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    Subject[PATCH 5.7 007/166] ARM: dts: omap4-droid4: Fix spi configuration and increase rate
    Date
    From: Tony Lindgren <tony@atomide.com>

    [ Upstream commit 0df12a01f4857495816b05f048c4c31439446e35 ]

    We can currently sometimes get "RXS timed out" errors and "EOT timed out"
    errors with spi transfers.

    These errors can be made easy to reproduce by reading the cpcap iio
    values in a loop while keeping the CPUs busy by also reading /dev/urandom.

    The "RXS timed out" errors we can fix by adding spi-cpol and spi-cpha
    in addition to the spi-cs-high property we already have.

    The "EOT timed out" errors we can fix by increasing the spi clock rate
    to 9.6 MHz. Looks similar MC13783 PMIC says it works at spi clock rates
    up to 20 MHz, so let's assume we can pick any rate up to 20 MHz also
    for cpcap.

    Cc: maemo-leste@lists.dyne.org
    Cc: Merlijn Wajer <merlijn@wizzup.org>
    Cc: Pavel Machek <pavel@ucw.cz>
    Cc: Sebastian Reichel <sre@kernel.org>
    Signed-off-by: Tony Lindgren <tony@atomide.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi b/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
    index e39eee628afd6..08a7d3ce383f2 100644
    --- a/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
    +++ b/arch/arm/boot/dts/motorola-cpcap-mapphone.dtsi
    @@ -13,8 +13,10 @@
    #interrupt-cells = <2>;
    #address-cells = <1>;
    #size-cells = <0>;
    - spi-max-frequency = <3000000>;
    + spi-max-frequency = <9600000>;
    spi-cs-high;
    + spi-cpol;
    + spi-cpha;

    cpcap_adc: adc {
    compatible = "motorola,mapphone-cpcap-adc";
    --
    2.25.1


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