diff mbox series

[v3,2/4] arm64: dts: qcom: sc7180: revert "arm64: dts: qcom: sc7180: Avoid glitching SPI CS at bootup on trogdor"

Message ID 20221019001351.1630089-3-krzysztof.kozlowski@linaro.org
State New
Headers
Series arm64/pinctrl: dt-bindings: qcom: sc7180: convert to dtschema |

Commit Message

Krzysztof Kozlowski Oct. 19, 2022, 12:13 a.m. UTC 
  This reverts commit e440e30e26dd6b0424002ad0ddcbbcea783efd85 because it
is not a reliable way of fixing SPI CS glitch and it depends on specific
Linux kernel pin controller driver behavior.

This behavior of kernel driver was changed in commit b991f8c3622c
("pinctrl: core: Handling pinmux and pinconf separately") thus
effectively the DTS fix stopped being effective.

Proper solution for the glitching SPI chip select must be implemented in
the drivers, not via ordering of entries in DTS.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Changes since v2:
1. New patch

Not tested on hardware.

Cc: Doug Anderson <dianders@chromium.org>
---
 arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 27 +++-----------------
 1 file changed, 3 insertions(+), 24 deletions(-)

Comments

Doug Anderson Oct. 19, 2022, 3:48 p.m. UTC | #1 
Hi,

On Tue, Oct 18, 2022 at 5:14 PM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> This reverts commit e440e30e26dd6b0424002ad0ddcbbcea783efd85 because it
> is not a reliable way of fixing SPI CS glitch and it depends on specific
> Linux kernel pin controller driver behavior.
>
> This behavior of kernel driver was changed in commit b991f8c3622c
> ("pinctrl: core: Handling pinmux and pinconf separately") thus
> effectively the DTS fix stopped being effective.
>
> Proper solution for the glitching SPI chip select must be implemented in
> the drivers, not via ordering of entries in DTS.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>
> ---
>
> Changes since v2:
> 1. New patch
>
> Not tested on hardware.
>
> Cc: Doug Anderson <dianders@chromium.org>
> ---
>  arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 27 +++-----------------
>  1 file changed, 3 insertions(+), 24 deletions(-)

It would have been nice for the commit message to mention the fix in
the driver, which has already landed as commit d21f4b7ffc22 ("pinctrl:
qcom: Avoid glitching lines when we first mux to output").

In any case:

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

I've confirmed that this patch is fine after taking the pinctrl fix.

Tested-by: Douglas Anderson <dianders@chromium.org>
Krzysztof Kozlowski Oct. 20, 2022, 10:44 p.m. UTC | #2 
On 19/10/2022 11:48, Doug Anderson wrote:
> Hi,
> 
> On Tue, Oct 18, 2022 at 5:14 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> This reverts commit e440e30e26dd6b0424002ad0ddcbbcea783efd85 because it
>> is not a reliable way of fixing SPI CS glitch and it depends on specific
>> Linux kernel pin controller driver behavior.
>>
>> This behavior of kernel driver was changed in commit b991f8c3622c
>> ("pinctrl: core: Handling pinmux and pinconf separately") thus
>> effectively the DTS fix stopped being effective.
>>
>> Proper solution for the glitching SPI chip select must be implemented in
>> the drivers, not via ordering of entries in DTS.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>
>> ---
>>
>> Changes since v2:
>> 1. New patch
>>
>> Not tested on hardware.
>>
>> Cc: Doug Anderson <dianders@chromium.org>
>> ---
>>  arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 27 +++-----------------
>>  1 file changed, 3 insertions(+), 24 deletions(-)
> 
> It would have been nice for the commit message to mention the fix in
> the driver, which has already landed as commit d21f4b7ffc22 ("pinctrl:
> qcom: Avoid glitching lines when we first mux to output").

I'll add it.

> 
> In any case:
> 
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> 
> I've confirmed that this patch is fine after taking the pinctrl fix.
> 
> Tested-by: Douglas Anderson <dianders@chromium.org>

Awesome!

Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
index eae22e6e97c1..8f6e19bd6a99 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi
@@ -880,17 +880,17 @@  &sdhc_2 {
 };
 
 &spi0 {
-	pinctrl-0 = <&qup_spi0_cs_gpio_init_high>, <&qup_spi0_cs_gpio>;
+	pinctrl-0 = <&qup_spi0_cs_gpio>;
 	cs-gpios = <&tlmm 37 GPIO_ACTIVE_LOW>;
 };
 
 &spi6 {
-	pinctrl-0 = <&qup_spi6_cs_gpio_init_high>, <&qup_spi6_cs_gpio>;
+	pinctrl-0 = <&qup_spi6_cs_gpio>;
 	cs-gpios = <&tlmm 62 GPIO_ACTIVE_LOW>;
 };
 
 ap_spi_fp: &spi10 {
-	pinctrl-0 = <&qup_spi10_cs_gpio_init_high>, <&qup_spi10_cs_gpio>;
+	pinctrl-0 = <&qup_spi10_cs_gpio>;
 	cs-gpios = <&tlmm 89 GPIO_ACTIVE_LOW>;
 
 	cros_ec_fp: ec@0 {
@@ -1422,27 +1422,6 @@  pinconf {
 		};
 	};
 
-	qup_spi0_cs_gpio_init_high: qup-spi0-cs-gpio-init-high {
-		pinconf {
-			pins = "gpio37";
-			output-high;
-		};
-	};
-
-	qup_spi6_cs_gpio_init_high: qup-spi6-cs-gpio-init-high {
-		pinconf {
-			pins = "gpio62";
-			output-high;
-		};
-	};
-
-	qup_spi10_cs_gpio_init_high: qup-spi10-cs-gpio-init-high {
-		pinconf {
-			pins = "gpio89";
-			output-high;
-		};
-	};
-
 	qup_uart3_sleep: qup-uart3-sleep {
 		pinmux {
 			pins = "gpio38", "gpio39",