On 09/25/2015 08:02 AM, Tomi Valkeinen wrote:
> LDO1 regulator (VDD_SD) is connected to SoC's vddshv8. vddshv8 needs to
> be kept always powered (see commit 5a0f93c6576a ("ARM: dts: Add
> am57xx-beagle-x15"), but at the moment VDD_SD is enabled/disabled
> depending on whether an SD card is inserted or not.
>
> This patch sets LDO1 regulator to always-on.
>
> This patch has a side effect of fixing another issue, HDMI DDC not
> working when SD card is not inserted:
>
> Why this happens is that the tpd12s015 (HDMI level shifter/ESD
> protection chip) has LS_OE GPIO input, which needs to be enabled for the
> HDMI DDC to work. LS_OE comes from gpio6_28. The pin that provides
> gpio6_28 is powered by vddshv8, and vddshv8 comes from VDD_SD.
>
> So when SD card is not inserted, VDD_SD is disabled, and LS_OE stays
> off.
>
> The proper fix for the HDMI DDC issue would be to maybe have the pinctrl
> framework manage the pin specific power.
>
> Apparently this fixes also a third issue (copy paste from Kishon's
> patch):
>
> ldo1_reg in addition to being connected to the io lines is also
> connected to the card detect line. On card removal, omap_hsmmc
> driver does a regulator_disable causing card detect line to be
> pulled down. This raises a card insertion interrupt and once the
> MMC core detects there is no card inserted, it does a
> regulator disable which again raises a card insertion interrupt.
> This happens in a loop causing infinite MMC interrupts.
>
> Fixes: 5a0f93c6576a ("ARM: dts: Add am57xx-beagle-x15")
> Cc: Kishon Vijay Abraham I <kishon@xxxxxx>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Reported-by: Louis McCarthy <compeoree@xxxxxxxxx>
Acked-by: Nishanth Menon <nm@xxxxxx>
> ---
> arch/arm/boot/dts/am57xx-beagle-x15.dts | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/am57xx-beagle-x15.dts b/arch/arm/boot/dts/am57xx-beagle-x15.dts
> index 3a05b94f59ed..ba8ef66a16e0 100644
> --- a/arch/arm/boot/dts/am57xx-beagle-x15.dts
> +++ b/arch/arm/boot/dts/am57xx-beagle-x15.dts
> @@ -415,11 +415,12 @@
> /* SMPS9 unused */
>
> ldo1_reg: ldo1 {
> - /* VDD_SD */
> + /* VDD_SD / VDDSHV8 */
> regulator-name = "ldo1";
> regulator-min-microvolt = <1800000>;
> regulator-max-microvolt = <3300000>;
> regulator-boot-on;
> + regulator-always-on;
> };
>
> ldo2_reg: ldo2 {
>
--
Regards,
Nishanth Menon
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