* [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-08-27 12:19 ` Vignesh R
0 siblings, 0 replies; 19+ messages in thread
From: Vignesh R @ 2014-08-27 12:19 UTC (permalink / raw)
To: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron
Cc: Randy Dunlap, Samuel Ortiz, Lee Jones, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Vignesh R
Number of averaging, open delay, sample delay are made DT parameters.
By decreasing averaging and delays more samples can be obtained per
second increasing performance of ADC. Previously the number of
averages per step was fixed to 16. Making these parameters
configurable will help in balancing speed vs accuracy.
For each ADC step provide DT based paramters to set open delay,
sample delay and number of averaging. One configurable step is
used per ADC channel. Since there can be atmost 8 ADC channels,
steps 16 to 8 are used for ADC.
Signed-off-by: Vignesh R <vigneshr@ti.com>
---
.../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
include/linux/mfd/ti_am335x_tscadc.h | 3 ++
3 files changed, 63 insertions(+), 7 deletions(-)
diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
index 878549b..09ac097 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
@@ -27,6 +27,21 @@ Required properties:
- child "adc"
ti,adc-channels: List of analog inputs available for ADC.
AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
+Optional properties:
+- child "adc"
+ ti,step-opendelay: List of open delays for each channel of ADC in the order
+ of ti,adc-channels. This value is written to corresponding
+ step-config register. Default value is 0x098.
+ Maximum value is 0x3FFF.
+ ti,step-sampledelay: List of sample delays for each channel of ADC in the order
+ of ti,adc-channels. This value is written to corresponding
+ step-config register. Default value is 0x0.
+ Maximum value is 0xFF.
+ ti,step-average: Number of averages to be performed for each channel of ADC.
+ If average is 16 then input is sampled 16 times and averaged to
+ get more accurate value. This increases the time taken by ADC
+ to generate a sample. Valid range is 0 average to 16 averages.
+ Default value is 16. Maximum value is 16.
Example:
tscadc: tscadc@44e0d000 {
@@ -40,5 +55,8 @@ Example:
adc {
ti,adc-channels = <4 5 6 7>;
+ ti,step-opendelay = <0x098 0x3FFFF 0x098 0x0>;
+ ti,step-sampledelay = <0xFF 0x0 0xF 0x0>;
+ ti,step-average = <16 2 4 8>;
};
}
diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index dfb0db0..2b31ef2 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -37,6 +37,7 @@ struct tiadc_device {
u8 channel_line[8];
u8 channel_step[8];
int buffer_en_ch_steps;
+ u32 open_delay[8], sample_delay[8], step_avg[8];
u16 data[8];
};
@@ -86,6 +87,7 @@ static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
static void tiadc_step_config(struct iio_dev *indio_dev)
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
+ struct device *dev = adc_dev->mfd_tscadc->dev;
unsigned int stepconfig;
int i, steps;
@@ -100,20 +102,41 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
*/
steps = TOTAL_STEPS - adc_dev->channels;
- if (iio_buffer_enabled(indio_dev))
- stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
- | STEPCONFIG_MODE_SWCNT;
- else
- stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
-
for (i = 0; i < adc_dev->channels; i++) {
int chan;
chan = adc_dev->channel_line[i];
+
+ if (adc_dev->step_avg[i] > STEPCONFIG_AVG_MAX) {
+ dev_warn(dev, "channel %d step average exceeds max value, truncating to %d\n",
+ chan, STEPCONFIG_AVG_MAX);
+ adc_dev->step_avg[i] = STEPCONFIG_AVG_MAX;
+ }
+
+ stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
+ STEPCONFIG_FIFO1;
+
+ if (iio_buffer_enabled(indio_dev))
+ stepconfig |= STEPCONFIG_MODE_SWCNT;
+
tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
stepconfig | STEPCONFIG_INP(chan));
+
+ if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MAX) {
+ dev_warn(dev, "channel %d step delay open exceeds max value, truncating to %d\n",
+ chan, STEPDELAY_OPEN_MAX);
+ adc_dev->open_delay[i] = STEPDELAY_OPEN_MAX;
+ }
+
+ if (adc_dev->sample_delay[i] > STEPDELAY_SAMPLE_MAX) {
+ dev_warn(dev, "channel %d step delay sample max value, truncating to %d\n",
+ chan, STEPDELAY_SAMPLE_MAX);
+ adc_dev->sample_delay[i] = STEPDELAY_SAMPLE_MAX;
+ }
+
tiadc_writel(adc_dev, REG_STEPDELAY(steps),
- STEPCONFIG_OPENDLY);
+ STEPDELAY_OPEN(adc_dev->open_delay[i]) |
+ STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
adc_dev->channel_step[i] = steps;
steps++;
}
@@ -418,10 +441,22 @@ static int tiadc_parse_dt(struct platform_device *pdev,
of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
adc_dev->channel_line[channels] = val;
+
+ /* Set Default values for optional DT parameters */
+ adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
+ adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
+ adc_dev->step_avg[channels] = 16;
channels++;
}
adc_dev->channels = channels;
+ of_property_read_u32_array(node, "ti,step-average",
+ adc_dev->step_avg, channels);
+ of_property_read_u32_array(node, "ti,step-opendelay",
+ adc_dev->open_delay, channels);
+ of_property_read_u32_array(node, "ti,step-sampledelay",
+ adc_dev->sample_delay, channels);
+
return 0;
}
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index fb96c84..26d3e84 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -82,14 +82,17 @@
#define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
#define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
#define STEPCONFIG_FIFO1 BIT(26)
+#define STEPCONFIG_AVG_MAX 16
/* Delay register */
#define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
#define STEPDELAY_OPEN(val) ((val) << 0)
#define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
+#define STEPDELAY_OPEN_MAX 0x3FFFF
#define STEPDELAY_SAMPLE_MASK (0xFF << 24)
#define STEPDELAY_SAMPLE(val) ((val) << 24)
#define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
+#define STEPDELAY_SAMPLE_MAX 0xFF
/* Charge Config */
#define STEPCHARGE_RFP_MASK (7 << 12)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-08-27 13:56 ` Lee Jones
0 siblings, 0 replies; 19+ messages in thread
From: Lee Jones @ 2014-08-27 13:56 UTC (permalink / raw)
To: Vignesh R
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron, Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio
On Wed, 27 Aug 2014, Vignesh R wrote:
> Number of averaging, open delay, sample delay are made DT parameters.
