),
+			   MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(address),
 			   val);
 
-	val = mode << MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(channel);
+	val = mode << MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(address);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
-			   MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(channel), val);
+			   MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(address), val);
 }
 
 static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
@@ -372,23 +373,23 @@ static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
 
 	/* map channel index 0 to the channel which we want to read */
 	regval = FIELD_PREP(MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0),
-			    chan->channel);
+			    chan->address);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_CHAN_LIST,
 			   MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0), regval);
 
 	regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
-			    chan->channel);
+			    chan->address);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
 			   MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
 			   regval);
 
 	regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
-			    chan->channel);
+			    chan->address);
 	regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
 			   MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
 			   regval);
 
-	if (chan->channel == 6)
+	if (chan->address == 6)
 		regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELTA_10,
 				   MESON_SAR_ADC_DELTA_10_TEMP_SEL, 0);
 }
@@ -526,8 +527,8 @@ static int meson_sar_adc_get_sample(struct iio_dev *indio_dev,
 
 	if (ret) {
 		dev_warn(indio_dev->dev.parent,
-			 "failed to read sample for channel %d: %d\n",
-			 chan->channel, ret);
+			 "failed to read sample for channel %lu: %d\n",
+			 chan->address, ret);
 		return ret;
 	}
 
-- 
2.19.0

[PATCH 1/2] iio: adc: meson-saradc: do not use meson_sar_adc_iio_channels directly

[Jonathan Cameron]

On Tue, 25 Sep 2018 00:13:25 +0200
Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

> In the future we may support two different channel sets:
> - one which includes the voltage pads and the temperature sensor output
>   (for Meson8, Meson8b and Meson8m2)
> - one which only includes the voltage pads (GXBB, GXL, GXM and AXG)
> 
> Channel 7 has a special function on all of these platforms. However,
> since we will have different channel array definitions we want our code
> to always use whatever channels struct iio_dev uses.
> 
> No functional changes for now. This is the preparation for adding
> temperature sensor support to this driver.
> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Straight forward and 'obviously' correct.

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/meson_saradc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 1c4ba83c0725..809d1230be34 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -854,7 +854,7 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
>  	meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_DIV4);
>  	usleep_range(10, 20);
>  	ret = meson_sar_adc_get_sample(indio_dev,
> -				       &meson_sar_adc_iio_channels[7],
> +				       &indio_dev->channels[7],
>  				       MEAN_AVERAGING, EIGHT_SAMPLES, &value0);
>  	if (ret < 0)
>  		goto out;
> @@ -862,7 +862,7 @@ static int meson_sar_adc_calib(struct iio_dev *indio_dev)
>  	meson_sar_adc_set_chan7_mux(indio_dev, CHAN7_MUX_VDD_MUL3_DIV4);
>  	usleep_range(10, 20);
>  	ret = meson_sar_adc_get_sample(indio_dev,
> -				       &meson_sar_adc_iio_channels[7],
> +				       &indio_dev->channels[7],
>  				       MEAN_AVERAGING, EIGHT_SAMPLES, &value1);
>  	if (ret < 0)
>  		goto out;

[PATCH 2/2] iio: adc: meson-saradc: use the address attribute from iio_chan_spec

[Jonathan Cameron]

On Tue, 25 Sep 2018 00:13:26 +0200
Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

