GPIO request failures for Renesas rcar-gen3

[Adam Ford]

I am trying to port U-Boot to a new product based on a Renesas RZ/G2M
(rcar-gen3).  We're have this working with Renesas' version from
2018.09, but I am trying to integrate it with U-Boot 2020.07-rc4

What's happening is that it seems like all GPIO are failing to be
requested, so things like regulator-gpio fail, reset-gpios, etc. all
return errors.

The dm tree and gpio status commands all appear to show gpio banks are
enumerating, but since nothing can use the GPIO's it seems like the
common thread is the gpio driver for the rcar3.

I was hoping someone might have some thoughts of things I could try or
investigate.  In order to properly set the voltage for the MMC card, I
need "regulator-gpio" to operate correctly.

The gpio regulator node looks like:

vccq_sdhi0: regulator-vccq-sdhi0 {
     compatible = "regulator-gpio";

     regulator-name = "SDHI0 VccQ";
     regulator-min-microvolt = <1800000>;
     regulator-max-microvolt = <3300000>;

     gpios = <&gpio6 30 GPIO_ACTIVE_HIGH>;
     gpios-states = <1>;
     states = <3300000 1>, <1800000 0>;
     regulator-always-on;
};

Log Below with some debugging turned on.

U-Boot 2020.07-rc4-00060-g9cb895203a-dirty (Jun 18 2020 - 15:27:00 -0500)

CPU: Renesas Electronics R8A7796 rev 2.1
Model: Beacon Embedded Works RZ/G2M Development Kit
DRAM:  3.9 GiB
Bank #0: 0x048000000 - 0x0bfffffff, 1.9 GiB
Bank #1: 0x600000000 - 0x67fffffff, 2 GiB

MMC:   gpio_request_tail: dm_gpio_requestf failed
gpio_request_tail: Node 'regulator-vccq-sdhi0', property 'gpios',
failed to request GPIO index 0: -19
regulator gpio - not found! Error: -19gpio_request_tail: Node
'regulator-vccq-sdhi0', property 'enable-gpios', failed to request
GPIO index 0: -2
gpio at e6055400: set_value: error: gpio gpio at e605540030 not reserved
Can't set regulator-gpio : regulator-vccq-sdhi0 gpio to: 1
gpio_request_tail: Node 'regulator0', property 'gpio', failed to
request GPIO index 0: -2
sd at ee100000: 0, sd at ee160000: 1
Loading Environment from MMC... gpio_request_tail: Node 'regulator1',
property 'gpio', failed to request GPIO index 0: -2
OK
In:    serial at e6e88000
Out:   serial at e6e88000
Err:   serial at e6e88000
Net:   gpio_request_tail: dm_gpio_requestf failed
gpio_request_tail: Node 'ethernet-phy at 0', property 'reset-gpios',
failed to request GPIO index 0: -19
gpio at e6052000: set_value: error: gpio gpio at e605200010 not reserved
gpio at e6052000: set_value: error: gpio gpio at e605200010 not reserved

Error: ethernet at e6800000 address not set.
No ethernet found.

Hit any key to stop autoboot:  0
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