diff mbox series

[1/2] iio: adc: sc27xx: Add raw data support

Message ID 4a7e33457617e6f0f7c9627fe20ddd3039e4fe82.1535103920.git.baolin.wang@linaro.org
State Accepted
Commit fd2f53ebf98173d667fe6b9c2300fef8b4f72f30
Headers show
Series [1/2] iio: adc: sc27xx: Add raw data support | expand

Commit Message

(Exiting) Baolin Wang Aug. 24, 2018, 9:53 a.m. UTC 
The headset device will use channel 20 of ADC controller to detect events,
but it needs the raw ADC data to do conversion according to its own formula.

Thus we should configure the channel mask separately and configure channel
20 as IIO_CHAN_INFO_RAW, as well as adding raw data read support.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
 drivers/iio/adc/sc27xx_adc.c |   80 ++++++++++++++++++++++++------------------
 1 file changed, 45 insertions(+), 35 deletions(-)

-- 
1.7.9.5

Comments

Jonathan Cameron Aug. 25, 2018, 8:38 a.m. UTC | #1 
On Fri, 24 Aug 2018 17:53:15 +0800
Baolin Wang <baolin.wang@linaro.org> wrote:

> The headset device will use channel 20 of ADC controller to detect events,

> but it needs the raw ADC data to do conversion according to its own formula.

> 

> Thus we should configure the channel mask separately and configure channel

> 20 as IIO_CHAN_INFO_RAW, as well as adding raw data read support.


So is this a general thing, i.e. that channel is 'meant' to be used for the
headset, or just a one off for a particular board?

If it is a general thing, than I'm fine with this (unlikely we'll break any
other users), but if not we need to find a nicer way to do it.
I am a little unclear on how a channel would provide the voltage on it's pin
but that could be wrong when used for a different purpose?
If it's just a matter of unusual loading characteristics then perhaps that
is valid, but I'd like to understand this a little.

> 

> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

> ---

>  drivers/iio/adc/sc27xx_adc.c |   80 ++++++++++++++++++++++++------------------

>  1 file changed, 45 insertions(+), 35 deletions(-)

> 

> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c

> index 2b60efe..153c311 100644

> --- a/drivers/iio/adc/sc27xx_adc.c

> +++ b/drivers/iio/adc/sc27xx_adc.c

> @@ -273,6 +273,17 @@ static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,

>  	int ret, tmp;

>  

>  	switch (mask) {

> +	case IIO_CHAN_INFO_RAW:

> +		mutex_lock(&indio_dev->mlock);

> +		ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);

> +		mutex_unlock(&indio_dev->mlock);

> +

> +		if (ret)

> +			return ret;

> +

> +		*val = tmp;

> +		return IIO_VAL_INT;

> +

>  	case IIO_CHAN_INFO_PROCESSED:

>  		mutex_lock(&indio_dev->mlock);

>  		ret = sc27xx_adc_read_processed(data, chan->channel, scale,

> @@ -315,48 +326,47 @@ static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,

>  	.write_raw = &sc27xx_adc_write_raw,

>  };

