# \[PATCH V2 1/2\] backlight: qcom-wled: Fix FSC update issue for WLED5 - Subsystems: FRAMEBUFFER LAYER, ARM/QUALCOMM MAILING LIST, BACKLIGHT CLASS/SUBSYSTEM, THE REST - Maintainers: Helge Deller, Lee Jones, Daniel Thompson, Jingoo Han, Linus Torvalds - Status: SUPERSEDED (Superseded by v5 posted 2021-03-18) - Superseded by v5 (posted 2021-03-18). - Revision v2 (5 revisions archived). - List: linux-fbdev - 2 messages, 2 authors - Page: https://ratatoskr.run/linux-fbdev/2021/02/6280011/t ## \[PATCH V2 1/2\] backlight: qcom-wled: Fix FSC update issue for WLED5 - From: Kiran Gunda \ - Date: 2021-02-26 12:14:11 - Message: https://ratatoskr.run/linux-fbdev/2021/02/6280011.md ```text 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 --- 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 ``` ## Re: \[PATCH V2 1/2\] backlight: qcom-wled: Fix FSC update issue for WLED5 - From: Daniel Thompson \ - Date: 2021-02-26 17:10:26 - Message: https://ratatoskr.run/linux-fbdev/2021/02/6280242.md ```text On Fri, Feb 26, 2021 at 05:42:23PM +0530, 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 Reviewed-by: Daniel Thompson Daniel. > --- > 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 > ```