The MT7621 MIPS-based SOC contains an sdhci unit that is
much the same as the units supported by mtk-sd.c.
These patches enhance the driver so that I can use it on my MT7621
board (gnubee.org).
Some thoughts:
- I wonder if voltage-ranges should be a standard option, processed
by mmc_of_parse(), rather than requiring mmc_of_parse_voltage()
to be called as well?
- the "compatible" name "ralink,mt7620-sdhci" doesn't fit the pattern
of other names. It is a name I found in openwrt - I was previously
using a driver from there. I have no objection to changing it,
but I have no way to determine what the "correct" name it.
- I have tested the card-detect logic but not the write-protect, as
that doesn't seem to be wired on this board.
- My SOC doesn't have software-controlled clocks (that I can find).
To get the clocks that the driver requires, I define a "fixed-clock"
with the appropriate frequency and use that for both "source" and
"hclk". Many these clocks should be optional - at least hclk ??
- I don't need to reconfigure the pins for "uhs" so I just use the
same pinctrl setting for "default" and for "state_uhs". Maybe
"state_uhs" should be optional?
For reference, excerpts from my dts file are below.
Thanks,
NeilBrown
mmc_clock: mmc_clock@0 {
#clock-cells = <0>;
compatible = "fixed-clock";
clock-frequency = <48000000>;
};
and
sdhci: sdhci@1E130000 {
status = "disabled";
compatible = "ralink,mt7620-sdhci";
reg = <0x1E130000 0x4000>;
bus-width = <4>;
max-frequency = <48000000>;
cap-sd-highspeed;
cap-mmc-highspeed;
voltage-ranges = <2800 3300>;
pinctrl-names = "default", "state_uhs";
pinctrl-0 = <&sdhci_pins>;
pinctrl-1 = <&sdhci_pins>;
clocks = <&mmc_clock &mmc_clock>;
clock-names = "source", "hclk";
interrupt-parent = <&gic>;
interrupts = <GIC_SHARED 20 IRQ_TYPE_LEVEL_HIGH>;
};
---
NeilBrown (5):
mmc: mtk-sd: support "voltage-ranges" setting.
mmc: mtk-sd: don't hard-code interrupt trigger type
mmc: mtk-sd: add support for config found in mt7620 family SOCs.
mmc: mtk-sd: enable internal card-detect logic.
mmc: mtk-sd: enable internal write-protect logic.
Documentation/devicetree/bindings/mmc/mtk-sd.txt | 7 +
drivers/mmc/host/mtk-sd.c | 105 +++++++++++++++++++++-
2 files changed, 104 insertions(+), 8 deletions(-)
--
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