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* [PATCH V5 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5
       [not found] <1616071180-24493-1-git-send-email-kgunda@codeaurora.org>
@ 2021-03-18 12:39 ` Kiran Gunda
  2021-03-22 17:34   ` Lee Jones
  2021-03-18 12:39 ` [PATCH V5 2/2] backlight: qcom-wled: Correct the sync_toggle sequence Kiran Gunda
  1 sibling, 1 reply; 4+ messages in thread
From: Kiran Gunda @ 2021-03-18 12:39 UTC (permalink / raw)
  To: bjorn.andersson, jingoohan1, lee.jones, b.zolnierkie, dri-devel,
	daniel.thompson, jacek.anaszewski, pavel, robh+dt, mark.rutland,
	linux-leds, devicetree, linux-kernel, phone-devel, Andy Gross,
	linux-arm-msm, linux-fbdev
  Cc: Kiran Gunda

Currently, for WLED5, the FSC (Full scale current) setting is not
updated properly due to driver toggling the wrong register after
an FSC update.

On WLED5 we should only toggle the MOD_SYNC bit after a brightness
update. For an FSC update we need to toggle the SYNC bits instead.

Fix it by adopting the common wled3_sync_toggle() for WLED5 and
introducing new code to the brightness update path to compensate.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/video/backlight/qcom-wled.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index fc8b443..e9fbe24 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -348,7 +348,7 @@ static int wled3_sync_toggle(struct wled *wled)
 	return rc;
 }
 
-static int wled5_sync_toggle(struct wled *wled)
+static int wled5_mod_sync_toggle(struct wled *wled)
 {
 	int rc;
 	u8 val;
@@ -445,10 +445,23 @@ static int wled_update_status(struct backlight_device *bl)
 			goto unlock_mutex;
 		}
 
-		rc = wled->wled_sync_toggle(wled);
-		if (rc < 0) {
-			dev_err(wled->dev, "wled sync failed rc:%d\n", rc);
-			goto unlock_mutex;
+		if (wled->version < 5) {
+			rc = wled->wled_sync_toggle(wled);
+			if (rc < 0) {
+				dev_err(wled->dev, "wled sync failed rc:%d\n", rc);
+				goto unlock_mutex;
+			}
+		} else {
+			/*
+			 * For WLED5 toggling the MOD_SYNC_BIT updates the
+			 * brightness
+			 */
+			rc = wled5_mod_sync_toggle(wled);
+			if (rc < 0) {
+				dev_err(wled->dev, "wled mod sync failed rc:%d\n",
+					rc);
+				goto unlock_mutex;
+			}
 		}
 	}
 
@@ -1459,7 +1472,7 @@ static int wled_configure(struct wled *wled)
 		size = ARRAY_SIZE(wled5_opts);
 		*cfg = wled5_config_defaults;
 		wled->wled_set_brightness = wled5_set_brightness;
-		wled->wled_sync_toggle = wled5_sync_toggle;
+		wled->wled_sync_toggle = wled3_sync_toggle;
 		wled->wled_cabc_config = wled5_cabc_config;
 		wled->wled_ovp_delay = wled5_ovp_delay;
 		wled->wled_auto_detection_required =
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
 a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH V5 2/2] backlight: qcom-wled: Correct the sync_toggle sequence
       [not found] <1616071180-24493-1-git-send-email-kgunda@codeaurora.org>
  2021-03-18 12:39 ` [PATCH V5 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5 Kiran Gunda
@ 2021-03-18 12:39 ` Kiran Gunda
  2021-03-23  9:40   ` Lee Jones
  1 sibling, 1 reply; 4+ messages in thread
From: Kiran Gunda @ 2021-03-18 12:39 UTC (permalink / raw)
  To: bjorn.andersson, jingoohan1, lee.jones, b.zolnierkie, dri-devel,
	daniel.thompson, jacek.anaszewski, pavel, robh+dt, mark.rutland,
	linux-leds, devicetree, linux-kernel, phone-devel, Andy Gross,
	linux-arm-msm, linux-fbdev
  Cc: Kiran Gunda

As per the current implementation, after FSC (Full Scale Current)
and brightness update the sync bits are set-then-cleared.
But, the FSC and brightness sync takes place when the sync bits are
set (e.g. on a rising edge). So the hardware team recommends a
clear-then-set approach in order to guarantee such a transition
regardless of the previous register state.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/video/backlight/qcom-wled.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index e9fbe24..7c02f87 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -337,13 +337,13 @@ static int wled3_sync_toggle(struct wled *wled)
 
 	rc = regmap_update_bits(wled->regmap,
 				wled->sink_addr + WLED3_SINK_REG_SYNC,
-				mask, mask);
+				mask, WLED3_SINK_REG_SYNC_CLEAR);
 	if (rc < 0)
 		return rc;
 
 	rc = regmap_update_bits(wled->regmap,
 				wled->sink_addr + WLED3_SINK_REG_SYNC,
-				mask, WLED3_SINK_REG_SYNC_CLEAR);
+				mask, mask);
 
 	return rc;
 }
@@ -353,17 +353,17 @@ static int wled5_mod_sync_toggle(struct wled *wled)
 	int rc;
 	u8 val;
 
