diff mbox series

[2/7] arm64: dts: qcom: sc7280: Add 3ms ramp to herobrine's pp3300_left_in_mlb

Message ID 20230206184744.2.I13814cefc5ab3e0a39ebd09f052e3fd25d4e8f1d@changeid
State New
Headers
Series arm: qcom: Fix touchscreen voltage for sc7280-herobrine boards |

Commit Message

Doug Anderson Feb. 7, 2023, 2:48 a.m. UTC 
  The "pp3300_left_in_mlb" rail on herobrine eventually connects up to
"vreg_edp_3p3" on the qcard. On several herobrine designs this rail
has been measured to need more than 1ms to turn on.

While technically a herobrine derivative (defined as anyone including
the "herobrine.dtsi") could change the board to make the rail rise
faster or slower, the fact that two boards (evoker and villager) both
measured it as taking more than 1ms implies that it's probably going
to be the norm. Thus, let's add a "regulator-enable-ramp-delay"
straight into the herobrine.dtsi to handle this. If a particular
derivative board needs a faster or slower one then they can override
it, though that feels unlikely.

While we measured something a bit over 1ms, we'll choose 3ms to give
us a tiny bit of margin. This isn't a rail that turns off and on all
the time anyway and 3ms is nothing compared to the total amount of
time to power on a panel.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi | 2 ++
 1 file changed, 2 insertions(+)

Comments

Matthias Kaehlcke Feb. 7, 2023, 6:15 p.m. UTC | #1 
On Mon, Feb 06, 2023 at 06:48:11PM -0800, Douglas Anderson wrote:
> The "pp3300_left_in_mlb" rail on herobrine eventually connects up to
> "vreg_edp_3p3" on the qcard. On several herobrine designs this rail
> has been measured to need more than 1ms to turn on.
> 
> While technically a herobrine derivative (defined as anyone including
> the "herobrine.dtsi") could change the board to make the rail rise
> faster or slower, the fact that two boards (evoker and villager) both
> measured it as taking more than 1ms implies that it's probably going
> to be the norm. Thus, let's add a "regulator-enable-ramp-delay"
> straight into the herobrine.dtsi to handle this. If a particular
> derivative board needs a faster or slower one then they can override
> it, though that feels unlikely.
> 
> While we measured something a bit over 1ms, we'll choose 3ms to give
> us a tiny bit of margin. This isn't a rail that turns off and on all
> the time anyway and 3ms is nothing compared to the total amount of
> time to power on a panel.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
index 27f479ff9d80..ded36b5d28c7 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
@@ -108,6 +108,8 @@  pp3300_left_in_mlb: pp3300-left-in-mlb-regulator {
 		pinctrl-names = "default";
 		pinctrl-0 = <&en_pp3300_dx_edp>;
 
+		regulator-enable-ramp-delay = <3000>;
+
 		vin-supply = <&pp3300_z1>;
 	};