Subject: arasan,sdhci.txt "compatibility" DT binding

From: [email-masked] (Mason)
Date: Mon, 28 Nov 2016 16:44:39 +0100

Hello,

@Shawn Lin, could you take a look below and tell me exactly
which IP core(s) Rockchip is using in its SoCs?

Based on the feedback I received, here is an updated list of
compatible strings and controller versions dealt with by the
drivers/mmc/host/sdhci-of-arasan.c code.

Xilinx Zynq:
"SD2.0 / SDIO2.0 / MMC3.31 AHB Host Controller"
"arasan,sdhci-8.9a"
NB: 8.9a is the documentation revision (dated 2011-10-19)
subsequent tweaks labeled 9.0a, 9.1a, 9.2a

Xilinx ZynqMP:
"SD3.0 / SDIO3.0 / eMMC4.51 AHB Host Controller"
"arasan,sdhci-8.9a"
NB: using the same compatible string as Zynq

Sigma SMP87xx
"SD3.0 / SDIO3.0 / eMMC4.4 AHB Host Controller"
no compatible string yet, platform-specific init required

APM:
"SD3.0 / SDIO3.0 / eMMC4.41 AHB Host Controller"
"arasan,sdhci-4.9a"
NB: 4.9a appears to be the documentation revision
no functional diff with "arasan,sdhci-8.9a"

Rockchip
Exact IP unknown, waiting for Shawn's answer
"arasan,sdhci-5.1"
NB: 5.1 appears to refer to the eMMC standard supported

On a final note, there are many variations of the Arasan IP.
I've tracked down at least the following:

SD_2.0_SDIO_2.0__MMC_3.31_AHB_Host_Controller.pdf
SD_3.0_SDIO_3.0_eMMC_4.41_OCP_Host_Controller.pdf
SD_3.0_SDIO_3.0_eMMC_4.4__AHB_Host_Controller.pdf
SD_3.0_SDIO_3.0_eMMC_4.51_Host_Controller.pdf
SD_3.0_SDIO_3.0_eMMC_4.5__Host_Controller.pdf
SD_4.1_SDIO_4.1_eMMC_4.51_Host_Controller.pdf
SD_4.1_SDIO_4.1_eMMC_5.1__Host_Controller.pdf

It seems to me the compatible string should specify
the SD/SDIO version AND the eMMC version, since it
seems many combinations are allowed, e.g. eMMC 4.51
has two possible SD versions.

What do you think?

Regards.