-	val = (wled->cfg.mod_sel == MOD_A) ? WLED5_SINK_REG_SYNC_MOD_A_BIT :
-					     WLED5_SINK_REG_SYNC_MOD_B_BIT;
 	rc = regmap_update_bits(wled->regmap,
 				wled->sink_addr + WLED5_SINK_REG_MOD_SYNC_BIT,
-				WLED5_SINK_REG_SYNC_MASK, val);
+				WLED5_SINK_REG_SYNC_MASK, 0);
 	if (rc < 0)
 		return rc;
 
+	val = (wled->cfg.mod_sel == MOD_A) ? WLED5_SINK_REG_SYNC_MOD_A_BIT :
+					     WLED5_SINK_REG_SYNC_MOD_B_BIT;
 	return regmap_update_bits(wled->regmap,
 				  wled->sink_addr + WLED5_SINK_REG_MOD_SYNC_BIT,
-				  WLED5_SINK_REG_SYNC_MASK, 0);
+				  WLED5_SINK_REG_SYNC_MASK, val);
 }
 
 static int wled_ovp_fault_status(struct wled *wled, bool *fault_set)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
 a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH V5 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5
  2021-03-18 12:39 ` [PATCH V5 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5 Kiran Gunda
@ 2021-03-22 17:34   ` Lee Jones
  0 siblings, 0 replies; 4+ messages in thread
From: Lee Jones @ 2021-03-22 17:34 UTC (permalink / raw)
  To: Kiran Gunda
  Cc: bjorn.andersson, jingoohan1, b.zolnierkie, dri-devel,
	daniel.thompson, jacek.anaszewski, pavel, robh+dt, mark.rutland,
	linux-leds, devicetree, linux-kernel, phone-devel, Andy Gross,
	linux-arm-msm, linux-fbdev

On Thu, 18 Mar 2021, Kiran Gunda wrote:

> Currently, for WLED5, the FSC (Full scale current) setting is not
> updated properly due to driver toggling the wrong register after
> an FSC update.
> 
> On WLED5 we should only toggle the MOD_SYNC bit after a brightness
> update. For an FSC update we need to toggle the SYNC bits instead.
> 
> Fix it by adopting the common wled3_sync_toggle() for WLED5 and
> introducing new code to the brightness update path to compensate.
> 
> Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
>  drivers/video/backlight/qcom-wled.c | 25 +++++++++++++++++++------
>  1 file changed, 19 insertions(+), 6 deletions(-)

Applied, thanks.

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

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH V5 2/2] backlight: qcom-wled: Correct the sync_toggle sequence
  2021-03-18 12:39 ` [PATCH V5 2/2] backlight: qcom-wled: Correct the sync_toggle sequence Kiran Gunda
@ 2021-03-23  9:40   ` Lee Jones
  0 siblings, 0 replies; 4+ messages in thread
From: Lee Jones @ 2021-03-23  9:40 UTC (permalink / raw)
  To: Kiran Gunda
  Cc: bjorn.andersson, jingoohan1, b.zolnierkie, dri-devel,
	daniel.thompson, jacek.anaszewski, pavel, robh+dt, mark.rutland,
	linux-leds, devicetree, linux-kernel, phone-devel, Andy Gross,
	linux-arm-msm, linux-fbdev

On Thu, 18 Mar 2021, Kiran Gunda wrote:

> As per the current implementation, after FSC (Full Scale Current)
> and brightness update the sync bits are set-then-cleared.
> But, the FSC and brightness sync takes place when the sync bits are
> set (e.g. on a rising edge). So the hardware team recommends a
> clear-then-set approach in order to guarantee such a transition
> regardless of the previous register state.
> 
> Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> ---
>  drivers/video/backlight/qcom-wled.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)

Applied, thanks.

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

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-03-23  9:41 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2021-03-18 12:39 ` [PATCH V5 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5 Kiran Gunda
2021-03-22 17:34   ` Lee Jones
2021-03-18 12:39 ` [PATCH V5 2/2] backlight: qcom-wled: Correct the sync_toggle sequence Kiran Gunda
2021-03-23  9:40   ` Lee Jones

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