[PATCH 0/2] tscadc: Couple of fixes

[PATCH 0/2] tscadc: Couple of fixes

[Vignesh R]

Couple of fixes for tscadc drivers that I found while adding support for
new SoC. Patches are standalone and can go via individual domain trees.

Vignesh R (2):
  mfd: ti_am335x_tscadc: Provide unique name for child mfd cells
  iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

 drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-
 drivers/mfd/ti_am335x_tscadc.c       | 6 ++++--
 include/linux/mfd/ti_am335x_tscadc.h | 4 ++++
 3 files changed, 12 insertions(+), 3 deletions(-)

-- 
2.19.1

[PATCH 1/2] mfd: ti_am335x_tscadc: Provide unique name for child mfd cells

[Vignesh R]

Provide unique names for child mfd cells, this is required in order to
support registering of multiple instances of same ti_am335x_tscadc IP.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 drivers/mfd/ti_am335x_tscadc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index c2d47d78705b..ee08af34f81d 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -248,7 +248,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
 	if (tsc_wires > 0) {
 		tscadc->tsc_cell = tscadc->used_cells;
 		cell = &tscadc->cells[tscadc->used_cells++];
-		cell->name = "TI-am335x-tsc";
+		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
+					    dev_name(&pdev->dev), "tsc");
 		cell->of_compatible = "ti,am3359-tsc";
 		cell->platform_data = &tscadc;
 		cell->pdata_size = sizeof(tscadc);
@@ -258,7 +259,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
 	if (adc_channels > 0) {
 		tscadc->adc_cell = tscadc->used_cells;
 		cell = &tscadc->cells[tscadc->used_cells++];
-		cell->name = "TI-am335x-adc";
+		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
+					    dev_name(&pdev->dev), "adc");
 		cell->of_compatible = "ti,am3359-adc";
 		cell->platform_data = &tscadc;
 		cell->pdata_size = sizeof(tscadc);
-- 
2.19.1

[PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

[Vignesh R]

When performing single ended measurements with TSCADC, its recommended
to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the
corresponding STEP_CONFIGx register.
Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0)
reference voltage for ADC step needs to be set to VREFP and VREFN
respectively in STEP_CONFIGx register.
Without these changes, there may be variation of as much as ~2% in the
ADC's digital output which is bad for precise measurement.

Signed-off-by: Vignesh R <vigneshr@ti.com>
---
 drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-
 include/linux/mfd/ti_am335x_tscadc.h | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index cafb1dcadc48..9d984f2a8ba7 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -142,7 +142,10 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
 			stepconfig |= STEPCONFIG_MODE_SWCNT;
 
 		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
-				stepconfig | STEPCONFIG_INP(chan));
+				stepconfig | STEPCONFIG_INP(chan) |
+				STEPCONFIG_INM_ADCREFM |
+				STEPCONFIG_RFP_VREFP |
+				STEPCONFIG_RFM_VREFN);
 
 		if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
 			dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index b9a53e013bff..483168403ae5 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -78,6 +78,8 @@
 #define STEPCONFIG_YNN		BIT(8)
 #define STEPCONFIG_XNP		BIT(9)
 #define STEPCONFIG_YPN		BIT(10)
+#define STEPCONFIG_RFP(val)	((val) << 12)
+#define STEPCONFIG_RFP_VREFP	(0x3 << 12)
 #define STEPCONFIG_INM_MASK	(0xF << 15)
 #define STEPCONFIG_INM(val)	((val) << 15)
 #define STEPCONFIG_INM_ADCREFM	STEPCONFIG_INM(8)
@@ -86,6 +88,8 @@
 #define STEPCONFIG_INP_AN4	STEPCONFIG_INP(4)
 #define STEPCONFIG_INP_ADCREFM	STEPCONFIG_INP(8)
 #define STEPCONFIG_FIFO1	BIT(26)
+#define STEPCONFIG_RFM(val)	((val) << 23)
+#define STEPCONFIG_RFM_VREFN	(0x3 << 23)
 
 /* Delay register */
 #define STEPDELAY_OPEN_MASK	(0x3FFFF << 0)
-- 
2.19.1

Re: [PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

[Jonathan Cameron]