> By decreasing averaging and delays more samples can be obtained per
> second increasing performance of ADC. Previously the number of
> averages per step was fixed to 16. Making these parameters
> configurable will help in balancing speed vs accuracy.
> For each ADC step provide DT based paramters to set open delay,
> sample delay and number of averaging. One configurable step is
> used per ADC channel. Since there can be atmost 8 ADC channels,
> steps 16 to 8 are used for ADC.
>
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
> 3 files changed, 63 insertions(+), 7 deletions(-)
[...]
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index fb96c84..26d3e84 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -82,14 +82,17 @@
There are so many different formats at play here, it's difficult to
see what's happening where!
> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
> #define STEPCONFIG_FIFO1 BIT(26)
> +#define STEPCONFIG_AVG_MAX 16
>
> /* Delay register */
> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
> #define STEPDELAY_OPEN(val) ((val) << 0)
What's the point in shifting by zero?
> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
> +#define STEPDELAY_OPEN_MAX 0x3FFFF
Put this up the top, then you can use it when defining
STEPDELAY_OPEN_MASK.
> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
> #define STEPDELAY_SAMPLE(val) ((val) << 24)
> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
> +#define STEPDELAY_SAMPLE_MAX 0xFF
> /* Charge Config */
> #define STEPCHARGE_RFP_MASK (7 << 12)
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-08-27 13:56 ` Lee Jones
0 siblings, 0 replies; 19+ messages in thread
From: Lee Jones @ 2014-08-27 13:56 UTC (permalink / raw)
To: Vignesh R
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron, Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree-u79uwXL29TY76Z2rM5mHXA,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-iio-u79uwXL29TY76Z2rM5mHXA
On Wed, 27 Aug 2014, Vignesh R wrote:
> Number of averaging, open delay, sample delay are made DT parameters.
> By decreasing averaging and delays more samples can be obtained per
> second increasing performance of ADC. Previously the number of
> averages per step was fixed to 16. Making these parameters
> configurable will help in balancing speed vs accuracy.
> For each ADC step provide DT based paramters to set open delay,
> sample delay and number of averaging. One configurable step is
> used per ADC channel. Since there can be atmost 8 ADC channels,
> steps 16 to 8 are used for ADC.
>
> Signed-off-by: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
> ---
> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
> 3 files changed, 63 insertions(+), 7 deletions(-)
[...]
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index fb96c84..26d3e84 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -82,14 +82,17 @@
There are so many different formats at play here, it's difficult to
see what's happening where!
> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
> #define STEPCONFIG_FIFO1 BIT(26)
> +#define STEPCONFIG_AVG_MAX 16
>
> /* Delay register */
> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
> #define STEPDELAY_OPEN(val) ((val) << 0)
What's the point in shifting by zero?
> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
> +#define STEPDELAY_OPEN_MAX 0x3FFFF
Put this up the top, then you can use it when defining
STEPDELAY_OPEN_MASK.
> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
> #define STEPDELAY_SAMPLE(val) ((val) << 24)
> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
> +#define STEPDELAY_SAMPLE_MAX 0xFF
> /* Charge Config */
> #define STEPCHARGE_RFP_MASK (7 << 12)
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
2014-08-27 13:56 ` Lee Jones
@ 2014-08-28 5:12 ` Vignesh R
-1 siblings, 0 replies; 19+ messages in thread
From: Vignesh R @ 2014-08-28 5:12 UTC (permalink / raw)
To: Lee Jones
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron, Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
Hi,
On Wednesday 27 August 2014 07:26 PM, Lee Jones wrote:
> On Wed, 27 Aug 2014, Vignesh R wrote:
>
>> Number of averaging, open delay, sample delay are made DT parameters.
>> By decreasing averaging and delays more samples can be obtained per
>> second increasing performance of ADC. Previously the number of
>> averages per step was fixed to 16. Making these parameters
>> configurable will help in balancing speed vs accuracy.
>> For each ADC step provide DT based paramters to set open delay,
>> sample delay and number of averaging. One configurable step is
>> used per ADC channel. Since there can be atmost 8 ADC channels,
>> steps 16 to 8 are used for ADC.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>> 3 files changed, 63 insertions(+), 7 deletions(-)
>
> [...]
>
>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>> index fb96c84..26d3e84 100644
>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>> @@ -82,14 +82,17 @@
>
> There are so many different formats at play here, it's difficult to
> see what's happening where!
I did not understand "different formats". Please explain.
>
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>> +#define STEPCONFIG_AVG_MAX 16
>>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>
> What's the point in shifting by zero?
I agree. But my patch did not add these lines. I can remove them. Do you
want me to do this change as part of current patch or as a separate
cleanup patch?
>
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>> +#define STEPDELAY_OPEN_MAX 0x3FFFF
>
> Put this up the top, then you can use it when defining
> STEPDELAY_OPEN_MASK.
Done.
>
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>> +#define STEPDELAY_SAMPLE_MAX 0xFF
>
>> /* Charge Config */
>> #define STEPCHARGE_RFP_MASK (7 << 12)
>
Regards
Vignesh R
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-08-28 5:12 ` Vignesh R
0 siblings, 0 replies; 19+ messages in thread
From: Vignesh R @ 2014-08-28 5:12 UTC (permalink / raw)
To: Lee Jones
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron, Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
Hi,
On Wednesday 27 August 2014 07:26 PM, Lee Jones wrote:
> On Wed, 27 Aug 2014, Vignesh R wrote:
>
>> Number of averaging, open delay, sample delay are made DT parameters.
