[PATCH 0/3] r8a779f0: add SDHI support

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

These are the remaining patches to enable basic eMMC support on the
Renesas Spider board with a R-Car S4-8 SoC. The patches are based on
mmc/next.

Some comments:

- For reasons, I have not understood yet, the performance is a bit lower
  than our BSP when checksumming a 250MB file (BSP: 2.7s, this: 3.4s).
  I was investigating clock handling differences between BSP and upstream
  for a while because the values of the clock trees differed quite a
  lot. The patch "clk: renesas: rcar-gen4: implement SDSRC properly" was
  rejected which is fine with me. I meanwhile found out that the BSP had
  PLL4 entries missing which made the values all bogus. The newest
  version of the BSP fixed that. So, it doesn't seem to be the clocks.
  Back to the drawing board, let's handle this incrementally.

- I made prototypes to support the microSD slot despite it is hardly
  accessible because the Ethernet subboard is blocking the way. After
  further discussions with Shimoda-san, we agreed to not support it
  upstream because the voltage switching in hardware or CPLD is only
  for specific testing. I added a comment to describe that.

Other than that, eMMC works fine so far.

All the best,

   Wolfram


Wolfram Sang (3):
  clk: renesas: r8a779f0: Add sdh0 clock
  arm64: dts: renesas: r8a779f0: Add SDHI0 support
  arm64: dts: renesas: spider-cpu: enable eMMC0

 .../boot/dts/renesas/r8a779f0-spider-cpu.dtsi | 45 +++++++++++++++++++
 arch/arm64/boot/dts/renesas/r8a779f0.dtsi     | 13 ++++++
 drivers/clk/renesas/r8a779f0-cpg-mssr.c       |  3 +-
 3 files changed, 60 insertions(+), 1 deletion(-)

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2.35.1