On Mon, 19 Nov 2018 12:12:36 +0530
Vignesh R <vigneshr@ti.com> wrote:

> When performing single ended measurements with TSCADC, its recommended
> to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the
> corresponding STEP_CONFIGx register.
> Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0)
> reference voltage for ADC step needs to be set to VREFP and VREFN
> respectively in STEP_CONFIGx register.
> Without these changes, there may be variation of as much as ~2% in the
> ADC's digital output which is bad for precise measurement.
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
Given the header changes in mfd and the fact not much is going on with this
driver in IIO at the moment, I'm happy for this to go through the mfd tree.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Thanks,

Jonathan

> ---
>  drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-
>  include/linux/mfd/ti_am335x_tscadc.h | 4 ++++
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index cafb1dcadc48..9d984f2a8ba7 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -142,7 +142,10 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
>  			stepconfig |= STEPCONFIG_MODE_SWCNT;
>  
>  		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
> -				stepconfig | STEPCONFIG_INP(chan));
> +				stepconfig | STEPCONFIG_INP(chan) |
> +				STEPCONFIG_INM_ADCREFM |
> +				STEPCONFIG_RFP_VREFP |
> +				STEPCONFIG_RFM_VREFN);
>  
>  		if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) {
>  			dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n",
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index b9a53e013bff..483168403ae5 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -78,6 +78,8 @@
>  #define STEPCONFIG_YNN		BIT(8)
>  #define STEPCONFIG_XNP		BIT(9)
>  #define STEPCONFIG_YPN		BIT(10)
> +#define STEPCONFIG_RFP(val)	((val) << 12)
> +#define STEPCONFIG_RFP_VREFP	(0x3 << 12)
>  #define STEPCONFIG_INM_MASK	(0xF << 15)
>  #define STEPCONFIG_INM(val)	((val) << 15)
>  #define STEPCONFIG_INM_ADCREFM	STEPCONFIG_INM(8)
> @@ -86,6 +88,8 @@
>  #define STEPCONFIG_INP_AN4	STEPCONFIG_INP(4)
>  #define STEPCONFIG_INP_ADCREFM	STEPCONFIG_INP(8)
>  #define STEPCONFIG_FIFO1	BIT(26)
> +#define STEPCONFIG_RFM(val)	((val) << 23)
> +#define STEPCONFIG_RFM_VREFN	(0x3 << 23)
>  
>  /* Delay register */
>  #define STEPDELAY_OPEN_MASK	(0x3FFFF << 0)

Re: [PATCH 1/2] mfd: ti_am335x_tscadc: Provide unique name for child mfd cells

[Lee Jones]

On Mon, 19 Nov 2018, Vignesh R wrote:

> Provide unique names for child mfd cells, this is required in order to
> support registering of multiple instances of same ti_am335x_tscadc IP.

I don't think it is.  What is the error you are receiving?

> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  drivers/mfd/ti_am335x_tscadc.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> index c2d47d78705b..ee08af34f81d 100644
> --- a/drivers/mfd/ti_am335x_tscadc.c
> +++ b/drivers/mfd/ti_am335x_tscadc.c
> @@ -248,7 +248,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	if (tsc_wires > 0) {
>  		tscadc->tsc_cell = tscadc->used_cells;
>  		cell = &tscadc->cells[tscadc->used_cells++];
> -		cell->name = "TI-am335x-tsc";
> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
> +					    dev_name(&pdev->dev), "tsc");
>  		cell->of_compatible = "ti,am3359-tsc";
>  		cell->platform_data = &tscadc;
>  		cell->pdata_size = sizeof(tscadc);
> @@ -258,7 +259,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>  	if (adc_channels > 0) {
>  		tscadc->adc_cell = tscadc->used_cells;
>  		cell = &tscadc->cells[tscadc->used_cells++];
> -		cell->name = "TI-am335x-adc";
> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
> +					    dev_name(&pdev->dev), "adc");
>  		cell->of_compatible = "ti,am3359-adc";
>  		cell->platform_data = &tscadc;
>  		cell->pdata_size = sizeof(tscadc);

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

[Lee Jones]

On Mon, 19 Nov 2018, Vignesh R wrote:

> When performing single ended measurements with TSCADC, its recommended
> to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the
> corresponding STEP_CONFIGx register.
> Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0)
> reference voltage for ADC step needs to be set to VREFP and VREFN
> respectively in STEP_CONFIGx register.
> Without these changes, there may be variation of as much as ~2% in the
> ADC's digital output which is bad for precise measurement.
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> ---
>  drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-

>  include/linux/mfd/ti_am335x_tscadc.h | 4 ++++

Acked-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 1/2] mfd: ti_am335x_tscadc: Provide unique name for child mfd cells

[Vignesh R]

Hi,

On 28/11/18 2:37 PM, Lee Jones wrote:
> On Mon, 19 Nov 2018, Vignesh R wrote:
> 
>> Provide unique names for child mfd cells, this is required in order to
>> support registering of multiple instances of same ti_am335x_tscadc IP.
> 
> I don't think it is.  What is the error you are receiving?
> 

W/o this patch I get:

[    2.296839] sysfs: cannot create duplicate filename '/bus/platform/devices/TI-am335x-adc'
[    2.305085] CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 4.20.0-rc3-next-20181123-00018-g
7791ce8f123f-dirty #182
[    2.315254] Hardware name: Texas Instruments AM654 Base Board (DT)
[    2.321447] Workqueue: events deferred_probe_work_func
[    2.326585] Call trace:
[    2.329036]  dump_backtrace+0x0/0x1c0
[    2.332699]  show_stack+0x14/0x20
[    2.336017]  dump_stack+0x9c/0xbc
[    2.339333]  sysfs_warn_dup+0x60/0x78
[    2.342995]  sysfs_do_create_link_sd.isra.0+0xdc/0xe8
[    2.348042]  sysfs_create_link+0x20/0x40
[    2.351963]  bus_add_device+0x68/0x130
[    2.355711]  device_add+0x398/0x618
[    2.359199]  platform_device_add+0x120/0x290
[    2.363469]  mfd_add_device+0x23c/0x2e8
[    2.367302]  mfd_add_devices+0xb4/0x158
[    2.371136]  ti_tscadc_probe+0x35c/0x4c8
[    2.375056]  platform_drv_probe+0x50/0xa0
[    2.379062]  really_probe+0x204/0x2a8
[    2.382722]  driver_probe_device+0x58/0x100
[    2.386903]  __device_attach_driver+0x98/0xf0
[    2.391258]  bus_for_each_drv+0x64/0xc8
[    2.395091]  __device_attach+0xd8/0x138
[    2.398923]  device_initial_probe+0x10/0x18
[    2.403103]  bus_probe_device+0x90/0x98
[    2.406938]  deferred_probe_work_func+0x74/0xb0
[    2.411470]  process_one_work+0x1e0/0x330
[    2.415478]  worker_thread+0x238/0x460
[    2.419225]  kthread+0x128/0x130
[    2.422452]  ret_from_fork+0x10/0x1c
[    2.426195] ti_am3359-tscadc: probe of 40210000.tscadc failed with error -1

>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>> ---
>>  drivers/mfd/ti_am335x_tscadc.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
>> index c2d47d78705b..ee08af34f81d 100644
>> --- a/drivers/mfd/ti_am335x_tscadc.c
>> +++ b/drivers/mfd/ti_am335x_tscadc.c
>> @@ -248,7 +248,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>>  	if (tsc_wires > 0) {
>>  		tscadc->tsc_cell = tscadc->used_cells;
>>  		cell = &tscadc->cells[tscadc->used_cells++];
>> -		cell->name = "TI-am335x-tsc";
>> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
>> +					    dev_name(&pdev->dev), "tsc");
>>  		cell->of_compatible = "ti,am3359-tsc";
>>  		cell->platform_data = &tscadc;
>>  		cell->pdata_size = sizeof(tscadc);
>> @@ -258,7 +259,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>>  	if (adc_channels > 0) {
>>  		tscadc->adc_cell = tscadc->used_cells;
>>  		cell = &tscadc->cells[tscadc->used_cells++];
>> -		cell->name = "TI-am335x-adc";
>> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
>> +					    dev_name(&pdev->dev), "adc");
>>  		cell->of_compatible = "ti,am3359-adc";
>>  		cell->platform_data = &tscadc;
>>  		cell->pdata_size = sizeof(tscadc);
> 