>> By decreasing averaging and delays more samples can be obtained per
>> second increasing performance of ADC. Previously the number of
>> averages per step was fixed to 16. Making these parameters
>> configurable will help in balancing speed vs accuracy.
>> For each ADC step provide DT based paramters to set open delay,
>> sample delay and number of averaging. One configurable step is
>> used per ADC channel. Since there can be atmost 8 ADC channels,
>> steps 16 to 8 are used for ADC.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>> 3 files changed, 63 insertions(+), 7 deletions(-)
>
> [...]
>
>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>> index fb96c84..26d3e84 100644
>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>> @@ -82,14 +82,17 @@
>
> There are so many different formats at play here, it's difficult to
> see what's happening where!
I did not understand "different formats". Please explain.
>
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>> +#define STEPCONFIG_AVG_MAX 16
>>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>
> What's the point in shifting by zero?
I agree. But my patch did not add these lines. I can remove them. Do you
want me to do this change as part of current patch or as a separate
cleanup patch?
>
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>> +#define STEPDELAY_OPEN_MAX 0x3FFFF
>
> Put this up the top, then you can use it when defining
> STEPDELAY_OPEN_MASK.
Done.
>
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>> +#define STEPDELAY_SAMPLE_MAX 0xFF
>
>> /* Charge Config */
>> #define STEPCHARGE_RFP_MASK (7 << 12)
>
Regards
Vignesh R
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
2014-08-28 5:12 ` Vignesh R
(?)
@ 2014-08-28 7:11 ` Lee Jones
2014-08-30 9:34 ` Jonathan Cameron
-1 siblings, 1 reply; 19+ messages in thread
From: Lee Jones @ 2014-08-28 7:11 UTC (permalink / raw)
To: Vignesh R
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Jonathan Cameron, Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
On Thu, 28 Aug 2014, Vignesh R wrote:
> On Wednesday 27 August 2014 07:26 PM, Lee Jones wrote:
> > On Wed, 27 Aug 2014, Vignesh R wrote:
> >
> >> Number of averaging, open delay, sample delay are made DT parameters.
> >> By decreasing averaging and delays more samples can be obtained per
> >> second increasing performance of ADC. Previously the number of
> >> averages per step was fixed to 16. Making these parameters
> >> configurable will help in balancing speed vs accuracy.
> >> For each ADC step provide DT based paramters to set open delay,
> >> sample delay and number of averaging. One configurable step is
> >> used per ADC channel. Since there can be atmost 8 ADC channels,
> >> steps 16 to 8 are used for ADC.
> >>
> >> Signed-off-by: Vignesh R <vigneshr@ti.com>
> >> ---
> >> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
> >> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
> >> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
> >> 3 files changed, 63 insertions(+), 7 deletions(-)
> >
> > [...]
> >
> >> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> >> index fb96c84..26d3e84 100644
> >> --- a/include/linux/mfd/ti_am335x_tscadc.h
> >> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> >> @@ -82,14 +82,17 @@
> >
> > There are so many different formats at play here, it's difficult to
> > see what's happening where!
>
> I did not understand "different formats". Please explain.
My complaint is with the existing layout, rather than your patch:
> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
> #define STEPCONFIG_FIFO1 BIT(26)
Base10 MACROS.
#define STEPCONFIG_AVG_MAX 16
Base10 int.
> /* Delay register */
> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
Base16 shift.
> #define STEPDELAY_OPEN(val) ((val) << 0)
MACRO shift.
> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
Base16 MACRO.
> #define STEPDELAY_OPEN_MAX 0x3FFFF
Base16 int.
> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
Base16 shift.
> #define STEPDELAY_SAMPLE(val) ((val) << 24)
MACRO shift.
> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
24 shift of 0 (still zero?).
> #define STEPDELAY_SAMPLE_MAX 0xFF
Base16 int.
There is no consistency here, it's just a bunch of 'stuff', which
makes making sense of them all difficult.
> >> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
> >> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
> >> #define STEPCONFIG_FIFO1 BIT(26)
> >> +#define STEPCONFIG_AVG_MAX 16
> >>
> >> /* Delay register */
> >> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
> >> #define STEPDELAY_OPEN(val) ((val) << 0)
> >
> > What's the point in shifting by zero?
>
> I agree. But my patch did not add these lines. I can remove them. Do you
> want me to do this change as part of current patch or as a separate
> cleanup patch?
That's up to Jonathan.
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
2014-08-28 7:11 ` Lee Jones
@ 2014-08-30 9:34 ` Jonathan Cameron
0 siblings, 0 replies; 19+ messages in thread
From: Jonathan Cameron @ 2014-08-30 9:34 UTC (permalink / raw)
To: Lee Jones, Vignesh R
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
On 28/08/14 08:11, Lee Jones wrote:
> On Thu, 28 Aug 2014, Vignesh R wrote:
>> On Wednesday 27 August 2014 07:26 PM, Lee Jones wrote:
>>> On Wed, 27 Aug 2014, Vignesh R wrote:
>>>
>>>> Number of averaging, open delay, sample delay are made DT parameters.
>>>> By decreasing averaging and delays more samples can be obtained per
>>>> second increasing performance of ADC. Previously the number of
>>>> averages per step was fixed to 16. Making these parameters
>>>> configurable will help in balancing speed vs accuracy.
>>>> For each ADC step provide DT based paramters to set open delay,
>>>> sample delay and number of averaging. One configurable step is
>>>> used per ADC channel. Since there can be atmost 8 ADC channels,
>>>> steps 16 to 8 are used for ADC.
>>>>
>>>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>>>> ---
>>>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>>>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>>>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>>>> 3 files changed, 63 insertions(+), 7 deletions(-)
>>>
>>> [...]
