Hi Fabio,
thanks for the fast reply.
On 05/30/2017 10:40 PM, Fabio Estevam wrote:
Hi Christopher,
On Tue, May 30, 2017 at 5:16 PM, <christopher.spinrath@xxxxxxxxxxxxxx> wrote:
+ awnh387_pwrseq: pwrseq {
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_pwrseq>;
+ compatible = "mmc-pwrseq-sd8787";
+ powerdown-gpios = <&gpio7 12 GPIO_ACTIVE_HIGH>;
+ reset-gpios = <&gpio6 16 GPIO_ACTIVE_HIGH>;
At least in the AW-NH387 datasheet I found it says:
RESETn: Reset(active low at least 10ns)
The BSP device tree uses an active-low regulator called nreset, too, but
strangly it has a startup delay of 10ms while the powerdown-regulator
"starts up" immediately.
(btw: the "regulator setup" is not able to handle resets correctly.)
It seems to me that the pwrseq-sd8787 uses inverted logic: it first sets
the -- in our case -- active-high gpio to high, waits, and then enables
the powerdown-gpio.
This coincides with the gpio being called "reset" in the pwrseq binding,
neither "nreset" nor "RESETn" (beware the missing *n*ot).
Please double check the polarity in device tree.
I just double checked: high/high for powerdown/reset gpios is the only
of the four possible combinations that works.
So, all in all, I think the polarity is correct (or either the pwrseq
driver or hardware invertes the polarity for some reason).
Cheers,
Christopher
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