linux-kernel - Re: [PATCH] usb: phy: generic: request regulator optionally

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Date:   Tue, 06 Sep 2016 10:45:19 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Stefan Agner <stefan@...er.ch>
Cc:     gregkh@...uxfoundation.org, fabio.estevam@....com,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Stefan Agner <stefan@...er.ch>,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] usb: phy: generic: request regulator optionally


Mark,

Stefan Agner <stefan@...er.ch> writes:
> According to the device tree bindings the vcc-supply is optional.
> So far the driver did request the regulator using devm_regulator_get
> which creates a dummy regulator for convenience. Since we can have
> the supply unconnected, we should make use of the optional variant
> of the regulator call which does not return a dummy regulator but
> -ENODEV. The driver already has checks in case the regulator is an
> error pointer.
>
> Note that with this change the behavior is slightly different in
> case devm_regulator_get_optional returns -EPROBE_DEFER: The driver
> returns -EPROBE_DEFER even if needs_vcc is set false. This is the
> correct behavior, since even if the regulator is optional, it might
> get initialized later...
>
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
> This gets rid of warnings such as this (seen on i.MX 7):
> 30800000.aips-bus:usbphynop1 supply vcc not found, using dummy regulator
>
> --
> Stefan
>
>  drivers/usb/phy/phy-generic.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/phy/phy-generic.c b/drivers/usb/phy/phy-generic.c
> index 980c9de..38ceadc 100644
> --- a/drivers/usb/phy/phy-generic.c
> +++ b/drivers/usb/phy/phy-generic.c
> @@ -275,12 +275,12 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop,
>  		}
>  	}
>  
> -	nop->vcc = devm_regulator_get(dev, "vcc");
> +	nop->vcc = devm_regulator_get_optional(dev, "vcc");
>  	if (IS_ERR(nop->vcc)) {
>  		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
>  					PTR_ERR(nop->vcc));
> -		if (needs_vcc)
> -			return -EPROBE_DEFER;
> +		if (needs_vcc || PTR_ERR(nop->vcc) == -EPROBE_DEFER)
> +			return PTR_ERR(nop->vcc);

does this look okay from a regulator API perspective?

-- 
balbi

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