>>>
>>>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>>>> index fb96c84..26d3e84 100644
>>>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>>>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>>>> @@ -82,14 +82,17 @@
>>>
>>> There are so many different formats at play here, it's difficult to
>>> see what's happening where!
>>
>> I did not understand "different formats". Please explain.
>
> My complaint is with the existing layout, rather than your patch:
>
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>
> Base10 MACROS.
>
> #define STEPCONFIG_AVG_MAX 16
>
> Base10 int.
>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>
> Base16 shift.
>
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>
> MACRO shift.
>
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>
> Base16 MACRO.
>
>> #define STEPDELAY_OPEN_MAX 0x3FFFF
>
> Base16 int.
>
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>
> Base16 shift.
>
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>
> MACRO shift.
>
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>
> 24 shift of 0 (still zero?).
>
>> #define STEPDELAY_SAMPLE_MAX 0xFF
>
> Base16 int.
>
> There is no consistency here, it's just a bunch of 'stuff', which
> makes making sense of them all difficult.
>
>>>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>>>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>>>> #define STEPCONFIG_FIFO1 BIT(26)
>>>> +#define STEPCONFIG_AVG_MAX 16
>>>>
>>>> /* Delay register */
>>>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>>>> #define STEPDELAY_OPEN(val) ((val) << 0)
>>>
>>> What's the point in shifting by zero?
>>
>> I agree. But my patch did not add these lines. I can remove them. Do you
>> want me to do this change as part of current patch or as a separate
>> cleanup patch?
>
> That's up to Jonathan.
I'm always happy to take sane cleanups like this. Separate cleanup patch please.
That way it's easy to verify that there are no functional changes without it
getting in the way of the 'interesting' patch.
Thanks,
Jonathan
>
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-08-30 9:34 ` Jonathan Cameron
0 siblings, 0 replies; 19+ messages in thread
From: Jonathan Cameron @ 2014-08-30 9:34 UTC (permalink / raw)
To: Lee Jones, Vignesh R
Cc: Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell, Kumar Gala,
Randy Dunlap, Samuel Ortiz, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree-u79uwXL29TY76Z2rM5mHXA,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-iio-u79uwXL29TY76Z2rM5mHXA, Sekhar Nori
On 28/08/14 08:11, Lee Jones wrote:
> On Thu, 28 Aug 2014, Vignesh R wrote:
>> On Wednesday 27 August 2014 07:26 PM, Lee Jones wrote:
>>> On Wed, 27 Aug 2014, Vignesh R wrote:
>>>
>>>> Number of averaging, open delay, sample delay are made DT parameters.
>>>> By decreasing averaging and delays more samples can be obtained per
>>>> second increasing performance of ADC. Previously the number of
>>>> averages per step was fixed to 16. Making these parameters
>>>> configurable will help in balancing speed vs accuracy.
>>>> For each ADC step provide DT based paramters to set open delay,
>>>> sample delay and number of averaging. One configurable step is
>>>> used per ADC channel. Since there can be atmost 8 ADC channels,
>>>> steps 16 to 8 are used for ADC.
>>>>
>>>> Signed-off-by: Vignesh R <vigneshr-l0cyMroinI0@public.gmane.org>
>>>> ---
>>>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>>>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>>>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>>>> 3 files changed, 63 insertions(+), 7 deletions(-)
>>>
>>> [...]
>>>
>>>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>>>> index fb96c84..26d3e84 100644
>>>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>>>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>>>> @@ -82,14 +82,17 @@
>>>
>>> There are so many different formats at play here, it's difficult to
>>> see what's happening where!
>>
>> I did not understand "different formats". Please explain.
>
> My complaint is with the existing layout, rather than your patch:
>
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>
> Base10 MACROS.
>
> #define STEPCONFIG_AVG_MAX 16
>
> Base10 int.
>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>
> Base16 shift.
>
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>
> MACRO shift.
>
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>
> Base16 MACRO.
>
>> #define STEPDELAY_OPEN_MAX 0x3FFFF
>
> Base16 int.
>
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>
> Base16 shift.
>
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>
> MACRO shift.
>
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>
> 24 shift of 0 (still zero?).
>
>> #define STEPDELAY_SAMPLE_MAX 0xFF
>
> Base16 int.
>
> There is no consistency here, it's just a bunch of 'stuff', which
> makes making sense of them all difficult.
>
>>>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>>>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>>>> #define STEPCONFIG_FIFO1 BIT(26)
>>>> +#define STEPCONFIG_AVG_MAX 16
>>>>
>>>> /* Delay register */
>>>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>>>> #define STEPDELAY_OPEN(val) ((val) << 0)
>>>
>>> What's the point in shifting by zero?
>>
>> I agree. But my patch did not add these lines. I can remove them. Do you
>> want me to do this change as part of current patch or as a separate
>> cleanup patch?
>
> That's up to Jonathan.
I'm always happy to take sane cleanups like this. Separate cleanup patch please.
That way it's easy to verify that there are no functional changes without it
getting in the way of the 'interesting' patch.
Thanks,
Jonathan
>
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
2014-08-27 12:19 ` Vignesh R
(?)
(?)
@ 2014-08-30 9:43 ` Jonathan Cameron
2014-09-01 6:40 ` Vignesh R
-1 siblings, 1 reply; 19+ messages in thread
From: Jonathan Cameron @ 2014-08-30 9:43 UTC (permalink / raw)
To: Vignesh R, Rob Herring, Pawel Moll, Mark Rutland, Ian Campbell,
Kumar Gala
Cc: Randy Dunlap, Samuel Ortiz, Lee Jones, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio
On 27/08/14 13:19, Vignesh R wrote:
> Number of averaging, open delay, sample delay are made DT parameters.
> By decreasing averaging and delays more samples can be obtained per
> second increasing performance of ADC. Previously the number of
> averages per step was fixed to 16. Making these parameters
> configurable will help in balancing speed vs accuracy.
> For each ADC step provide DT based paramters to set open delay,
> sample delay and number of averaging. One configurable step is
> used per ADC channel. Since there can be atmost 8 ADC channels,
> steps 16 to 8 are used for ADC.