>  

> -#define SC27XX_ADC_CHANNEL(index) {				\

> +#define SC27XX_ADC_CHANNEL(index, mask) {			\

>  	.type = IIO_VOLTAGE,					\

>  	.channel = index,					\

> -	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |	\

> -			      BIT(IIO_CHAN_INFO_SCALE),		\

> +	.info_mask_separate = mask | BIT(IIO_CHAN_INFO_SCALE),	\

>  	.datasheet_name = "CH##index",				\

>  	.indexed = 1,						\

>  }

>  

>  static const struct iio_chan_spec sc27xx_channels[] = {

> -	SC27XX_ADC_CHANNEL(0),

> -	SC27XX_ADC_CHANNEL(1),

> -	SC27XX_ADC_CHANNEL(2),

> -	SC27XX_ADC_CHANNEL(3),

> -	SC27XX_ADC_CHANNEL(4),

> -	SC27XX_ADC_CHANNEL(5),

> -	SC27XX_ADC_CHANNEL(6),

> -	SC27XX_ADC_CHANNEL(7),

> -	SC27XX_ADC_CHANNEL(8),

> -	SC27XX_ADC_CHANNEL(9),

> -	SC27XX_ADC_CHANNEL(10),

> -	SC27XX_ADC_CHANNEL(11),

> -	SC27XX_ADC_CHANNEL(12),

> -	SC27XX_ADC_CHANNEL(13),

> -	SC27XX_ADC_CHANNEL(14),

> -	SC27XX_ADC_CHANNEL(15),

> -	SC27XX_ADC_CHANNEL(16),

> -	SC27XX_ADC_CHANNEL(17),

> -	SC27XX_ADC_CHANNEL(18),

> -	SC27XX_ADC_CHANNEL(19),

> -	SC27XX_ADC_CHANNEL(20),

> -	SC27XX_ADC_CHANNEL(21),

> -	SC27XX_ADC_CHANNEL(22),

> -	SC27XX_ADC_CHANNEL(23),

> -	SC27XX_ADC_CHANNEL(24),

> -	SC27XX_ADC_CHANNEL(25),

> -	SC27XX_ADC_CHANNEL(26),

> -	SC27XX_ADC_CHANNEL(27),

> -	SC27XX_ADC_CHANNEL(28),

> -	SC27XX_ADC_CHANNEL(29),

> -	SC27XX_ADC_CHANNEL(30),

> -	SC27XX_ADC_CHANNEL(31),

> +	SC27XX_ADC_CHANNEL(0, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(1, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(2, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(3, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(4, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(5, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(6, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(7, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(8, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(9, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(10, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(11, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(12, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(13, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(14, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(15, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(16, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(17, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(18, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(19, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(20, BIT(IIO_CHAN_INFO_RAW)),

> +	SC27XX_ADC_CHANNEL(21, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(22, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(23, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(24, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(25, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(26, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(27, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(28, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(29, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(30, BIT(IIO_CHAN_INFO_PROCESSED)),

> +	SC27XX_ADC_CHANNEL(31, BIT(IIO_CHAN_INFO_PROCESSED)),

>  };

>  

>  static int sc27xx_adc_enable(struct sc27xx_adc_data *data)
Jonathan Cameron Aug. 25, 2018, 8:43 a.m. UTC | #2 
On Fri, 24 Aug 2018 17:53:16 +0800
Baolin Wang <baolin.wang@linaro.org> wrote:

> This patch adds support to read calibration values from the eFuse

> controller to calibrate the ADC channel scales, which can make ADC

> sample data more accurate.

> 

> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

This looks good to me.  I'll leave it for now though given open questions
on patch 1 and to allow others time to comment on this if they wish -
particularly as it includes a binding addition.

Jonathan

> ---

>  .../bindings/iio/adc/sprd,sc27xx-adc.txt           |    4 ++

>  drivers/iio/adc/sc27xx_adc.c                       |   52 ++++++++++++++++++--

>  2 files changed, 53 insertions(+), 3 deletions(-)

> 

> diff --git a/Documentation/devicetree/bindings/iio/adc/sprd,sc27xx-adc.txt b/Documentation/devicetree/bindings/iio/adc/sprd,sc27xx-adc.txt

> index 8aad960..b4daa15 100644

> --- a/Documentation/devicetree/bindings/iio/adc/sprd,sc27xx-adc.txt

> +++ b/Documentation/devicetree/bindings/iio/adc/sprd,sc27xx-adc.txt

> @@ -12,6 +12,8 @@ Required properties:

>  - interrupts: The interrupt number for the ADC device.

>  - #io-channel-cells: Number of cells in an IIO specifier.

>  - hwlocks: Reference to a phandle of a hwlock provider node.

> +- nvmem-cells: A phandle to the calibration cells provided by eFuse device.

> +- nvmem-cell-names: Should be "big_scale_calib", "small_scale_calib".

