Re: [PATCH v2] ARM: dts: ux500: configure the accelerometers open drain

[Jonathan Cameron <jic23@kernel.org>]

On 14/04/16 09:48, Linus Walleij wrote:
> Configure the two accelerometers sharing GPIO line 82 as:
> 
> - Open drain so that they can share the same interrupt line.
> 
> Configure the corresponding interrupt pin:
> 
> - Trigger on the falling edge since open drain implies that we
>   do not actively drive the line high, but we will actively drive
>   it low to generate interrupts and then it moves from high to low
>   i.e. a falling edge.
> 
> - Pulled up so the line will be biased to high unless an IRQ
>   is active on any device on the line, and thus it goes high
>   again after the interrupt is deasserted.
> 
> Cc: linux-iio@vger.kernel.org
> Cc: Jonathan Cameron <jic23@cam.ac.uk>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
I have just applied the patch supporting this to the iio tree
for the next merge window.

Jonathan
> ---
> ChangeLog v1->v2:
> - Switch to using the drive-mode-open-drain; setting
> ---
>  arch/arm/boot/dts/ste-href-tvk1281618.dtsi | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/ste-href-tvk1281618.dtsi b/arch/arm/boot/dts/ste-href-tvk1281618.dtsi
> index 55f9d0cc90f3..aec816c8ecb6 100644
> --- a/arch/arm/boot/dts/ste-href-tvk1281618.dtsi
> +++ b/arch/arm/boot/dts/ste-href-tvk1281618.dtsi
> @@ -93,14 +93,15 @@
>  				/* Accelerometer */
>  				compatible = "st,lsm303dlh-accel";
>  				st,drdy-int-pin = <1>;
> +				drive-open-drain;
>  				reg = <0x18>;
>  				vdd-supply = <&ab8500_ldo_aux1_reg>;
>  				vddio-supply = <&db8500_vsmps2_reg>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&accel_tvk_mode>;
>  				interrupt-parent = <&gpio2>;
> -				interrupts = <18 IRQ_TYPE_EDGE_RISING>,
> -					     <19 IRQ_TYPE_EDGE_RISING>;
> +				interrupts = <18 IRQ_TYPE_EDGE_FALLING>,
> +					     <19 IRQ_TYPE_EDGE_FALLING>;
>  			};
>  			lsm303dlh@1e {
>  				/*
> @@ -118,14 +119,15 @@
>  				/* Accelerometer */
>  				compatible = "st,lis331dl-accel";
>  				st,drdy-int-pin = <1>;
> +				drive-open-drain;
>  				reg = <0x1c>;
>  				vdd-supply = <&ab8500_ldo_aux1_reg>;
>  				vddio-supply = <&db8500_vsmps2_reg>;
>  				pinctrl-names = "default";
>  				pinctrl-0 = <&accel_tvk_mode>;
>  				interrupt-parent = <&gpio2>;
> -				interrupts = <18 IRQ_TYPE_EDGE_RISING>,
> -					     <19 IRQ_TYPE_EDGE_RISING>;
> +				interrupts = <18 IRQ_TYPE_EDGE_FALLING>,
> +					     <19 IRQ_TYPE_EDGE_FALLING>;
>  			};
>  			ak8974@0f {
>  				/* Magnetometer */
> @@ -216,7 +218,7 @@
>  					/* Accelerometer interrupt lines 1 & 2 */
>  					tvk_cfg {
>  						pins = "GPIO82_C1", "GPIO83_D3";
> -						ste,config = <&gpio_in_pd>;
> +						ste,config = <&gpio_in_pu>;
>  					};
>  				};
>  			};
>