-- 
Regards
Vignesh

Re: [PATCH 1/2] mfd: ti_am335x_tscadc: Provide unique name for child mfd cells

[Lee Jones]

On Wed, 28 Nov 2018, Vignesh R wrote:

> Hi,
> 
> On 28/11/18 2:37 PM, Lee Jones wrote:
> > On Mon, 19 Nov 2018, Vignesh R wrote:
> > 
> >> Provide unique names for child mfd cells, this is required in order to
> >> support registering of multiple instances of same ti_am335x_tscadc IP.
> > 
> > I don't think it is.  What is the error you are receiving?
> 
> W/o this patch I get:
> 
> [    2.296839] sysfs: cannot create duplicate filename '/bus/platform/devices/TI-am335x-adc'
> [    2.305085] CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 4.20.0-rc3-next-20181123-00018-g
> 7791ce8f123f-dirty #182
> [    2.315254] Hardware name: Texas Instruments AM654 Base Board (DT)
> [    2.321447] Workqueue: events deferred_probe_work_func
> [    2.326585] Call trace:
> [    2.329036]  dump_backtrace+0x0/0x1c0
> [    2.332699]  show_stack+0x14/0x20
> [    2.336017]  dump_stack+0x9c/0xbc
> [    2.339333]  sysfs_warn_dup+0x60/0x78
> [    2.342995]  sysfs_do_create_link_sd.isra.0+0xdc/0xe8
> [    2.348042]  sysfs_create_link+0x20/0x40
> [    2.351963]  bus_add_device+0x68/0x130
> [    2.355711]  device_add+0x398/0x618
> [    2.359199]  platform_device_add+0x120/0x290
> [    2.363469]  mfd_add_device+0x23c/0x2e8
> [    2.367302]  mfd_add_devices+0xb4/0x158
> [    2.371136]  ti_tscadc_probe+0x35c/0x4c8
> [    2.375056]  platform_drv_probe+0x50/0xa0
> [    2.379062]  really_probe+0x204/0x2a8
> [    2.382722]  driver_probe_device+0x58/0x100
> [    2.386903]  __device_attach_driver+0x98/0xf0
> [    2.391258]  bus_for_each_drv+0x64/0xc8
> [    2.395091]  __device_attach+0xd8/0x138
> [    2.398923]  device_initial_probe+0x10/0x18
> [    2.403103]  bus_probe_device+0x90/0x98
> [    2.406938]  deferred_probe_work_func+0x74/0xb0
> [    2.411470]  process_one_work+0x1e0/0x330
> [    2.415478]  worker_thread+0x238/0x460
> [    2.419225]  kthread+0x128/0x130
> [    2.422452]  ret_from_fork+0x10/0x1c
> [    2.426195] ti_am3359-tscadc: probe of 40210000.tscadc failed with error -1

That's because of the way the cells are being registered:

        err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
                tscadc->used_cells, NULL, 0, NULL);

The cells are not numbered (tscadc->cells->id is always 0) and you are
forcing the use of the platform ID from the parent platform device
(with pdev->id here).  Instead you should s/pdev->id/PLATFORM_DEVID_AUTO/
or number the cells manually. I suggest the former.

> >> Signed-off-by: Vignesh R <vigneshr@ti.com>
> >> ---
> >>  drivers/mfd/ti_am335x_tscadc.c | 6 ++++--
> >>  1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
> >> index c2d47d78705b..ee08af34f81d 100644
> >> --- a/drivers/mfd/ti_am335x_tscadc.c
> >> +++ b/drivers/mfd/ti_am335x_tscadc.c
> >> @@ -248,7 +248,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
> >>  	if (tsc_wires > 0) {
> >>  		tscadc->tsc_cell = tscadc->used_cells;
> >>  		cell = &tscadc->cells[tscadc->used_cells++];
> >> -		cell->name = "TI-am335x-tsc";
> >> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
> >> +					    dev_name(&pdev->dev), "tsc");
> >>  		cell->of_compatible = "ti,am3359-tsc";
> >>  		cell->platform_data = &tscadc;
> >>  		cell->pdata_size = sizeof(tscadc);
> >> @@ -258,7 +259,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
> >>  	if (adc_channels > 0) {
> >>  		tscadc->adc_cell = tscadc->used_cells;
> >>  		cell = &tscadc->cells[tscadc->used_cells++];
> >> -		cell->name = "TI-am335x-adc";
> >> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
> >> +					    dev_name(&pdev->dev), "adc");
> >>  		cell->of_compatible = "ti,am3359-adc";
> >>  		cell->platform_data = &tscadc;
> >>  		cell->pdata_size = sizeof(tscadc);
> > 
> 