>
> Signed-off-by: Vignesh R <vigneshr@ti.com>
My main question here is whether these make sense purely as DT parameters
or whether userspace control would be useful? Still, even if we add that
later, there is nothing wrong with specifying an initial value in the DT.
Average in particular strikes me as a straight forward parameter where userspace
control might make sense...
Mostly fine, but I think your example has a stray F.
J
> ---
> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
> 3 files changed, 63 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> index 878549b..09ac097 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> @@ -27,6 +27,21 @@ Required properties:
> - child "adc"
> ti,adc-channels: List of analog inputs available for ADC.
> AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
> +Optional properties:
> +- child "adc"
> + ti,step-opendelay: List of open delays for each channel of ADC in the order
> + of ti,adc-channels. This value is written to corresponding
> + step-config register. Default value is 0x098.
> + Maximum value is 0x3FFF.
Any chance of real numbers in here rather than magic constants? If they are real
numbers, then some explanation of how they relate to time would be good. I also wonder if we
need to name them after steps here, given they correspond directly to adc channels.
> + ti,step-sampledelay: List of sample delays for each channel of ADC in the order
> + of ti,adc-channels. This value is written to corresponding
> + step-config register. Default value is 0x0.
> + Maximum value is 0xFF.
> + ti,step-average: Number of averages to be performed for each channel of ADC.
> + If average is 16 then input is sampled 16 times and averaged to
> + get more accurate value. This increases the time taken by ADC
> + to generate a sample. Valid range is 0 average to 16 averages.
> + Default value is 16. Maximum value is 16.
>
> Example:
> tscadc: tscadc@44e0d000 {
> @@ -40,5 +55,8 @@ Example:
>
> adc {
> ti,adc-channels = <4 5 6 7>;
> + ti,step-opendelay = <0x098 0x3FFFF 0x098 0x0>;
too many F's?
> + ti,step-sampledelay = <0xFF 0x0 0xF 0x0>;
> + ti,step-average = <16 2 4 8>;
> };
> }
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index dfb0db0..2b31ef2 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -37,6 +37,7 @@ struct tiadc_device {
> u8 channel_line[8];
> u8 channel_step[8];
> int buffer_en_ch_steps;
> + u32 open_delay[8], sample_delay[8], step_avg[8];
> u16 data[8];
> };
>
> @@ -86,6 +87,7 @@ static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
> static void tiadc_step_config(struct iio_dev *indio_dev)
> {
> struct tiadc_device *adc_dev = iio_priv(indio_dev);
> + struct device *dev = adc_dev->mfd_tscadc->dev;
> unsigned int stepconfig;
> int i, steps;
>
> @@ -100,20 +102,41 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
> */
>
> steps = TOTAL_STEPS - adc_dev->channels;
> - if (iio_buffer_enabled(indio_dev))
> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
> - | STEPCONFIG_MODE_SWCNT;
> - else
> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
> -
> for (i = 0; i < adc_dev->channels; i++) {
> int chan;
>
> chan = adc_dev->channel_line[i];
> +
> + if (adc_dev->step_avg[i] > STEPCONFIG_AVG_MAX) {
> + dev_warn(dev, "channel %d step average exceeds max value, truncating to %d\n",
> + chan, STEPCONFIG_AVG_MAX);
> + adc_dev->step_avg[i] = STEPCONFIG_AVG_MAX;
> + }
> +
> + stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
> + STEPCONFIG_FIFO1;
> +
> + if (iio_buffer_enabled(indio_dev))
> + stepconfig |= STEPCONFIG_MODE_SWCNT;
> +
> tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
> stepconfig | STEPCONFIG_INP(chan));
> +
> + if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MAX) {
> + dev_warn(dev, "channel %d step delay open exceeds max value, truncating to %d\n",
> + chan, STEPDELAY_OPEN_MAX);
> + adc_dev->open_delay[i] = STEPDELAY_OPEN_MAX;
> + }
> +
> + if (adc_dev->sample_delay[i] > STEPDELAY_SAMPLE_MAX) {
> + dev_warn(dev, "channel %d step delay sample max value, truncating to %d\n",
> + chan, STEPDELAY_SAMPLE_MAX);
> + adc_dev->sample_delay[i] = STEPDELAY_SAMPLE_MAX;
> + }
> +
> tiadc_writel(adc_dev, REG_STEPDELAY(steps),
> - STEPCONFIG_OPENDLY);
> + STEPDELAY_OPEN(adc_dev->open_delay[i]) |
> + STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
> adc_dev->channel_step[i] = steps;
> steps++;
> }
> @@ -418,10 +441,22 @@ static int tiadc_parse_dt(struct platform_device *pdev,
>
> of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
> adc_dev->channel_line[channels] = val;
> +
> + /* Set Default values for optional DT parameters */
> + adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
> + adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
> + adc_dev->step_avg[channels] = 16;
> channels++;
> }
>
> adc_dev->channels = channels;
> + of_property_read_u32_array(node, "ti,step-average",
> + adc_dev->step_avg, channels);
> + of_property_read_u32_array(node, "ti,step-opendelay",
> + adc_dev->open_delay, channels);
> + of_property_read_u32_array(node, "ti,step-sampledelay",
> + adc_dev->sample_delay, channels);
> +
> return 0;
> }
>
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index fb96c84..26d3e84 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -82,14 +82,17 @@
> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
> #define STEPCONFIG_FIFO1 BIT(26)
> +#define STEPCONFIG_AVG_MAX 16
>
> /* Delay register */
> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
> #define STEPDELAY_OPEN(val) ((val) << 0)
> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
> +#define STEPDELAY_OPEN_MAX 0x3FFFF
> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
> #define STEPDELAY_SAMPLE(val) ((val) << 24)
> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
> +#define STEPDELAY_SAMPLE_MAX 0xFF
>
> /* Charge Config */
> #define STEPCHARGE_RFP_MASK (7 << 12)
>
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
2014-08-30 9:43 ` Jonathan Cameron
@ 2014-09-01 6:40 ` Vignesh R
0 siblings, 0 replies; 19+ messages in thread
From: Vignesh R @ 2014-09-01 6:40 UTC (permalink / raw)
To: Jonathan Cameron, Rob Herring, Pawel Moll, Mark Rutland,
Ian Campbell, Kumar Gala
Cc: Randy Dunlap, Samuel Ortiz, Lee Jones, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
Hi,
On Saturday 30 August 2014 03:13 PM, Jonathan Cameron wrote:
> On 27/08/14 13:19, Vignesh R wrote:
>> Number of averaging, open delay, sample delay are made DT parameters.
