On 2021-02-26 22:56, Daniel Thompson wrote:
On Fri, Feb 26, 2021 at 05:42:24PM +0530, Kiran Gunda wrote:
As per the current implementation, after FSC (Full Scale Current)
and brightness update the sync bits are transitioned from 1 to 0.
This still seems to incorrectly describe the current behaviour.
Surely in most cases (i.e. every time except the first) the value of
the
sync bit is 0 when the function is called and we get both a 0 to 1
and then a 1 to 0 transition.
That is why I recommended set-then-clear terminology to describe the
current behaviour. It is concise and correct.
Daniel.
Okay. Actually I have mentioned the "clear-and-set" in explaining the
fix.
Let me modify the same terminology in explaining the problem case also.
But, the FSC and brightness 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.
Signed-off-by: Kiran Gunda <kgu...@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)
--
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Forum,
a Linux Foundation Collaborative Project
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