On Wed, 15 Sep 2021 09:48:47 +0200
Miquel Raynal [off-list ref] wrote:

Hi Jonathan,

jic23@kernel.org wrote on Sun, 5 Sep 2021 14:13:32 +0100:

quoted

On Thu,  2 Sep 2021 23:51:24 +0200
Miquel Raynal [off-list ref] wrote:
  

quoted

Use the FIELD_PREP() macro when relevant. Sometimes reorder the lines to
be able to use the relevant bitmask.

Mind the s/%d/%ld/ change in a log due to the type change following the
use of FIELD_PREP() in the header.

Suggested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>    

What you have here is fine, but I would take it a step further and push the
FIELD_PREP() calls directly inline in the code.  There is little advantage
beyond saving a few characters in

STEPENB(3)

rather than

FIELD_PREP(STEPENB_MASK, 3)

If you don't want to go that far this is still an improvement so
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
  

quoted

---
 drivers/iio/adc/ti_am335x_adc.c      |  2 +-
 include/linux/mfd/ti_am335x_tscadc.h | 31 ++++++++++++++--------------
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index e946903b0993..54c410b6ca07 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c

@@ -126,7 +126,7 @@ static void tiadc_step_config(struct iio_dev *indio_dev)
 		chan = adc_dev->channel_line[i];
 
 		if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
-			dev_warn(dev, "chan %d step_avg truncating to %d\n",
+			dev_warn(dev, "chan %d step_avg truncating to %ld\n",
 				 chan, STEPCONFIG_AVG_16);
 			adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
 		}

diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index 4de16fc3d74f..29095c0dc6d8 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h

@@ -8,6 +8,7 @@
 #ifndef __LINUX_TI_AM335X_TSCADC_MFD_H
 #define __LINUX_TI_AM335X_TSCADC_MFD_H
 
+#include <linux/bitfield.h>
 #include <linux/mfd/core.h>
 
 #define REG_RAWIRQSTATUS	0x024

@@ -40,7 +41,7 @@
 
 /* Step Enable */
 #define STEPENB_MASK		GENMASK(16, 0)
-#define STEPENB(val)		((val) << 0)
+#define STEPENB(val)		FIELD_PREP(STEPENB_MASK, (val))    

My inclination with these is to drop the macro entirely and
just use FIELD_PREP(STEPENB_MASK, xxx) inline directly.
There is no loss of clarity in doing so and it gets you to a state
where you only have one macro per field which is nice for checking
purposes.  

Actually I don't like too much leaking FIELD_PREP()s directly in the
code because (and this is really a personal feeling) I found them
rather less straightforward to understand than a good old BIT() for
example. Moreover, I've already hacked in a lot of different
places and moving these definitions in the code directly would
produce a big diff, overall hardening possible future git-blames.

However, I rather agree on the fact that there is no point in defining
a mask and then using that mask in another macro unless that mask is
reused somewhere else. So if it's fine for you, I'll provide a new
version with a reduced number of defines in this file. Would this work
for you?

That will be fine.

Thanks,

Jonathan

quoted

quoted

 #define ENB(val)		BIT(val)
 #define STPENB_STEPENB		STEPENB(GENMASK(16, 0))
 #define STPENB_STEPENB_TC	STEPENB(GENMASK(12, 0))

@@ -58,11 +59,11 @@
 
 /* Step Configuration */
 #define STEPCONFIG_MODE_MASK	GENMASK(1, 0)
-#define STEPCONFIG_MODE(val)	((val) << 0)
+#define STEPCONFIG_MODE(val)	FIELD_PREP(STEPCONFIG_MODE_MASK, (val))
 #define STEPCONFIG_MODE_SWCNT	STEPCONFIG_MODE(1)
 #define STEPCONFIG_MODE_HWSYNC	STEPCONFIG_MODE(2)
 #define STEPCONFIG_AVG_MASK	GENMASK(4, 2)
-#define STEPCONFIG_AVG(val)	((val) << 2)
+#define STEPCONFIG_AVG(val)	FIELD_PREP(STEPCONFIG_AVG_MASK, (val))
 #define STEPCONFIG_AVG_16	STEPCONFIG_AVG(4)
 #define STEPCONFIG_XPP		BIT(5)
 #define STEPCONFIG_XNN		BIT(6)

