To: Douglas Anderson <dianders@chromium.org>,
        Michal Simek <michal.simek@xilinx.com>,
        =?UTF-8?Q?S=c3=b6ren_Brinkmann?= <soren.brinkmann@xilinx.com>,
        Jerry Huang <Chang-Ming.Huang@freescale.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Adrian Hunter <adrian.hunter@intel.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>, Mason <slash.tmp@free.fr>
From: Sebastian Frias <sf84@laposte.net>
Subject: Adding a .platform_init callback to sdhci_arasan_ops
Message-ID: <d50dcd8a-2489-4e82-1dc7-13e93e38d5ff@laposte.net>
Date: Fri, 25 Nov 2016 16:24:02 +0100
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Hi,

When using the Arasan SDHCI HW IP, there is a set of parameters called
"Hardware initialized registers"

(Table 7, Section "Pin Signals", page 56 of Arasan "SD3.0/SDIO3.0/eMMC4.4
AHB Host Controller", revision 6.0 document)

In some platforms those signals are connected to registers that need to
be programmed at some point for proper driver/HW initialisation.

I found that the 'struct sdhci_ops' contains a '.platform_init' callback
that is called from within 'sdhci_pltfm_init', and that seems a good
candidate for a place to program those registers (*).

Do you agree?

Best regards,

Sebastian


(*): This has been prototyped on 4.7 as working properly.
However, upstream commit:

commit 3ea4666e8d429223fbb39c1dccee7599ef7657d5
Author: Douglas Anderson <dianders@chromium.org>
Date:   Mon Jun 20 10:56:47 2016 -0700

    mmc: sdhci-of-arasan: Properly set corecfg_baseclkfreq on rk3399
...

could affect this solution because of the way the 'sdhci_arasan_of_match'
struct is used after that commit.