Re: [PATCH v2] staging: greybus: Use gpio_is_valid()

[Arvind Yadav]

On Wednesday 02 May 2018 02:13 PM, Johan Hovold wrote:
> On Sat, Apr 28, 2018 at 10:05:39AM +0530, Arvind Yadav wrote:
> > Replace the manual validity checks for the GPIO with the
> > gpio_is_valid().
> >
> > Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
> > ---
> > chnage in v2 :
> >               Returning invalid gpio as error instead of -ENODEV.
> >
> >   drivers/staging/greybus/arche-platform.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c
> > index 83254a7..c3a7da5 100644
> > --- a/drivers/staging/greybus/arche-platform.c
> > +++ b/drivers/staging/greybus/arche-platform.c
> > @@ -448,7 +448,7 @@ static int arche_platform_probe(struct platform_device *pdev)
> >   	arche_pdata->svc_reset_gpio = of_get_named_gpio(np,
> >   							"svc,reset-gpio",
> >   							0);
> > -	if (arche_pdata->svc_reset_gpio < 0) {
> > +	if (!gpio_is_valid(arche_pdata->svc_reset_gpio)) {
> >   		dev_err(dev, "failed to get reset-gpio\n");
> >   		return arche_pdata->svc_reset_gpio;
> I'm sorry, but I don't this change is desirable. of_get_named_gpio()
> returns a valid gpio number or a negative errno, so there's no need to
> use the legacy gpio_is_valid() helper here.
>
> If you grep for of_get_named_gpio() you'll find that some drivers indeed
> use that helper this way, but they are in a clear minority.
>
> And ultimately, we want to move to using gpio descriptors anyway.

We need to check gpio validity. If we are using of_get_named_gpio() or not.
of_get_name_gpio() will read a device node and fetch the value. But 
it'll not
check that gpio is valid or not valid.
> >   	}
> > @@ -468,7 +468,7 @@ static int arche_platform_probe(struct platform_device *pdev)
> >   	arche_pdata->svc_sysboot_gpio = of_get_named_gpio(np,
> >   							  "svc,sysboot-gpio",
> >   							  0);
> > -	if (arche_pdata->svc_sysboot_gpio < 0) {
> > +	if (!gpio_is_valid(arche_pdata->svc_sysboot_gpio)) {
> >   		dev_err(dev, "failed to get sysboot gpio\n");
> >   		return arche_pdata->svc_sysboot_gpio;
> >   	}
> > @@ -487,7 +487,7 @@ static int arche_platform_probe(struct platform_device *pdev)
> >   	arche_pdata->svc_refclk_req = of_get_named_gpio(np,
> >   							"svc,refclk-req-gpio",
> >   							0);
> > -	if (arche_pdata->svc_refclk_req < 0) {
> > +	if (!gpio_is_valid(arche_pdata->svc_refclk_req)) {
> >   		dev_err(dev, "failed to get svc clock-req gpio\n");
> >   		return arche_pdata->svc_refclk_req;
> >   	}
> But if this were to be changed, you'd need to update also the fourth
> call to of_get_named_gpio() in this function.

Sorry, I missed it. Thanks for point out. I will add check for this.

~arvind
> Thanks,
> Johan