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 1/2] mfd: ti_am335x_tscadc: Provide unique name for child mfd cells

[Vignesh R]

On 28/11/18 4:33 PM, Lee Jones wrote:
> On Wed, 28 Nov 2018, Vignesh R wrote:
> 
>> Hi,
>>
>> On 28/11/18 2:37 PM, Lee Jones wrote:
>>> On Mon, 19 Nov 2018, Vignesh R wrote:
>>>
>>>> Provide unique names for child mfd cells, this is required in order to
>>>> support registering of multiple instances of same ti_am335x_tscadc IP.
>>>
>>> I don't think it is.  What is the error you are receiving?
>>
>> W/o this patch I get:
>>
>> [    2.296839] sysfs: cannot create duplicate filename '/bus/platform/devices/TI-am335x-adc'
>> [    2.305085] CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 4.20.0-rc3-next-20181123-00018-g
>> 7791ce8f123f-dirty #182
>> [    2.315254] Hardware name: Texas Instruments AM654 Base Board (DT)
>> [    2.321447] Workqueue: events deferred_probe_work_func
>> [    2.326585] Call trace:
>> [    2.329036]  dump_backtrace+0x0/0x1c0
>> [    2.332699]  show_stack+0x14/0x20
>> [    2.336017]  dump_stack+0x9c/0xbc
>> [    2.339333]  sysfs_warn_dup+0x60/0x78
>> [    2.342995]  sysfs_do_create_link_sd.isra.0+0xdc/0xe8
>> [    2.348042]  sysfs_create_link+0x20/0x40
>> [    2.351963]  bus_add_device+0x68/0x130
>> [    2.355711]  device_add+0x398/0x618
>> [    2.359199]  platform_device_add+0x120/0x290
>> [    2.363469]  mfd_add_device+0x23c/0x2e8
>> [    2.367302]  mfd_add_devices+0xb4/0x158
>> [    2.371136]  ti_tscadc_probe+0x35c/0x4c8
>> [    2.375056]  platform_drv_probe+0x50/0xa0
>> [    2.379062]  really_probe+0x204/0x2a8
>> [    2.382722]  driver_probe_device+0x58/0x100
>> [    2.386903]  __device_attach_driver+0x98/0xf0
>> [    2.391258]  bus_for_each_drv+0x64/0xc8
>> [    2.395091]  __device_attach+0xd8/0x138
>> [    2.398923]  device_initial_probe+0x10/0x18
>> [    2.403103]  bus_probe_device+0x90/0x98
>> [    2.406938]  deferred_probe_work_func+0x74/0xb0
>> [    2.411470]  process_one_work+0x1e0/0x330
>> [    2.415478]  worker_thread+0x238/0x460
>> [    2.419225]  kthread+0x128/0x130
>> [    2.422452]  ret_from_fork+0x10/0x1c
>> [    2.426195] ti_am3359-tscadc: probe of 40210000.tscadc failed with error -1
> 
> That's because of the way the cells are being registered:
> 
>         err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
>                 tscadc->used_cells, NULL, 0, NULL);
> 
> The cells are not numbered (tscadc->cells->id is always 0) and you are
> forcing the use of the platform ID from the parent platform device
> (with pdev->id here).  Instead you should s/pdev->id/PLATFORM_DEVID_AUTO/
> or number the cells manually. I suggest the former.
> 

Using PLATFORM_DEVID_AUTO works fine. I will post v2 with this change.
Thanks for the suggestion!

