Re: [PATCH 1/4] iio: adc: rockchip_saradc: reset saradc controller before programming it

[Caesar Wang]

On 2016å07æ26æ 17:00, John Keeping wrote:
> On Tue, 26 Jul 2016 14:11:47 +0800, Caesar Wang wrote:
>
> > SARADC controller needs to be reset before programming it, otherwise
> > it will not function properly.
> >
> > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>
> > Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> > Cc: Heiko Stuebner <heiko@xxxxxxxxx>
> > Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> > Cc: linux-iio@xxxxxxxxxxxxxxx
> > Cc: linux-rockchip@xxxxxxxxxxxxxxxxxxx
> > ---
> >
> > diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
> > index f9ad6c2..2f0e110 100644
> > --- a/drivers/iio/adc/rockchip_saradc.c
> > +++ b/drivers/iio/adc/rockchip_saradc.c
> > @@ -218,6 +231,13 @@ static int rockchip_saradc_probe(struct platform_device *pdev)
> >   	if (IS_ERR(info->regs))
> >   		return PTR_ERR(info->regs);
> >   
> > +	info->reset = devm_reset_control_get(&pdev->dev, "saradc-apb");
> > +	if (IS_ERR(info->reset)) {
> > +		ret = PTR_ERR(info->reset);
> > +		dev_err(&pdev->dev, "failed to get saradc reset: %d\n", ret);
> > +		return ret;
> > +	}
> Does this need to handle ENOENT so as to avoid failing with old device
> tree blobs?

I'm no sure why we have to support the old device tree,
We can apply this series patches if we need to support the reset property.
---

Maybe, I can follow you suggestion to handle the ENOENT, as following:

+ /*
+ * The reset should be an optional property, as it should work
+ * with old devicetrees as well
+ */
+ info->reset = devm_reset_control_get(&pdev->dev, "saradc-apb");
+ if (IS_ERR(info->reset)) {
+ if (PTR_ERR(info->reset) == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ return ret;
+ }
+ dev_dbg(&pdev->dev, "no reset control found\n");
+ info->reset = NULL;
+ }
...

+ if (info->reset)
+ rockchip_saradc_reset_controller(info->reset);
+

How about it?


-
Caesar
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--
caesar wang | software engineer | wxt@xxxxxxxxxxxxx