[PATCH V1 0/2] Fix WLED FSC Sync and brightness Sync settings

[PATCH V1 0/2] Fix WLED FSC Sync and brightness Sync settings

[Kiran Gunda]

The FSC (Full scale current) setting is not updated properly due to the
wrong register toggling for WLED5. Also the ILED_SYNC toggle and MOD_SYNC
toggle sequence is updated as per the hardware team recommendation to fix
the FSC update and brightness update issue.

Kiran Gunda (2):
  backlight: qcom-wled: Fix FSC update issue for WLED5
  backlight: qcom-wled: Correct the sync_toggle sequence

 drivers/video/backlight/qcom-wled.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
 a Linux Foundation Collaborative Project

[PATCH V1 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5

[Kiran Gunda]

Currently, for WLED5, after FSC register update MOD_SYNC_BIT
is toggled instead of SYNC_BIT. MOD_SYNC_BIT has to be toggled
after the brightness update and SYNC_BIT has to be toggled after
FSC update for WLED5. Fix it.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.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 3bc7800..aef52b9 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

[PATCH V1 2/2] backlight: qcom-wled: Correct the sync_toggle sequence

[Kiran Gunda]

Currently the FSC SYNC_BIT and MOD_SYNC_BIT are toggled
from 1 to 0 to update the FSC and brightenss settings.
Change this sequence form 0 to 1 as per the hardware team
recommendation to update the FSC and brightness correctly.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.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 aef52b9..19f83ac 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->ctrl_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->ctrl_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

Re: [PATCH V1 0/2] Fix WLED FSC Sync and brightness Sync settings

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 442 bytes --]

Hi!

> The FSC (Full scale current) setting is not updated properly due to the
> wrong register toggling for WLED5. Also the ILED_SYNC toggle and MOD_SYNC
> toggle sequence is updated as per the hardware team recommendation to fix
> the FSC update and brightness update issue.

If this is phone hardware, it might make sense to cc:
phone-devel@vger...

Best regards,
									Pavel

-- 
http://www.livejournal.com/~pavelmachek

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

Re: [PATCH V1 0/2] Fix WLED FSC Sync and brightness Sync settings

[kgunda]

On 2021-02-19 23:38, Pavel Machek wrote:
> Hi!
> 
>> The FSC (Full scale current) setting is not updated properly due to 
>> the
>> wrong register toggling for WLED5. Also the ILED_SYNC toggle and 
>> MOD_SYNC
>> toggle sequence is updated as per the hardware team recommendation to 
>> fix
>> the FSC update and brightness update issue.
> 
> If this is phone hardware, it might make sense to cc:
> phone-devel@vger...
> 
Yes. it is for phone hardware. Will cc the email.
> Best regards,
> 									Pavel

[PATCH V1 0/2] Fix WLED FSC Sync and brightness Sync settings

[Kiran Gunda]

The FSC (Full scale current) setting is not updated properly due to the
wrong register toggling for WLED5. Also the ILED_SYNC toggle and MOD_SYNC
toggle sequence is updated as per the hardware team recommendation to fix
the FSC update and brightness update issue.

Kiran Gunda (2):
  backlight: qcom-wled: Fix FSC update issue for WLED5
  backlight: qcom-wled: Correct the sync_toggle sequence

 drivers/video/backlight/qcom-wled.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
 a Linux Foundation Collaborative Project

[PATCH V1 2/2] backlight: qcom-wled: Correct the sync_toggle sequence

[Kiran Gunda]

Currently the FSC SYNC_BIT and MOD_SYNC_BIT are toggled
from 1 to 0 to update the FSC and brightenss settings.
Change this sequence form 0 to 1 as per the hardware team
recommendation to update the FSC and brightness correctly.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.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 aef52b9..19f83ac 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->ctrl_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->ctrl_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

Re: [PATCH V1 2/2] backlight: qcom-wled: Correct the sync_toggle sequence

[Daniel Thompson]

On Wed, Feb 24, 2021 at 09:20:48AM +0530, Kiran Gunda wrote:
> Currently the FSC SYNC_BIT and MOD_SYNC_BIT are toggled
> from 1 to 0 to update the FSC and brightenss settings.
> Change this sequence form 0 to 1 as per the hardware team
> recommendation to update the FSC and brightness correctly.

Again... this patch description feels somewhat rushed. A patch
description is there to support code reviewer and to go on the version
history to assist with future maintainance. They matter!

Anyhow I don't recognise the "from 1 to 0" in the code since both before
an after the change it goes "from 0 to 1" and "from 1 to 0" but in a
different order. Doesn't the code actually currently implement "set then
clear"? If so then, likewise the new code is adopting "clear then set".

As with patch 1, the sync bits modified by wled3_sync_toggle singular
or plural?

Finally a description that is more sympathetic to the reviewer would be
welcome.  For example the following (if my guess is right and it is
true) makes things much easier for the reviewer:

  "The sync takes place during a 0 to 1 transition of the sync
  bits so the hardware team recommends a clear-then-set approach in
  order to guarantee such a transition regardless of the previous
  register state".
 

Daniel.


> 
> Signed-off-by: Kiran Gunda <kgunda@codeaurora.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 aef52b9..19f83ac 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->ctrl_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->ctrl_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
> 

Re: [PATCH V1 2/2] backlight: qcom-wled: Correct the sync_toggle sequence

[kgunda]

On 2021-02-24 16:56, Daniel Thompson wrote:
> On Wed, Feb 24, 2021 at 09:20:48AM +0530, Kiran Gunda wrote:
>> Currently the FSC SYNC_BIT and MOD_SYNC_BIT are toggled
>> from 1 to 0 to update the FSC and brightenss settings.
>> Change this sequence form 0 to 1 as per the hardware team
>> recommendation to update the FSC and brightness correctly.
> 
> Again... this patch description feels somewhat rushed. A patch
> description is there to support code reviewer and to go on the version
> history to assist with future maintainance. They matter!
> 
> Anyhow I don't recognise the "from 1 to 0" in the code since both 
> before
> an after the change it goes "from 0 to 1" and "from 1 to 0" but in a
> different order. Doesn't the code actually currently implement "set 
> then
> clear"? If so then, likewise the new code is adopting "clear then set".
> 
I would have used "set" and "clear" instead of "0" and "1".
Yes. The current code implementation is "set" all SYN bits and then 
"clear"
all SYNC bits. The new code is modified to change the sequence from 
"clear"
first and then "set" to ensure both FSC and brightness are updated.

> As with patch 1, the sync bits modified by wled3_sync_toggle singular
> or plural?
It is plural. We have to "clear" and "set" all sync bits.
> 
> Finally a description that is more sympathetic to the reviewer would be
> welcome.  For example the following (if my guess is right and it is
> true) makes things much easier for the reviewer:
> Sure. I will update the documentation and patch description clearly.
>   "The sync takes place during a 0 to 1 transition of the sync
>   bits so the hardware team recommends a clear-then-set approach in
>   order to guarantee such a transition regardless of the previous
>   register state".
> 
> 
> Daniel.
> 
> 
>> 
>> Signed-off-by: Kiran Gunda <kgunda@codeaurora.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 aef52b9..19f83ac 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->ctrl_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->ctrl_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
>>