Re: [PATCH v8 07/34] clk: tegra: Support runtime PM and power domain

Thierry Reding
2021-08-18T16:42:20Z

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On Wed, Aug 18, 2021 at 06:05:21PM +0300, Dmitry Osipenko wrote:
> 18.08.2021 17:07, Thierry Reding пишет:
> > On Tue, Aug 17, 2021 at 04:27:27AM +0300, Dmitry Osipenko wrote:
> > [...]
> >> +struct clk *tegra_clk_register(struct clk_hw *hw)
> >> +{
> >> + struct platform_device *pdev;
> >> + struct device *dev = NULL;
> >> + struct device_node *np;
> >> + const char *dev_name;
> >> +
> >> + np = tegra_clk_get_of_node(hw);
> >> +
> >> + if (!of_device_is_available(np))
> >> + goto put_node;
> >> +
> >> + dev_name = kasprintf(GFP_KERNEL, "tegra_clk_%s", hw->init->name);
> >> + if (!dev_name)
> >> + goto put_node;
> >> +
> >> + pdev = of_platform_device_create(np, dev_name, NULL);
> >> + if (!pdev) {
> >> + pr_err("%s: failed to create device for %pOF\n", __func__, np);
> >> + kfree(dev_name);
> >> + goto put_node;
> >> + }
> >> +
> >> + dev = &pdev->dev;
> >> + pm_runtime_enable(dev);
> >> +put_node:
> >> + of_node_put(np);
> >> +
> >> + return clk_register(dev, hw);
> >> +}
> >
> > This looks wrong. Why do we need struct platform_device objects for each
> > of these clocks? That's going to be a massive amount of platform devices
> > and they will completely mess up sysfs.
>
> RPM works with a device. It's not a massive amount of devices, it's one
> device for T20 and four devices for T30.

I'm still not sure I understand why we need to call RPM functions on a
clock. And even if they are few, it seems wrong to make these platform
devices.

Perhaps they can be simple struct device:s instead? Ideally they would
also be parented to the CAR so that they appear in the right place in
the sysfs hierarchy.

Thierry

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