[PATCH] regulator: fix: enable gpio when requested

Lukasz Majewski
2020-04-28T04:24:10Z

Hi Mark,

> The fix in commit b7adcdd073c0 has the side-effect that the regulator
> will be disabled when requesting the relevant gpio in
> regulator_common_ofdata_to_platdata() and enabled in
> regulator_pre_probe() when the regulator was already enabled.
> This leads to a short interruption in the 3.3V power to the PCIe
> slot on the firefly-rk3399 which makes an ADATA SX8000NP NVMe SSD
> unhappy.
>
> Fix this by setting the GPIOD_IS_OUT_ACTIVE flag again when the
> 'regulator-boot-on' property is set, but check for this property
> explicitly instead of relying on the "boot_on" member of
> the uclass platdata.
>
> Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
> ---
> drivers/power/regulator/regulator-uclass.c | 3 ---
> drivers/power/regulator/regulator_common.c | 2 ++
> 2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/power/regulator/regulator-uclass.c
> b/drivers/power/regulator/regulator-uclass.c index
> c9d26344d7..90961de95c 100644 ---
> a/drivers/power/regulator/regulator-uclass.c +++
> b/drivers/power/regulator/regulator-uclass.c @@ -464,9 +464,6 @@
> static int regulator_pre_probe(struct udevice *dev) (uc_pdata->min_uA
> == uc_pdata->max_uA)) uc_pdata->flags |= REGULATOR_FLAG_AUTOSET_UA;
>
> - if (uc_pdata->boot_on)
> - regulator_set_enable(dev, uc_pdata->boot_on);
> -
> return 0;
> }
>
> diff --git a/drivers/power/regulator/regulator_common.c
> b/drivers/power/regulator/regulator_common.c index
> 33b73b7c2f..bc13b88476 100644 ---
> a/drivers/power/regulator/regulator_common.c +++
> b/drivers/power/regulator/regulator_common.c @@ -17,6 +17,8 @@ int
> regulator_common_ofdata_to_platdata(struct udevice *dev,
> if (!dev_read_bool(dev, "enable-active-high"))
> flags |= GPIOD_ACTIVE_LOW;
> + if (dev_read_bool(dev, "regulator-boot-on"))
> + flags |= GPIOD_IS_OUT_ACTIVE;
>
> /* Get optional enable GPIO desc */
> gpio = &dev_pdata->gpio;

Sorry, but this is a simple revert of my commit and breaks use cases
described in the commit message of this fix.

Do you see some kind of "glitch" on the gpio in
regulator_common_of_platdata?

The regulator-boot-on property [1] shall prevent from the issue you
described in the commit message of this revert.

Links:
[1] -
https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/regulator/regulator.yaml#L40

Best regards,

Lukasz Majewski

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