sd-uhs-sdr104 setting in .dts file for i.MX6QP

[takayuki_ishii]

Hello community, 

I hope to know how register setting in "sdhci-esdhc-imx.c" if SDR104 card is inserted about delay line auto-tuning.

1. Which value does it set uSDHCx_MIX_CTRL register to enable auto tuning?

2. How set DLY_CELL_SET_XXXX bit in uSDHCx_CLK_TUNE_CTRL_STATUS register?

In Documentation/devicetree/bindings/mmc/mmc.txt, "sd-uhs-sdr104" is commented as following.

- sd-uhs-sdr104: SD UHS SDR104 speed is supported

3. Is it effect for usdhc in i.mx6xxx.dts file?

I look forward to hearing from you.

Best regards,

Ishii.

[jimmychan]

1. AUTO_TUNE_EN set to 1.

2. For the field description, you can refer to chapter 68.8.25 in reference manual. for the example code, you can refer to the esdhc_prepare_tuning() and esdhc_executing_tuning() in sdhci-esdhc-imx.c

3.According to the driver source code in sdhci-esdhc-imx.c, it should support SDR104. Do you meet any issue for this? if yes, is there any error message?

[takayuki_ishii]

Hello Jimmychan,

Thank you for your reply.

We hope to know how to setup a device tree file of uSDHC1 to enable SDR104 and delay line auto-tuning with CMD19.

We plan to use WiFi card with uSDHC1 of our i.MX6QP custom board.

Can I show some sample setting of uSDHC1 device tree to enable SDR104 and auto-tuning?

Best regards,

Ishii.

[jimmychan]

1. What's the Linux BSP version?

2. Have you tried the method mentioned in supporting SDR104 in imx6 board by yocto 

"For supporting SDR104, should change the dts file, because of 1.8v only, should remove no-1-8-v in the source code, then add vmmc-supply according to the dts file above."

3. Please add "sd-uhs-sdr104;" in the usdhc1 device node.

[takayuki_ishii]

Hello Jimmychan,

Thank you for your quick replay.

A1. Now we will be test it with Linux BSP L4.9.11, but finally we plan to use Android N7.1.2.

A2. Not yet. so we will try to it.

A3. OK, we will try to add "sd-uhs-sdr104" setting.

Best regards,

Ishii.