>> By decreasing averaging and delays more samples can be obtained per
>> second increasing performance of ADC. Previously the number of
>> averages per step was fixed to 16. Making these parameters
>> configurable will help in balancing speed vs accuracy.
>> For each ADC step provide DT based paramters to set open delay,
>> sample delay and number of averaging. One configurable step is
>> used per ADC channel. Since there can be atmost 8 ADC channels,
>> steps 16 to 8 are used for ADC.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>
> My main question here is whether these make sense purely as DT parameters
> or whether userspace control would be useful? Still, even if we add that
> later, there is nothing wrong with specifying an initial value in the DT.
>
I agree. These value can act as initial hardware parameters. Will look
at adding userspace control in another patch.
> Average in particular strikes me as a straight forward parameter where userspace
> control might make sense...
>
I looked at Documentation/ABI/testing/sysfs-bus-iio but could not find
any framework support to make step-average a sysfs entry. Looks like I
need to create a new (my hardware specific) sysfs entry?
> Mostly fine, but I think your example has a stray F.
Actually maximum value for step-opendelay is 0x3FFFF (18 bits). I will
correct the documentation.
>
> J
>> ---
>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>> 3 files changed, 63 insertions(+), 7 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> index 878549b..09ac097 100644
>> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> @@ -27,6 +27,21 @@ Required properties:
>> - child "adc"
>> ti,adc-channels: List of analog inputs available for ADC.
>> AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
>> +Optional properties:
>> +- child "adc"
>> + ti,step-opendelay: List of open delays for each channel of ADC in the order
>> + of ti,adc-channels. This value is written to corresponding
>> + step-config register. Default value is 0x098.
>> + Maximum value is 0x3FFF.
>
> Any chance of real numbers in here rather than magic constants? If they are real
> numbers, then some explanation of how they relate to time would be good.
The values correspond to number of ADC clock cycles. I will document the
same. I will also drop the mention of "default value" - thats really a
driver implementation detail and not a DT careabout.
>I also wonder if we need to name them after steps here, given they correspond directly to adc channels.
These values are written to corresponding STEPDELAYX and STEPCONFIGX
registers. The technical reference manual for am335x also says "number
of averages per step". In order to maintain consistency with above
naming conventions I have named these parameters after steps.
I can make it ti,chan-step-average if that feels more right.
>
>> + ti,step-sampledelay: List of sample delays for each channel of ADC in the order
>> + of ti,adc-channels. This value is written to corresponding
>> + step-config register. Default value is 0x0.
>> + Maximum value is 0xFF.
>> + ti,step-average: Number of averages to be performed for each channel of ADC.
>> + If average is 16 then input is sampled 16 times and averaged to
>> + get more accurate value. This increases the time taken by ADC
>> + to generate a sample. Valid range is 0 average to 16 averages.
>> + Default value is 16. Maximum value is 16.
>>
>> Example:
>> tscadc: tscadc@44e0d000 {
>> @@ -40,5 +55,8 @@ Example:
>>
>> adc {
>> ti,adc-channels = <4 5 6 7>;
>> + ti,step-opendelay = <0x098 0x3FFFF 0x098 0x0>;
> too many F's?
>
>> + ti,step-sampledelay = <0xFF 0x0 0xF 0x0>;
>> + ti,step-average = <16 2 4 8>;
>> };
>> }
>> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
>> index dfb0db0..2b31ef2 100644
>> --- a/drivers/iio/adc/ti_am335x_adc.c
>> +++ b/drivers/iio/adc/ti_am335x_adc.c
>> @@ -37,6 +37,7 @@ struct tiadc_device {
>> u8 channel_line[8];
>> u8 channel_step[8];
>> int buffer_en_ch_steps;
>> + u32 open_delay[8], sample_delay[8], step_avg[8];
>> u16 data[8];
>> };
>>
>> @@ -86,6 +87,7 @@ static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
>> static void tiadc_step_config(struct iio_dev *indio_dev)
>> {
>> struct tiadc_device *adc_dev = iio_priv(indio_dev);
>> + struct device *dev = adc_dev->mfd_tscadc->dev;
>> unsigned int stepconfig;
>> int i, steps;
>>
>> @@ -100,20 +102,41 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
>> */
>>
>> steps = TOTAL_STEPS - adc_dev->channels;
>> - if (iio_buffer_enabled(indio_dev))
>> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
>> - | STEPCONFIG_MODE_SWCNT;
>> - else
>> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
>> -
>> for (i = 0; i < adc_dev->channels; i++) {
>> int chan;
>>
>> chan = adc_dev->channel_line[i];
>> +
>> + if (adc_dev->step_avg[i] > STEPCONFIG_AVG_MAX) {
>> + dev_warn(dev, "channel %d step average exceeds max value, truncating to %d\n",
>> + chan, STEPCONFIG_AVG_MAX);
>> + adc_dev->step_avg[i] = STEPCONFIG_AVG_MAX;
>> + }
>> +
>> + stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
>> + STEPCONFIG_FIFO1;
>> +
>> + if (iio_buffer_enabled(indio_dev))
>> + stepconfig |= STEPCONFIG_MODE_SWCNT;
>> +
>> tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
>> stepconfig | STEPCONFIG_INP(chan));
>> +
>> + if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MAX) {
>> + dev_warn(dev, "channel %d step delay open exceeds max value, truncating to %d\n",
>> + chan, STEPDELAY_OPEN_MAX);
>> + adc_dev->open_delay[i] = STEPDELAY_OPEN_MAX;
>> + }
>> +
>> + if (adc_dev->sample_delay[i] > STEPDELAY_SAMPLE_MAX) {
>> + dev_warn(dev, "channel %d step delay sample max value, truncating to %d\n",
>> + chan, STEPDELAY_SAMPLE_MAX);
>> + adc_dev->sample_delay[i] = STEPDELAY_SAMPLE_MAX;
>> + }
>> +
>> tiadc_writel(adc_dev, REG_STEPDELAY(steps),
>> - STEPCONFIG_OPENDLY);
>> + STEPDELAY_OPEN(adc_dev->open_delay[i]) |
>> + STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
>> adc_dev->channel_step[i] = steps;
>> steps++;
>> }
>> @@ -418,10 +441,22 @@ static int tiadc_parse_dt(struct platform_device *pdev,
>>
>> of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
>> adc_dev->channel_line[channels] = val;
>> +
>> + /* Set Default values for optional DT parameters */
>> + adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
>> + adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
>> + adc_dev->step_avg[channels] = 16;
>> channels++;
>> }
>>
>> adc_dev->channels = channels;
>> + of_property_read_u32_array(node, "ti,step-average",
>> + adc_dev->step_avg, channels);
>> + of_property_read_u32_array(node, "ti,step-opendelay",
>> + adc_dev->open_delay, channels);
>> + of_property_read_u32_array(node, "ti,step-sampledelay",
>> + adc_dev->sample_delay, channels);
>> +
>> return 0;
>> }
>>
>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>> index fb96c84..26d3e84 100644
>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>> @@ -82,14 +82,17 @@
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>> +#define STEPCONFIG_AVG_MAX 16
>>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>> +#define STEPDELAY_OPEN_MAX 0x3FFFF
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>> +#define STEPDELAY_SAMPLE_MAX 0xFF
>>
>> /* Charge Config */
>> #define STEPCHARGE_RFP_MASK (7 << 12)
>>
Regards
Vignesh R
^ permalink raw reply [flat|nested] 19+ messages in thread* Re: [PATCH 2/2] iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
@ 2014-09-01 6:40 ` Vignesh R
0 siblings, 0 replies; 19+ messages in thread
From: Vignesh R @ 2014-09-01 6:40 UTC (permalink / raw)
To: Jonathan Cameron, Rob Herring, Pawel Moll, Mark Rutland,
Ian Campbell, Kumar Gala
Cc: Randy Dunlap, Samuel Ortiz, Lee Jones, Felipe Balbi,
Sebastian Andrzej Siewior, devicetree, linux-doc, linux-iio,
Sekhar Nori
Hi,
On Saturday 30 August 2014 03:13 PM, Jonathan Cameron wrote:
> On 27/08/14 13:19, Vignesh R wrote:
>> Number of averaging, open delay, sample delay are made DT parameters.
>> By decreasing averaging and delays more samples can be obtained per
>> second increasing performance of ADC. Previously the number of
>> averages per step was fixed to 16. Making these parameters
>> configurable will help in balancing speed vs accuracy.
>> For each ADC step provide DT based paramters to set open delay,
>> sample delay and number of averaging. One configurable step is
>> used per ADC channel. Since there can be atmost 8 ADC channels,
>> steps 16 to 8 are used for ADC.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>
> My main question here is whether these make sense purely as DT parameters
> or whether userspace control would be useful? Still, even if we add that
> later, there is nothing wrong with specifying an initial value in the DT.
>
I agree. These value can act as initial hardware parameters. Will look
at adding userspace control in another patch.
> Average in particular strikes me as a straight forward parameter where userspace
> control might make sense...
>
I looked at Documentation/ABI/testing/sysfs-bus-iio but could not find
any framework support to make step-average a sysfs entry. Looks like I
need to create a new (my hardware specific) sysfs entry?
> Mostly fine, but I think your example has a stray F.
Actually maximum value for step-opendelay is 0x3FFFF (18 bits). I will
correct the documentation.
>
> J
>> ---
>> .../bindings/input/touchscreen/ti-tsc-adc.txt | 18 +++++++
>> drivers/iio/adc/ti_am335x_adc.c | 49 +++++++++++++++++---
>> include/linux/mfd/ti_am335x_tscadc.h | 3 ++
>> 3 files changed, 63 insertions(+), 7 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> index 878549b..09ac097 100644
>> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
>> @@ -27,6 +27,21 @@ Required properties:
>> - child "adc"
>> ti,adc-channels: List of analog inputs available for ADC.
>> AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
>> +Optional properties:
>> +- child "adc"
>> + ti,step-opendelay: List of open delays for each channel of ADC in the order
>> + of ti,adc-channels. This value is written to corresponding
>> + step-config register. Default value is 0x098.
>> + Maximum value is 0x3FFF.
>
> Any chance of real numbers in here rather than magic constants? If they are real
> numbers, then some explanation of how they relate to time would be good.
The values correspond to number of ADC clock cycles. I will document the
same. I will also drop the mention of "default value" - thats really a
driver implementation detail and not a DT careabout.
>I also wonder if we need to name them after steps here, given they correspond directly to adc channels.
These values are written to corresponding STEPDELAYX and STEPCONFIGX
registers. The technical reference manual for am335x also says "number
of averages per step". In order to maintain consistency with above
naming conventions I have named these parameters after steps.
I can make it ti,chan-step-average if that feels more right.
>
>> + ti,step-sampledelay: List of sample delays for each channel of ADC in the order
>> + of ti,adc-channels. This value is written to corresponding
>> + step-config register. Default value is 0x0.
>> + Maximum value is 0xFF.
>> + ti,step-average: Number of averages to be performed for each channel of ADC.
>> + If average is 16 then input is sampled 16 times and averaged to
>> + get more accurate value. This increases the time taken by ADC
>> + to generate a sample. Valid range is 0 average to 16 averages.
>> + Default value is 16. Maximum value is 16.
>>
>> Example:
>> tscadc: tscadc@44e0d000 {
>> @@ -40,5 +55,8 @@ Example:
>>
>> adc {
>> ti,adc-channels = <4 5 6 7>;
>> + ti,step-opendelay = <0x098 0x3FFFF 0x098 0x0>;
> too many F's?
>
>> + ti,step-sampledelay = <0xFF 0x0 0xF 0x0>;
>> + ti,step-average = <16 2 4 8>;
>> };
>> }
>> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
>> index dfb0db0..2b31ef2 100644
>> --- a/drivers/iio/adc/ti_am335x_adc.c
>> +++ b/drivers/iio/adc/ti_am335x_adc.c
>> @@ -37,6 +37,7 @@ struct tiadc_device {
>> u8 channel_line[8];
>> u8 channel_step[8];
>> int buffer_en_ch_steps;
>> + u32 open_delay[8], sample_delay[8], step_avg[8];
>> u16 data[8];
>> };
>>
>> @@ -86,6 +87,7 @@ static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
>> static void tiadc_step_config(struct iio_dev *indio_dev)
>> {
>> struct tiadc_device *adc_dev = iio_priv(indio_dev);
>> + struct device *dev = adc_dev->mfd_tscadc->dev;
>> unsigned int stepconfig;
>> int i, steps;
>>
>> @@ -100,20 +102,41 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
>> */
>>
>> steps = TOTAL_STEPS - adc_dev->channels;
>> - if (iio_buffer_enabled(indio_dev))
>> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
>> - | STEPCONFIG_MODE_SWCNT;
>> - else
>> - stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
>> -
>> for (i = 0; i < adc_dev->channels; i++) {
>> int chan;
>>
>> chan = adc_dev->channel_line[i];
>> +
>> + if (adc_dev->step_avg[i] > STEPCONFIG_AVG_MAX) {
>> + dev_warn(dev, "channel %d step average exceeds max value, truncating to %d\n",
>> + chan, STEPCONFIG_AVG_MAX);
>> + adc_dev->step_avg[i] = STEPCONFIG_AVG_MAX;
>> + }
>> +
>> + stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
>> + STEPCONFIG_FIFO1;
>> +
>> + if (iio_buffer_enabled(indio_dev))
>> + stepconfig |= STEPCONFIG_MODE_SWCNT;
>> +
>> tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
>> stepconfig | STEPCONFIG_INP(chan));
>> +
>> + if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MAX) {
>> + dev_warn(dev, "channel %d step delay open exceeds max value, truncating to %d\n",
>> + chan, STEPDELAY_OPEN_MAX);
>> + adc_dev->open_delay[i] = STEPDELAY_OPEN_MAX;
>> + }
>> +
>> + if (adc_dev->sample_delay[i] > STEPDELAY_SAMPLE_MAX) {
>> + dev_warn(dev, "channel %d step delay sample max value, truncating to %d\n",
>> + chan, STEPDELAY_SAMPLE_MAX);
>> + adc_dev->sample_delay[i] = STEPDELAY_SAMPLE_MAX;
>> + }
>> +
>> tiadc_writel(adc_dev, REG_STEPDELAY(steps),
>> - STEPCONFIG_OPENDLY);
>> + STEPDELAY_OPEN(adc_dev->open_delay[i]) |
>> + STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
>> adc_dev->channel_step[i] = steps;
>> steps++;
>> }
>> @@ -418,10 +441,22 @@ static int tiadc_parse_dt(struct platform_device *pdev,
>>
>> of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
>> adc_dev->channel_line[channels] = val;
>> +
>> + /* Set Default values for optional DT parameters */
>> + adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
>> + adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
>> + adc_dev->step_avg[channels] = 16;
>> channels++;
>> }
>>
>> adc_dev->channels = channels;
>> + of_property_read_u32_array(node, "ti,step-average",
>> + adc_dev->step_avg, channels);
>> + of_property_read_u32_array(node, "ti,step-opendelay",
>> + adc_dev->open_delay, channels);
>> + of_property_read_u32_array(node, "ti,step-sampledelay",
>> + adc_dev->sample_delay, channels);
>> +
>> return 0;
>> }
>>
>> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
>> index fb96c84..26d3e84 100644
>> --- a/include/linux/mfd/ti_am335x_tscadc.h
>> +++ b/include/linux/mfd/ti_am335x_tscadc.h
>> @@ -82,14 +82,17 @@
>> #define STEPCONFIG_INP_AN4 STEPCONFIG_INP(4)
>> #define STEPCONFIG_INP_ADCREFM STEPCONFIG_INP(8)
>> #define STEPCONFIG_FIFO1 BIT(26)
>> +#define STEPCONFIG_AVG_MAX 16
>>
>> /* Delay register */
>> #define STEPDELAY_OPEN_MASK (0x3FFFF << 0)
>> #define STEPDELAY_OPEN(val) ((val) << 0)
>> #define STEPCONFIG_OPENDLY STEPDELAY_OPEN(0x098)
>> +#define STEPDELAY_OPEN_MAX 0x3FFFF
>> #define STEPDELAY_SAMPLE_MASK (0xFF << 24)
>> #define STEPDELAY_SAMPLE(val) ((val) << 24)
>> #define STEPCONFIG_SAMPLEDLY STEPDELAY_SAMPLE(0)
>> +#define STEPDELAY_SAMPLE_MAX 0xFF
>>
>> /* Charge Config */
>> #define STEPCHARGE_RFP_MASK (7 << 12)
>>
Regards
Vignesh R
^ permalink raw reply [flat|nested] 19+ messages in thread