[PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[Nikita Yushchenko]

This adds nodes for lsm9ds0 sensor installed on the KF board.

With this patch, the sensor data becomes available over iio sysfs
interface.

Interrupt definition is not added yet, because the interrupt lines of
lsm9ds0 are pulled to VCC on the board, which implies need for
active-low configuration. But st_sensors drivers currently can't work
with active-low interrupts on this chip.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
 arch/arm64/boot/dts/renesas/ulcb-kf.dtsi | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi b/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
index a66301a4081d..d122e645a892 100644
--- a/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
+++ b/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
@@ -66,6 +66,13 @@ hdmi_3v3: regulator-hdmi-3v3 {
 		regulator-max-microvolt = <3300000>;
 	};
 
+	accel_3v3: regulator-acc-3v3 {
+		compatible = "regulator-fixed";
+		regulator-name = "accel-3v3";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+	};
+
 	hdmi1-out {
 		compatible = "hdmi-connector";
 		type = "a";
@@ -208,6 +215,22 @@ pcm3168a_endpoint_c: endpoint {
 					};
 				};
 			};
+
+			lsm9ds0_acc_mag@1d {
+				compatible = "st,lsm9ds0-imu";
+				reg = <0x1d>;
+
+				vdd-supply = <&accel_3v3>;
+				vddio-supply = <&accel_3v3>;
+			};
+
+			lsm9ds0_gyro@6b {
+				compatible = "st,lsm9ds0-gyro";
+				reg = <0x6b>;
+
+				vdd-supply = <&accel_3v3>;
+				vddio-supply = <&accel_3v3>;
+			};
 		};
 	};
 
-- 
2.30.2

Re: [PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[Geert Uytterhoeven]

Hi Nikita,

Thanks for your patch!

On Wed, Jan 12, 2022 at 9:52 PM Nikita Yushchenko
<nikita.yoush@cogentembedded.com> wrote:
> This adds nodes for lsm9ds0 sensor installed on the KF board.
>
> With this patch, the sensor data becomes available over iio sysfs
> interface.
>
> Interrupt definition is not added yet, because the interrupt lines of
> lsm9ds0 are pulled to VCC on the board, which implies need for
> active-low configuration. But st_sensors drivers currently can't work
> with active-low interrupts on this chip.

That's unfortunate, as DT describes hardware, not limitations of the
software stack.

> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>

> --- a/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
> +++ b/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
> @@ -66,6 +66,13 @@ hdmi_3v3: regulator-hdmi-3v3 {
>                 regulator-max-microvolt = <3300000>;
>         };
>
> +       accel_3v3: regulator-acc-3v3 {
> +               compatible = "regulator-fixed";
> +               regulator-name = "accel-3v3";
> +               regulator-min-microvolt = <3300000>;
> +               regulator-max-microvolt = <3300000>;
> +       };
> +
>         hdmi1-out {
>                 compatible = "hdmi-connector";
>                 type = "a";
> @@ -208,6 +215,22 @@ pcm3168a_endpoint_c: endpoint {
>                                         };
>                                 };
>                         };
> +
> +                       lsm9ds0_acc_mag@1d {

Please use standard node names: accelerometer@1d?

> +                               compatible = "st,lsm9ds0-imu";
> +                               reg = <0x1d>;
> +
> +                               vdd-supply = <&accel_3v3>;
> +                               vddio-supply = <&accel_3v3>;

According to the bindings, the supplies are not required, so you can
leave them out? Or are the bindings wrong?
(The bindings also say "interrupts: maxItems 2", while the "interrupts:
 description" says up to three interrupts, doh...)

> +                       };
> +
> +                       lsm9ds0_gyro@6b {

gyroscope@6b?

> +                               compatible = "st,lsm9ds0-gyro";
> +                               reg = <0x6b>;
> +
> +                               vdd-supply = <&accel_3v3>;
> +                               vddio-supply = <&accel_3v3>;
> +                       };
>                 };
>         };

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[Geert Uytterhoeven]

Hi Nikita,

On Wed, Jan 12, 2022 at 9:52 PM Nikita Yushchenko
<nikita.yoush@cogentembedded.com> wrote:
> This adds nodes for lsm9ds0 sensor installed on the KF board.
>
> With this patch, the sensor data becomes available over iio sysfs
> interface.
>
> Interrupt definition is not added yet, because the interrupt lines of
> lsm9ds0 are pulled to VCC on the board, which implies need for
> active-low configuration. But st_sensors drivers currently can't work
> with active-low interrupts on this chip.
>
> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>

Forgot something...

