2017-11-03 11:29 GMT+08:00 Vincent Yang [off-list ref]:

2017-11-02 19:00 GMT+08:00 Ulf Hansson [off-list ref]:

quoted

+ Vincent Yang (several emails, don't know which works)

On 2 November 2017 at 11:49, Ard Biesheuvel [off-list ref] wrote:

quoted

On 2 November 2017 at 10:48, Ulf Hansson [off-list ref] wrote:

quoted

On 2 November 2017 at 01:12, Ard Biesheuvel [off-list ref] wrote:

quoted

On 2 November 2017 at 00:08, Rob Herring [off-list ref] wrote:

quoted

On Wed, Nov 01, 2017 at 12:21:32AM +0000, Ard Biesheuvel wrote:

quoted

The Socionext SynQuacer SoC inherits this IP from Fujitsu, but
requires the F_SDH30_CMD_DAT_DELAY bit to be set in the
F_SDH30_ESD_CONTROL control register.

So let's add an optional property to this device's binding, and
set the attribute if it is present in the DT node.

Signed-off-by: Ard Biesheuvel <redacted>
---
 Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt |  2 ++
 drivers/mmc/host/sdhci_f_sdh30.c                        | 18 +++++++++++++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt b/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt
index de2c53cff4f1..9ad02f743ad0 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-fujitsu.txt

@@ -15,6 +15,8 @@ Required properties:
 Optional properties:
 - vqmmc-supply: phandle to the regulator device tree node, mentioned
   as the VCCQ/VDD_IO supply in the eMMC/SD specs.
+- cmd-dat-delay-select: boolean property indicating that this host requires
+  the CMD_DAT_DELAY control to be enabled.

Needs a vendor prefix unless this is a standard SDHCI bit (in which
case it should be documented in a common spot).

I suspect this is a non-standard thing, so I'll add the fujitsu prefix. Ulf?

This is specific to the Fujitsu variant.

However, what puzzles me is why this bit is needed for the Socionext
SynQuacer SoC, but not for other SoCs that uses this IP. That seems
weird (probably wrong).

Moreover, the F_SDH30_CMD_DAT_DELAY register define is already there,
so I would rather suspect that it's something that did got fully
implemented. In other words, I don't think you need a new DT binding,
but rather try to implement it generically for the sdhci-f_sdh30
driver. Do you think that will work?

Do you mean set it unconditionally? That works for me, but I have no

Yes.

quoted

way of testing whether it still works on other SoCs that use this IP.

Me neither!

Hi all, I can not yet get contact with IP owner because it is a
holiday in Japan.
Around two years ago, F_SDH30_CMD_DAT_DELAY was a new feature of this IP.
I will update the latest information as soon as I get it.

I got a response from IP owner.
He explains F_SDH30_CMD_DAT_DELAY is intended to adjust signal timing of
CMD/DAT lines, and it is necessary to change its value according to
SoC/board design.
So he advises us to make F_SDH30_CMD_DAT_DELAY adjustable by a DT binding.

Kind regards
Vincent

quoted

Apparently there are no DTS in the kernel git that uses the
"fujitsu,mb86s70-sdhci-3.0".

Around two years ago, sdhci_f_sdh30_driver was a portion for mb86s70 SoC
patch series, but finally the patch series did not fully go upstream.

Kind regards
Vincent

quoted

I looped in Vincent Yang, let's hope he can provide us with some more
information.

Kind regards
Uffe

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