Can't access mmc #0 on mt7623 when booted from external SD

[David Woodhouse]

On Thu, 2020-06-18 at 16:52 +0100, David Woodhouse wrote:
> So... whose bug is that? :)

Looks like the pinctrl driver. This *ought* to work (with the caveat
that I really ought to make two pinctrl setups and change between them
according to the voltage, like the Linux DT and mtk-sd driver do).

--- a/arch/arm/dts/mt7623n-bananapi-bpi-r2.dts
+++ b/arch/arm/dts/mt7623n-bananapi-bpi-r2.dts
@@ -133,12 +133,14 @@
                               "MSDC0_DAT2", "MSDC0_DAT3",
"MSDC0_DAT4",
                               "MSDC0_DAT5", "MSDC0_DAT6",
"MSDC0_DAT7";
                        input-enable;
-                       bias-pull-up;
+                       drive-strength = <2>;
+                       bias-pull-up = <3>;
                };
 
                conf-clk {
                        pins = "MSDC0_CLK";
-                       bias-pull-down;
+                       drive-strength = <2>;
+                       bias-pull-down = <3>;
                };
 
                conf-rst {


But it doesn't work. Partly because the U-Boot mtk pinctrl driver
doesn't support the R0 R1 bits encoded in that <3>, and partly because
it doesn't *even* get pullup/pulldown right at all; it sets the bit in
the GPIO_PULLSEL registers but *not* the PUPD bit in the correct
register for MSDC and other pins.
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