Re: [PATCH 5/6] media: sun4i: Add H3 deinterlace driver

Jernej Škrabec
2019-09-12T20:43:36Z

Dne četrtek, 12. september 2019 ob 22:26:47 CEST je Maxime Ripard napisal(a):
> Hi,
>
> On Thu, Sep 12, 2019 at 07:51:31PM +0200, Jernej Skrabec wrote:
> > + dev->regmap = devm_regmap_init_mmio(dev->dev, dev->base,
> > +
&deinterlace_regmap_config);
> > + if (IS_ERR(dev->regmap)) {
> > + dev_err(dev->dev, "Couldn't create deinterlace
regmap\n");
> > +
> > + return PTR_ERR(dev->regmap);
> > + }
> > +
> > + ret = clk_prepare_enable(dev->bus_clk);
> > + if (ret) {
> > + dev_err(dev->dev, "Failed to enable bus clock\n");
> > +
> > + return ret;
> > + }
>
> Do you need to keep the bus clock enabled all the time? Usually, for
> the SoCs that have a reset line, you only need it to read / write to
> the registers, not to have the controller actually running.
>
> If you don't, then regmap_init_mmio_clk will take care of that for
> you.

I'll test that.

>
> > + clk_set_rate(dev->mod_clk, 300000000);
> > +
> > + ret = clk_prepare_enable(dev->mod_clk);
> > + if (ret) {
> > + dev_err(dev->dev, "Failed to enable mod clock\n");
> > +
> > + goto err_bus_clk;
> > + }
> > +
> > + ret = clk_prepare_enable(dev->ram_clk);
> > + if (ret) {
> > + dev_err(dev->dev, "Failed to enable ram clock\n");
> > +
> > + goto err_mod_clk;
> > + }
> > +
> > + ret = reset_control_reset(dev->rstc);
> > + if (ret) {
> > + dev_err(dev->dev, "Failed to apply reset\n");
> > +
> > + goto err_ram_clk;
> > + }
>
> This could be moved to a runtime_pm hook, with get_sync called in the
> open. That way you won't leave the device powered on if it's unused.

Ok.

>
> > +struct deinterlace_dev {
> > + struct v4l2_device v4l2_dev;
> > + struct video_device vfd;
> > + struct device *dev;
> > + struct v4l2_m2m_dev *m2m_dev;
> > +
> > + /* Device file mutex */
> > + struct mutex dev_mutex;
> > +
> > + void __iomem *base;
> > + struct regmap *regmap;
>
> Do you need to store the base address in that structure if you're
> using the regmap?

Probably not. I'll remove it in v2.

Best regards,
Jernej

>
> Maxime