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 [thread overview] 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
WARNING: multiple messages have this Message-ID (diff)
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 [thread overview] 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 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2021-03-01 16:15 UTC|newest] Thread overview: 6+ 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 ` 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 2021-03-01 16:10 ` Kiran Gunda [this message] 2021-03-01 16:10 ` [PATCH V4 2/2] backlight: qcom-wled: Correct the sync_toggle sequence Kiran Gunda
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