Hello,

On Mon, Dec 13, 2021 at 8:03 AM Rong Chen [off-list ref] wrote:

The patch will add a value of ocr supported by the controller,
to specify some of voltage values are supported.

Can you please share some details on this topic?

We already have many boards upstreamed which work fine without
manually setting ocr_avail in the driver.
In general there's two types of boards:
1) boards where the regulator can switch between different voltages.
One example is the Odroid-C2, see meson-gxbb-odroidc2.dts [0]
Here we specify:
  vmmc-supply = <&tflash_vdd>;
  vqmmc-supply = <&tf_io>;
&tflash_vdd is either turned off or at 3.3V when turned on.
&tf_io can be either turned off, 1.8V or 3.3V.

2) boards where the voltages are fixed.
One example is Radxa Zero, see meson-g12a-radxa-zero.dts [1]
For the SD card the board uses:
  vmmc-supply = <&vddao_3v3>;
  vqmmc-supply = <&vddao_3v3>;
(meaning fixed 3.3V always-on power source for both VMMC and VQMMC)
and for eMMC the board uses:
  vmmc-supply = <&vcc_3v3>;
  vqmmc-supply = <&vcc_1v8>;
(meaning: 3.3V always-on power source for vmmc and 1.8V always-on
power source for VQMMC)

With the information from the regulators the MMC core will
automatically detect ocr_avail in Linux.
Or in other words: your .dts may be missing the link between regulator
and MMC controller vmmc/vqmmc.
Can you please double-check this?


Best regards,
Martin


[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/amlogic/meson-gxbb-odroidc2.dts?id=2585cf9dfaaddf00b069673f27bb3f8530e2039c#n354
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/amlogic/meson-g12a-radxa-zero.dts?id=2585cf9dfaaddf00b069673f27bb3f8530e2039c#n333

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