[PATCH v2 0/2] tscadc: Couple of fixes

[PATCH v2 0/2] tscadc: Couple of fixes

[Vignesh R]

Couple of fixes for tscadc drivers that I found while adding support for
new SoC.


Vignesh R (2):
  mfd: ti_am335x_tscadc: Use PLATFORM_DEVID_AUTO while registering 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       | 5 +++--
 include/linux/mfd/ti_am335x_tscadc.h | 4 ++++
 3 files changed, 11 insertions(+), 3 deletions(-)

-- 
2.19.2

[PATCH v2 1/2] mfd: ti_am335x_tscadc: Use PLATFORM_DEVID_AUTO while registering mfd cells

[Vignesh R]

Use PLATFORM_DEVID_AUTO to number mfd cells while registering, so that
different instances are uniquely identified. 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>
---
v2: use PLATFORM_DEVID_AUTO as suggested by Lee Jones

 drivers/mfd/ti_am335x_tscadc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index c2d47d78705b..fd111296b959 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -264,8 +264,9 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
 		cell->pdata_size = sizeof(tscadc);
 	}
 
-	err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
-			tscadc->used_cells, NULL, 0, NULL);
+	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
+			      tscadc->cells, tscadc->used_cells, NULL,
+			      0, NULL);
 	if (err < 0)
 		goto err_disable_clk;
 
-- 
2.19.2

[PATCH v2 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>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
---

v2: No change

 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)
-- 
2.19.2

[GIT PULL] Immutable branch between MFD and IIO due for the v4.21 merge window

[Lee Jones]

Enjoy!

The following changes since commit 651022382c7f8da46cb4872a545ee1da6d097d2a:

  Linux 4.20-rc1 (2018-11-04 15:37:52 -0800)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git ib-mfd-iio-v4.21

for you to fetch changes up to 4b3ab9372ffa569827c8f7b7ffc7b69ba544a3bd:

  iio: adc: ti_am335x_tscadc: Improve accuracy of measurement (2018-12-03 11:33:20 +0000)

----------------------------------------------------------------
Immutable branch between MFD and IIO due for the v4.21 merge window

----------------------------------------------------------------
Vignesh R (2):
      mfd: ti_am335x_tscadc: Use PLATFORM_DEVID_AUTO while registering 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       | 5 +++--
 include/linux/mfd/ti_am335x_tscadc.h | 4 ++++
 3 files changed, 11 insertions(+), 3 deletions(-)
 
-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v2 1/2] mfd: ti_am335x_tscadc: Use PLATFORM_DEVID_AUTO while registering mfd cells

[Lee Jones]

On Mon, 03 Dec 2018, Vignesh R wrote:

> Use PLATFORM_DEVID_AUTO to number mfd cells while registering, so that
> different instances are uniquely identified. 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>
> ---
> v2: use PLATFORM_DEVID_AUTO as suggested by Lee Jones
> 
>  drivers/mfd/ti_am335x_tscadc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Applied, thanks.

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