> Until now the "channel" number is identical to how the channel is
> identified inside the (FIFO) registers. In our case we have eight
> channels and the hardware also has eight inputs.
> 
> However, there are two special inputs:
> - channel 6 can select between the SAR_ADC_CH6 pad and the chip's
>   internal temperature sensor
> - channel 7 can select between SAR_ADC_CH7 and VSS, VDD / 4, VDD / 2,
>   VDD * 3 / 4 and VDD.
> 
> When programming the registers to read for example the temperature
> sensor we have to select FIFO channel 6, set the correct bit which muxes
> channel 6 to the temperature sensor and then start the ADC measurement
> for channel 6 as usual.
> 
> When we add support for the temperature sensor the driver has to know
> about that it has to use FIFO channel 6 to measure using the chip's
> internal temperature sensor. However, in that case the iio_chan_spec
> channel will not be 6 because this is already used for the SAR_ADC_CH6
> pad input. Thus we use iio_chan_spec's address field to store the FIFO
> channel number for each channel.
> 
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Again, clearly 'correct' so applied to the togreg branch of iio.git
and pushed out as testing for the autobuilders to play with it.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/meson_saradc.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 809d1230be34..028ccd218f82 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -172,6 +172,7 @@
>  	.type = IIO_VOLTAGE,						\
>  	.indexed = 1,							\
>  	.channel = _chan,						\
> +	.address = _chan,						\
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
>  				BIT(IIO_CHAN_INFO_AVERAGE_RAW),		\
>  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
> @@ -323,10 +324,10 @@ static int meson_sar_adc_read_raw_sample(struct iio_dev *indio_dev,
>  
>  	regmap_read(priv->regmap, MESON_SAR_ADC_FIFO_RD, &regval);
>  	fifo_chan = FIELD_GET(MESON_SAR_ADC_FIFO_RD_CHAN_ID_MASK, regval);
> -	if (fifo_chan != chan->channel) {
> +	if (fifo_chan != chan->address) {
>  		dev_err(&indio_dev->dev,
> -			"ADC FIFO entry belongs to channel %d instead of %d\n",
> -			fifo_chan, chan->channel);
> +			"ADC FIFO entry belongs to channel %d instead of %lu\n",
> +			fifo_chan, chan->address);
>  		return -EINVAL;
>  	}
>  
> @@ -343,16 +344,16 @@ static void meson_sar_adc_set_averaging(struct iio_dev *indio_dev,
>  					enum meson_sar_adc_num_samples samples)
>  {
>  	struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> -	int val, channel = chan->channel;
> +	int val, address = chan->address;
>  
> -	val = samples << MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(channel);
> +	val = samples << MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_SHIFT(address);
>  	regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
> -			   MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(channel),
> +			   MESON_SAR_ADC_AVG_CNTL_NUM_SAMPLES_MASK(address),
>  			   val);
>  
> -	val = mode << MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(channel);
> +	val = mode << MESON_SAR_ADC_AVG_CNTL_AVG_MODE_SHIFT(address);
>  	regmap_update_bits(priv->regmap, MESON_SAR_ADC_AVG_CNTL,
> -			   MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(channel), val);
> +			   MESON_SAR_ADC_AVG_CNTL_AVG_MODE_MASK(address), val);
>  }
>  
>  static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
> @@ -372,23 +373,23 @@ static void meson_sar_adc_enable_channel(struct iio_dev *indio_dev,
>  
>  	/* map channel index 0 to the channel which we want to read */
>  	regval = FIELD_PREP(MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0),
> -			    chan->channel);
> +			    chan->address);
>  	regmap_update_bits(priv->regmap, MESON_SAR_ADC_CHAN_LIST,
>  			   MESON_SAR_ADC_CHAN_LIST_ENTRY_MASK(0), regval);
>  
>  	regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
> -			    chan->channel);
> +			    chan->address);
>  	regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
>  			   MESON_SAR_ADC_DETECT_IDLE_SW_DETECT_MUX_MASK,
>  			   regval);
>  
>  	regval = FIELD_PREP(MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
> -			    chan->channel);
> +			    chan->address);
>  	regmap_update_bits(priv->regmap, MESON_SAR_ADC_DETECT_IDLE_SW,
>  			   MESON_SAR_ADC_DETECT_IDLE_SW_IDLE_MUX_SEL_MASK,
>  			   regval);
>  
> -	if (chan->channel == 6)
> +	if (chan->address == 6)
>  		regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELTA_10,
>  				   MESON_SAR_ADC_DELTA_10_TEMP_SEL, 0);
>  }
> @@ -526,8 +527,8 @@ static int meson_sar_adc_get_sample(struct iio_dev *indio_dev,
>  
>  	if (ret) {
>  		dev_warn(indio_dev->dev.parent,
> -			 "failed to read sample for channel %d: %d\n",
> -			 chan->channel, ret);
> +			 "failed to read sample for channel %lu: %d\n",
> +			 chan->address, ret);
>  		return ret;
>  	}
>