diff mbox series

[v3,4/4] arm64: dts: qcom: qrb5165-rb5: switch into using GPIO for SPI0 CS

Message ID 20210209202849.1148569-5-dmitry.baryshkov@linaro.org
State New
Headers show
Series arm64: dts: qcom: qrb5165-rb5: use GPIO as SPI0 CS | expand

Commit Message

Dmitry Baryshkov Feb. 9, 2021, 8:28 p.m. UTC 
GENI SPI controller shows several issues if it manages the CS on its own
(see 37dd4b777942 ("arm64: dts: qcom: sc7180: Provide pinconf for SPI to
use GPIO for CS")) for the details. Configure SPI0 CS pin as a GPIO.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

---
 arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

-- 
2.30.0

Comments

Doug Anderson Feb. 9, 2021, 11:57 p.m. UTC | #1 
Hi,

On Tue, Feb 9, 2021 at 12:29 PM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>

> GENI SPI controller shows several issues if it manages the CS on its own

> (see 37dd4b777942 ("arm64: dts: qcom: sc7180: Provide pinconf for SPI to

> use GPIO for CS")) for the details. Configure SPI0 CS pin as a GPIO.


Slight nit that it might be nice to mention that (presumably) the only
reason this actually fixed any bugs for you is because you have extra
non-mainline patches to the SPI driver that (presumably) break
non-GPIO chip select.  If it's the same non-mainline patch that I
reviewed to add GPI/GSI support to the SPI driver then I'm not
terribly surprised.  I believe when I reviewed it I found that it was
breaking the non-GPI/GSI code paths.

See <https://lore.kernel.org/r/CAD=FV=XmfpQXhK_tKor-ta+5dqT-aq7OnV1e=VY-vMuXmUQEfQ@mail.gmail.com>
where I said "Why are you changing this?  [...] I'd imagine this
change breaks stuff?"

Really the only benefit from this change _should_ be better performance.


> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

> ---

>  arch/arm64/boot/dts/qcom/qrb5165-rb5.dts | 5 +++--

>  1 file changed, 3 insertions(+), 2 deletions(-)


Other than the nit about the CL desc:

Reviewed-by: Douglas Anderson <dianders@chromium.org>
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
index 922f329d623a..d329829c61fa 100644
--- a/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
+++ b/arch/arm64/boot/dts/qcom/qrb5165-rb5.dts
@@ -815,7 +815,7 @@  &pm8150_rtc {
 	status = "okay";
 };
 
-&qup_spi0_cs {
+&qup_spi0_cs_gpio {
 	drive-strength = <6>;
 	bias-disable;
 };
@@ -963,7 +963,8 @@  codec {
 &spi0 {
 	status = "okay";
 	pinctrl-names = "default";
-	pinctrl-0 = <&qup_spi0_data_clk>, <&qup_spi0_cs>;
+	pinctrl-0 = <&qup_spi0_data_clk>, <&qup_spi0_cs_gpio>;
+	cs-gpios = <&tlmm 31 GPIO_ACTIVE_LOW>;
 
 	can@0 {
 		compatible = "microchip,mcp2518fd";