>  

>  Example:

>  

> @@ -32,5 +34,7 @@ Example:

>  			interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;

>  			#io-channel-cells = <1>;

>  			hwlocks = <&hwlock 4>;

> +			nvmem-cells = <&adc_big_scale>, <&adc_small_scale>;

> +			nvmem-cell-names = "big_scale_calib", "small_scale_calib";

>  		};

>  	};

> diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c

> index 153c311..7ac78eda 100644

> --- a/drivers/iio/adc/sc27xx_adc.c

> +++ b/drivers/iio/adc/sc27xx_adc.c

> @@ -5,6 +5,7 @@

>  #include <linux/iio/iio.h>

>  #include <linux/interrupt.h>

>  #include <linux/module.h>

> +#include <linux/nvmem-consumer.h>

>  #include <linux/of.h>

>  #include <linux/of_device.h>

>  #include <linux/platform_device.h>

> @@ -87,16 +88,48 @@ struct sc27xx_adc_linear_graph {

>   * should use the small-scale graph, and if more than 1.2v, we should use the

>   * big-scale graph.

>   */

> -static const struct sc27xx_adc_linear_graph big_scale_graph = {

> +static struct sc27xx_adc_linear_graph big_scale_graph = {

>  	4200, 3310,

>  	3600, 2832,

>  };

>  

> -static const struct sc27xx_adc_linear_graph small_scale_graph = {

> +static struct sc27xx_adc_linear_graph small_scale_graph = {

>  	1000, 3413,

>  	100, 341,

>  };

>  

> +static const struct sc27xx_adc_linear_graph big_scale_graph_calib = {

> +	4200, 856,

> +	3600, 733,

> +};

> +

> +static const struct sc27xx_adc_linear_graph small_scale_graph_calib = {

> +	1000, 833,

> +	100, 80,

> +};

> +

> +static int sc27xx_adc_get_calib_data(u32 calib_data, int calib_adc)

> +{

> +	return ((calib_data & 0xff) + calib_adc - 128) * 4;

> +}

> +

> +static void

> +sc27xx_adc_scale_calibration(const struct sc27xx_adc_linear_graph *calib_graph,

> +			     u32 calib_data, bool big_scale)

> +{

> +	struct sc27xx_adc_linear_graph *graph;

> +

> +	if (big_scale)

> +		graph = &big_scale_graph;

> +	else

> +		graph = &small_scale_graph;

> +

> +	/* Only need to calibrate the adc values in the linear graph. */

> +	graph->adc0 = sc27xx_adc_get_calib_data(calib_data, calib_graph->adc0);

> +	graph->adc1 = sc27xx_adc_get_calib_data(calib_data >> 8,

> +						calib_graph->adc1);

> +}

> +

>  static int sc27xx_adc_get_ratio(int channel, int scale)

>  {

>  	switch (channel) {

> @@ -209,7 +242,7 @@ static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data,

>  	*div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK;

>  }

>  

> -static int sc27xx_adc_to_volt(const struct sc27xx_adc_linear_graph *graph,

> +static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,

>  			      int raw_adc)

>  {

>  	int tmp;

> @@ -371,6 +404,7 @@ static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,

>  

>  static int sc27xx_adc_enable(struct sc27xx_adc_data *data)

>  {

> +	u32 val;

>  	int ret;

>  

>  	ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN,

> @@ -390,6 +424,18 @@ static int sc27xx_adc_enable(struct sc27xx_adc_data *data)

>  	if (ret)

>  		goto disable_clk;

>  

> +	/* ADC channel scales' calibration from nvmem device */

> +	ret = nvmem_cell_read_u32(data->dev, "big_scale_calib", &val);

> +	if (ret)

> +		goto disable_clk;

> +

> +	sc27xx_adc_scale_calibration(&big_scale_graph_calib, val, true);

> +

> +	ret = nvmem_cell_read_u32(data->dev, "small_scale_calib", &val);

> +	if (ret)

> +		goto disable_clk;

> +

> +	sc27xx_adc_scale_calibration(&small_scale_graph_calib, val, false);

>  	return 0;

>  

>  disable_clk:
(Exiting) Baolin Wang Aug. 28, 2018, 3:20 a.m. UTC | #3 
Hi Jonathan,

On 25 August 2018 at 16:43, Jonathan Cameron <jic23@kernel.org> wrote:
> On Fri, 24 Aug 2018 17:53:16 +0800

> Baolin Wang <baolin.wang@linaro.org> wrote:

>

>> This patch adds support to read calibration values from the eFuse

>> controller to calibrate the ADC channel scales, which can make ADC

>> sample data more accurate.

