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From:   Martin Kepplinger <martin.kepplinger@puri.sm>
To:     robh@kernel.org, mark.rutland@arm.com, shawnguo@kernel.org
Cc:     kernel@pengutronix.de, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Martin Kepplinger <martin.kepplinger@puri.sm>
Subject: [PATCH] arm64: dts: librem5-devkit: add lsm9ds1 mount matrix
Date:   Mon, 20 Jan 2020 11:07:22 +0100
Message-Id: <20200120100722.30359-1-martin.kepplinger@puri.sm>
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The IMU chip on the librem5-devkit is not mounted at the "natural" place
that would match normal phone orientation (see the documentation for the
details about what that is).

Since the lsm9ds1 driver supports providing a mount matrix, we can describe
the orientation on the board in the dts:

Create a right-handed coordinate system (x * -1; see the datasheet for the
axis) and rotate 180 degrees around the y axis because the device sits on
the back side from the display.

Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
---

tested on the librem5-devkit of course, finally fixing the orientation problem
for the accelerometer :)

thanks,

                            martin


 arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts b/arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts
index 703254282b96..6c8ab009081b 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5-devkit.dts
@@ -457,6 +457,9 @@
 		reg = <0x6a>;
 		vdd-supply = <&reg_3v3_p>;
 		vddio-supply = <&reg_3v3_p>;
+		mount-matrix =  "1",  "0",  "0",
+				"0",  "1",  "0",
+				"0",  "0", "-1";
 	};
 };
 
-- 
2.20.1