Regards
Vignesh

>>>> Signed-off-by: Vignesh R <vigneshr@ti.com>
>>>> ---
>>>>  drivers/mfd/ti_am335x_tscadc.c | 6 ++++--
>>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
>>>> index c2d47d78705b..ee08af34f81d 100644
>>>> --- a/drivers/mfd/ti_am335x_tscadc.c
>>>> +++ b/drivers/mfd/ti_am335x_tscadc.c
>>>> @@ -248,7 +248,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>>>>  	if (tsc_wires > 0) {
>>>>  		tscadc->tsc_cell = tscadc->used_cells;
>>>>  		cell = &tscadc->cells[tscadc->used_cells++];
>>>> -		cell->name = "TI-am335x-tsc";
>>>> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
>>>> +					    dev_name(&pdev->dev), "tsc");
>>>>  		cell->of_compatible = "ti,am3359-tsc";
>>>>  		cell->platform_data = &tscadc;
>>>>  		cell->pdata_size = sizeof(tscadc);
>>>> @@ -258,7 +259,8 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
>>>>  	if (adc_channels > 0) {
>>>>  		tscadc->adc_cell = tscadc->used_cells;
>>>>  		cell = &tscadc->cells[tscadc->used_cells++];
>>>> -		cell->name = "TI-am335x-adc";
>>>> +		cell->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s:%s",
>>>> +					    dev_name(&pdev->dev), "adc");
>>>>  		cell->of_compatible = "ti,am3359-adc";
>>>>  		cell->platform_data = &tscadc;
>>>>  		cell->pdata_size = sizeof(tscadc);
>>>
>>
> 

-- 
Regards
Vignesh

Re: [PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

[Jonathan Cameron]

On Wed, 28 Nov 2018 09:14:32 +0000
Lee Jones <lee.jones@linaro.org> wrote:

> On Mon, 19 Nov 2018, Vignesh R wrote:
> 
> > When performing single ended measurements with TSCADC, its recommended
> > to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the
> > corresponding STEP_CONFIGx register.
> > Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0)
> > reference voltage for ADC step needs to be set to VREFP and VREFN
> > respectively in STEP_CONFIGx register.
> > Without these changes, there may be variation of as much as ~2% in the
> > ADC's digital output which is bad for precise measurement.
> > 
> > Signed-off-by: Vignesh R <vigneshr@ti.com>
> > ---
> >  drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-  
> 
> >  include/linux/mfd/ti_am335x_tscadc.h | 4 ++++  
> 
> Acked-by: Lee Jones <lee.jones@linaro.org>
> 
I'll leave this for v2 given changes in the first patch.

My assumption is at the moment that both will go through mfd.
Shout Lee if you have other plans.

Jonathan

Re: [PATCH 2/2] iio: adc: ti_am335x_tscadc: Improve accuracy of measurement

[Lee Jones]

On Sat, 01 Dec 2018, Jonathan Cameron wrote:

> On Wed, 28 Nov 2018 09:14:32 +0000
> Lee Jones <lee.jones@linaro.org> wrote:
> 
> > On Mon, 19 Nov 2018, Vignesh R wrote:
> > 
> > > When performing single ended measurements with TSCADC, its recommended
> > > to set negative input (SEL_INM_SWC_3_0) of ADC step to ADC's VREFN in the
> > > corresponding STEP_CONFIGx register.
> > > Also, the positive(SEL_RFP_SWC_2_0) and negative(SEL_RFM_SWC_1_0)
> > > reference voltage for ADC step needs to be set to VREFP and VREFN
> > > respectively in STEP_CONFIGx register.
> > > Without these changes, there may be variation of as much as ~2% in the
> > > ADC's digital output which is bad for precise measurement.
> > > 
> > > Signed-off-by: Vignesh R <vigneshr@ti.com>
> > > ---
> > >  drivers/iio/adc/ti_am335x_adc.c      | 5 ++++-  
> > 
> > >  include/linux/mfd/ti_am335x_tscadc.h | 4 ++++  
> > 
> > Acked-by: Lee Jones <lee.jones@linaro.org>
> > 
> I'll leave this for v2 given changes in the first patch.
> 
> My assumption is at the moment that both will go through mfd.
> Shout Lee if you have other plans.

I'm fine with that.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
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