Phone-Devel Archive on lore.kernel.org.
 help / color / Atom feed
From: Kiran Gunda <kgunda@codeaurora.org>
To: bjorn.andersson@linaro.org, jingoohan1@gmail.com,
	lee.jones@linaro.org, b.zolnierkie@samsung.com,
	dri-devel@lists.freedesktop.org, daniel.thompson@linaro.org,
	jacek.anaszewski@gmail.com, pavel@ucw.cz, robh+dt@kernel.org,
	mark.rutland@arm.com, linux-leds@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andy Gross <agross@kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-fbdev@vger.kernel.org
Cc: phone-devel@vger.kernel.org, Kiran Gunda <kgunda@codeaurora.org>
Subject: [PATCH V4 2/2] backlight: qcom-wled: Correct the sync_toggle sequence
Date: Mon,  1 Mar 2021 21:40:30 +0530
Message-ID: <1614615030-12703-3-git-send-email-kgunda@codeaurora.org> (raw)
In-Reply-To: <1614615030-12703-1-git-send-email-kgunda@codeaurora.org>

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 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


      parent reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-01 16:10 [PATCH V4 0/2] Fix WLED FSC Sync and brightness Sync settings Kiran Gunda
2021-03-01 16:10 ` [PATCH V4 1/2] backlight: qcom-wled: Fix FSC update issue for WLED5 Kiran Gunda
2021-03-01 16:10 ` Kiran Gunda [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1614615030-12703-3-git-send-email-kgunda@codeaurora.org \
    --to=kgunda@codeaurora.org \
    --cc=agross@kernel.org \
    --cc=b.zolnierkie@samsung.com \
    --cc=bjorn.andersson@linaro.org \
    --cc=daniel.thompson@linaro.org \
    --cc=devicetree@vger.kernel.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jacek.anaszewski@gmail.com \
    --cc=jingoohan1@gmail.com \
    --cc=lee.jones@linaro.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-leds@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=pavel@ucw.cz \
    --cc=phone-devel@vger.kernel.org \
    --cc=robh+dt@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Phone-Devel Archive on lore.kernel.org.

Archives are clonable:
	git clone --mirror https://lore.kernel.org/phone-devel/0 phone-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 phone-devel phone-devel/ https://lore.kernel.org/phone-devel \
		phone-devel@vger.kernel.org
	public-inbox-index phone-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.phone-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git