>>

>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

> This looks good to me.  I'll leave it for now though given open questions

> on patch 1 and to allow others time to comment on this if they wish -

> particularly as it includes a binding addition.


Thanks for your reviewing. But after more testing, we found one issue
when reading calibration data from efuse, which is not always 4 bytes
(sizeof(u32)). So I will change to use nvmem_cell_read() instead of
nvmem_cell_read_u32() in next version.

-- 
Baolin Wang
Best Regards
diff mbox series

Patch

diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c
index 2b60efe..153c311 100644
--- a/drivers/iio/adc/sc27xx_adc.c
+++ b/drivers/iio/adc/sc27xx_adc.c
@@ -273,6 +273,17 @@  static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
 	int ret, tmp;
 
 	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&indio_dev->mlock);
+		ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
+		mutex_unlock(&indio_dev->mlock);
+
+		if (ret)
+			return ret;
+
+		*val = tmp;
+		return IIO_VAL_INT;
+
 	case IIO_CHAN_INFO_PROCESSED:
 		mutex_lock(&indio_dev->mlock);
 		ret = sc27xx_adc_read_processed(data, chan->channel, scale,
@@ -315,48 +326,47 @@  static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,
 	.write_raw = &sc27xx_adc_write_raw,
 };
 
-#define SC27XX_ADC_CHANNEL(index) {				\
+#define SC27XX_ADC_CHANNEL(index, mask) {			\
 	.type = IIO_VOLTAGE,					\
 	.channel = index,					\
-	.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |	\
-			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.info_mask_separate = mask | BIT(IIO_CHAN_INFO_SCALE),	\
 	.datasheet_name = "CH##index",				\
 	.indexed = 1,						\
 }
 
 static const struct iio_chan_spec sc27xx_channels[] = {
-	SC27XX_ADC_CHANNEL(0),
-	SC27XX_ADC_CHANNEL(1),
-	SC27XX_ADC_CHANNEL(2),
-	SC27XX_ADC_CHANNEL(3),
-	SC27XX_ADC_CHANNEL(4),
-	SC27XX_ADC_CHANNEL(5),
-	SC27XX_ADC_CHANNEL(6),
-	SC27XX_ADC_CHANNEL(7),
-	SC27XX_ADC_CHANNEL(8),
-	SC27XX_ADC_CHANNEL(9),
-	SC27XX_ADC_CHANNEL(10),
-	SC27XX_ADC_CHANNEL(11),
-	SC27XX_ADC_CHANNEL(12),
-	SC27XX_ADC_CHANNEL(13),
-	SC27XX_ADC_CHANNEL(14),
-	SC27XX_ADC_CHANNEL(15),
-	SC27XX_ADC_CHANNEL(16),
-	SC27XX_ADC_CHANNEL(17),
-	SC27XX_ADC_CHANNEL(18),
-	SC27XX_ADC_CHANNEL(19),
-	SC27XX_ADC_CHANNEL(20),
-	SC27XX_ADC_CHANNEL(21),
-	SC27XX_ADC_CHANNEL(22),
-	SC27XX_ADC_CHANNEL(23),
-	SC27XX_ADC_CHANNEL(24),
-	SC27XX_ADC_CHANNEL(25),
-	SC27XX_ADC_CHANNEL(26),
-	SC27XX_ADC_CHANNEL(27),
-	SC27XX_ADC_CHANNEL(28),
-	SC27XX_ADC_CHANNEL(29),
-	SC27XX_ADC_CHANNEL(30),
-	SC27XX_ADC_CHANNEL(31),
+	SC27XX_ADC_CHANNEL(0, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(1, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(2, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(3, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(4, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(5, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(6, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(7, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(8, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(9, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(10, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(11, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(12, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(13, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(14, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(15, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(16, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(17, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(18, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(19, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(20, BIT(IIO_CHAN_INFO_RAW)),
+	SC27XX_ADC_CHANNEL(21, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(22, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(23, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(24, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(25, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(26, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(27, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(28, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(29, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(30, BIT(IIO_CHAN_INFO_PROCESSED)),
+	SC27XX_ADC_CHANNEL(31, BIT(IIO_CHAN_INFO_PROCESSED)),
 };
 
 static int sc27xx_adc_enable(struct sc27xx_adc_data *data)