> --- a/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
> +++ b/arch/arm64/boot/dts/renesas/ulcb-kf.dtsi
> @@ -66,6 +66,13 @@ hdmi_3v3: regulator-hdmi-3v3 {
>                 regulator-max-microvolt = <3300000>;
>         };
>
> +       accel_3v3: regulator-acc-3v3 {

Please move up, to preserve sort order.

> +               compatible = "regulator-fixed";
> +               regulator-name = "accel-3v3";
> +               regulator-min-microvolt = <3300000>;
> +               regulator-max-microvolt = <3300000>;
> +       };
> +
>         hdmi1-out {
>                 compatible = "hdmi-connector";
>                 type = "a";
> @@ -208,6 +215,22 @@ pcm3168a_endpoint_c: endpoint {
>                                         };
>                                 };
>                         };
> +
> +                       lsm9ds0_acc_mag@1d {

Please move up, to preserve sort order.

> +                               compatible = "st,lsm9ds0-imu";
> +                               reg = <0x1d>;
> +
> +                               vdd-supply = <&accel_3v3>;
> +                               vddio-supply = <&accel_3v3>;
> +                       };

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[Nikita Yushchenko]

>> Interrupt definition is not added yet, because the interrupt lines of
>> lsm9ds0 are pulled to VCC on the board, which implies need for
>> active-low configuration. But st_sensors drivers currently can't work
>> with active-low interrupts on this chip.
> 
> That's unfortunate, as DT describes hardware, not limitations of the
> software stack.

Unfortunately, if interrupt definition is added, driver does wrong things and causes board hang.

>> +                               vdd-supply = <&accel_3v3>;
>> +                               vddio-supply = <&accel_3v3>;
> 
> According to the bindings, the supplies are not required, so you can
> leave them out? Or are the bindings wrong?

If supplies are not defined, warning messages about dummy regulator are logged.

> (The bindings also say "interrupts: maxItems 2", while the "interrupts:
>   description" says up to three interrupts, doh...)

Chip has 3 interrupt outputs. On KF board, all those are ANDed together and result connected to SoC's 
gpio that is expected to be used as a shared active-low interrupt. Driver currently claims that this 
chip does not support active-low interrupts. Per datasheet, this is not true. But driver's way to set up 
interrupt registers does not scale to the case when interrupts have to be configured by different bits 
in several registers, that part of the driver has to be somehow rewritten. I guess nobody has ever tried 
to make these drivers (st_*) to drive a compound device (accel+gyro) with interrupts.

At the same time, the device is perfectly useful without interrupts, and that is how it is enabled in 
the vendor BSP.

Nikita

Re: [PATCH] arm64: dts: renesas: ulcb-kf: add 9-asix sensor device

[Geert Uytterhoeven]

Hi Nikita,

On Wed, Jan 26, 2022 at 4:28 PM Nikita Yushchenko
<nikita.yoush@cogentembedded.com> wrote:
> >> Interrupt definition is not added yet, because the interrupt lines of
> >> lsm9ds0 are pulled to VCC on the board, which implies need for
> >> active-low configuration. But st_sensors drivers currently can't work
> >> with active-low interrupts on this chip.
> >
> > That's unfortunate, as DT describes hardware, not limitations of the
> > software stack.
>
> Unfortunately, if interrupt definition is added, driver does wrong things and causes board hang.

OK.

> >> +                               vdd-supply = <&accel_3v3>;
> >> +                               vddio-supply = <&accel_3v3>;
> >
> > According to the bindings, the supplies are not required, so you can
> > leave them out? Or are the bindings wrong?
>
> If supplies are not defined, warning messages about dummy regulator are logged.

OK.

> > (The bindings also say "interrupts: maxItems 2", while the "interrupts:
> >   description" says up to three interrupts, doh...)
>
> Chip has 3 interrupt outputs. On KF board, all those are ANDed together and result connected to SoC's
> gpio that is expected to be used as a shared active-low interrupt. Driver currently claims that this
> chip does not support active-low interrupts. Per datasheet, this is not true. But driver's way to set up
> interrupt registers does not scale to the case when interrupts have to be configured by different bits
> in several registers, that part of the driver has to be somehow rewritten. I guess nobody has ever tried
> to make these drivers (st_*) to drive a compound device (accel+gyro) with interrupts.
>
> At the same time, the device is perfectly useful without interrupts, and that is how it is enabled in
> the vendor BSP.

OK, will queue in renesas-devel for v5.18, with the low-hanging fruits
(node names, order) fixed.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds