Re: [PATCH] arm64: dts: qcom: sc7280: Add touchscreen to villager
From: Konrad Dybcio
Date: Tue May 24 2022 - 18:42:02 EST
On 25/05/2022 00:14, Doug Anderson wrote:
Hi,
On Tue, May 24, 2022 at 2:13 PM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxx> wrote:
On 24/05/2022 22:48, Douglas Anderson wrote:
This adds the touchscreen to the sc7280-herobrine-villager device
tree. Note that the touchscreen on villager actually uses the reset
line and thus we use the more specific "elan,ekth6915" compatible
which allows us to specify the reset.
The fact that villager's touchscreen uses the reset line can be
contrasted against the touchscreen for CRD/herobrine-r1. On those
boards, even though the touchscreen goes to the display, it's not
hooked up to anything there.
In order to keep the line parked on herobrine/CRD, we'll move the
pullup from the qcard.dtsi file to the specific boards. This allows us
to disable the pullup in the villager device tree since the pin is an
output.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
This uses bindings introduced in the patch ("dt-bindings: HID:
i2c-hid: elan: Introduce bindings for Elan eKTH6915") [1].
[1] https://lore.kernel.org/r/20220523142257.v2.1.Iedc61f9ef220a89af6a031200a7850a27a440134@changeid
.../boot/dts/qcom/sc7280-herobrine-crd.dts | 11 ++++++++
.../qcom/sc7280-herobrine-herobrine-r1.dts | 11 ++++++++
.../dts/qcom/sc7280-herobrine-villager-r0.dts | 25 +++++++++++++++++++
arch/arm64/boot/dts/qcom/sc7280-qcard.dtsi | 1 -
4 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine-crd.dts b/arch/arm64/boot/dts/qcom/sc7280-herobrine-crd.dts
index a4ac33c4fd59..b79d84d7870a 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine-crd.dts
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine-crd.dts
@@ -134,6 +134,17 @@ &sdhc_2 {
status = "okay";
};
+/* PINCTRL - ADDITIONS TO NODES IN PARENT DEVICE TREE FILES */
Please drop this line, this isn't msm-3.4. It's immediately obvious that
if a pin is referenced by a label and it is not defined in this file
(because otherwise it wouldn't be both defined and referenced here..),
it comes from a previously included device tree.
In general these headings specify a change in sort ordering. Without
them then either we intersperse pinctrl overrides with other stuff,
which IMO is overall worse or people have no idea why the sort
ordering changes.
I get what you mean, but at the end of the day, the entire machine DT
specifies all machine-specific changes and only machine-specific
changes. They all are a part of a bigger picture, sometimes being
downstream from the SoC, sometimes downstream from a common board. I
don't think it brings much benefit if at all to separate them into
sections like these, if in the end they all correspond to modifications
present in the hardware. In its current form, the sorting is all over
the place, and ideally we could have labels sorted alphabetically.
The present solution, in my opinion, causes more disarray as you first
have to think about what is the change against and then find it in the
corresponding subsection instead of thinking of it as a complete
quote-on-quote diff against the parent DTSIs. Plus, most DTs don't split
it like that.
@@ -604,7 +604,6 @@ ts_int_conn: ts-int-conn {
ts_rst_conn: ts-rst-conn {
pins = "gpio54";
function = "gpio";
- bias-pull-up;
If you overwrite it where it should be overwritten, wouldn't it make
more sense to leave bias-pull-up here as a default configuration for
boards that don't have a peculiar routed-but-NC line?
Yeah, it'd be nice. ...but because of the way "bias" is specified in
the device tree it means an ugly "/delete-property" in places that
actually route the line. I believe that, style wise, the preference is
to avoid delete-property and move the bias toward board files in cases
like this. Bjorn can feel free to override me if he disagrees.
Ok, totally fair, it somehow slipped my mind that you have to delete one
property to replace it with the other, I retract that comment then.
Konrad
-Doug