@@ -70,43 +71,43 @@
 #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	GENMASK(13, 12)
+#define STEPCONFIG_RFP(val)	FIELD_PREP(STEPCONFIG_RFP_VREFP, (val))
 #define STEPCONFIG_INM_MASK	GENMASK(18, 15)
-#define STEPCONFIG_INM(val)	((val) << 15)
+#define STEPCONFIG_INM(val)	FIELD_PREP(STEPCONFIG_INM_MASK, (val))
 #define STEPCONFIG_INM_ADCREFM	STEPCONFIG_INM(8)
 #define STEPCONFIG_INP_MASK	GENMASK(22, 19)
-#define STEPCONFIG_INP(val)	((val) << 19)
+#define STEPCONFIG_INP(val)	FIELD_PREP(STEPCONFIG_INP_MASK, (val))
 #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	GENMASK(24, 23)
+#define STEPCONFIG_RFM(val)	FIELD_PREP(STEPCONFIG_RFM_VREFN, (val))
 
 /* Delay register */
 #define STEPDELAY_OPEN_MASK	GENMASK(17, 0)
-#define STEPDELAY_OPEN(val)	((val) << 0)
+#define STEPDELAY_OPEN(val)	FIELD_PREP(STEPDELAY_OPEN_MASK, (val))
 #define STEPCONFIG_OPENDLY	STEPDELAY_OPEN(0x098)
 #define STEPDELAY_SAMPLE_MASK	GENMASK(31, 24)
-#define STEPDELAY_SAMPLE(val)	((val) << 24)
+#define STEPDELAY_SAMPLE(val)	FIELD_PREP(STEPDELAY_SAMPLE_MASK, (val))
 #define STEPCONFIG_SAMPLEDLY	STEPDELAY_SAMPLE(0)
 
 /* Charge Config */
 #define STEPCHARGE_RFP_MASK	GENMASK(14, 12)
-#define STEPCHARGE_RFP(val)	((val) << 12)
+#define STEPCHARGE_RFP(val)	FIELD_PREP(STEPCHARGE_RFP_MASK, (val))
 #define STEPCHARGE_RFP_XPUL	STEPCHARGE_RFP(1)
 #define STEPCHARGE_INM_MASK	GENMASK(18, 15)
-#define STEPCHARGE_INM(val)	((val) << 15)
+#define STEPCHARGE_INM(val)	FIELD_PREP(STEPCHARGE_INM_MASK, (val))
 #define STEPCHARGE_INM_AN1	STEPCHARGE_INM(1)
 #define STEPCHARGE_INP_MASK	GENMASK(22, 19)
-#define STEPCHARGE_INP(val)	((val) << 19)
+#define STEPCHARGE_INP(val)	FIELD_PREP(STEPCHARGE_INP_MASK, (val))
 #define STEPCHARGE_RFM_MASK	GENMASK(24, 23)
-#define STEPCHARGE_RFM(val)	((val) << 23)
+#define STEPCHARGE_RFM(val)	FIELD_PREP(STEPCHARGE_RFM_MASK, (val))
 #define STEPCHARGE_RFM_XNUR	STEPCHARGE_RFM(1)
 
 /* Charge delay */
 #define CHARGEDLY_OPEN_MASK	GENMASK(17, 0)
-#define CHARGEDLY_OPEN(val)	((val) << 0)
+#define CHARGEDLY_OPEN(val)	FIELD_PREP(CHARGEDLY_OPEN_MASK, (val))
 #define CHARGEDLY_OPENDLY	CHARGEDLY_OPEN(0x400)
 
 /* Control register */

@@ -115,7 +116,7 @@
 #define CNTRLREG_STEPCONFIGWRT	BIT(2)
 #define CNTRLREG_POWERDOWN	BIT(4)
 #define CNTRLREG_AFE_CTRL_MASK	GENMASK(6, 5)
-#define CNTRLREG_AFE_CTRL(val)	((val) << 5)
+#define CNTRLREG_AFE_CTRL(val)	FIELD_PREP(CNTRLREG_AFE_CTRL_MASK, (val))
 #define CNTRLREG_4WIRE		CNTRLREG_AFE_CTRL(1)
 #define CNTRLREG_5WIRE		CNTRLREG_AFE_CTRL(2)
 #define CNTRLREG_8WIRE		CNTRLREG_AFE_CTRL(3)    

Thanks,
Miquèl