Re: [PATCH v10 2/4] clk: clk-loongson2: add clock controller driver support

[zhuyinbo]

在 2023/2/18 上午6:15, Stephen Boyd 写道:
> Quoting zhuyinbo (2023-02-14 23:35:22)
> > 在 2023/2/11 上午7:42, Stephen Boyd 写道:
> > > Quoting Yinbo Zhu (2022-11-28 19:41:55)
> > >
> > > > +
> > > > +       mult = (val >> LOONGSON2_USB_FREQSCALE_SHIFT) &
> > > > +                       clk_div_mask(LOONGSON2_USB_FREQSCALE_WIDTH);
> > > > +
> > > > +       rate = parent_rate * (mult + 1);
> > > > +       do_div(rate, 8);
> > > Why is do_div() being used?
> > no expecial reason, I only want to get a result that rate divide 8.
> Ok, you can use div_u64() here and simplify.
okay, I got it.
> > you meaning is to use clk_parent_data to rework
> > loongson2_clk_pll_register  and drop
> >
> > loongson2_obtain_fixed_clk_hw ?
> Yes
>
> > > > +}
> > > > +
> > > > +static void __init loongson2_clocks_init(struct device_node *np)
> > > > +{
> > > > +       struct clk_hw **hws;
> > > > +       struct clk_hw_onecell_data *clk_hw_data;
> > > > +       spinlock_t loongson2_clk_lock;
> > > > +
> > > > +       loongson2_pll_base = of_iomap(np, 0);
> > > > +
> > > > +       if (!loongson2_pll_base) {
> > > > +               pr_err("clk: unable to map loongson2 clk registers\n");
> > > > +               goto err;
> > > return?
> > sorry, I don't get it.  you meaning is that  remove "goto err". Instead,
> > add a "return".
> Yes.
>
> > > > +       }
> > > > +
> > > > +       clk_hw_data = kzalloc(struct_size(clk_hw_data, hws, LOONGSON2_CLK_END),
> > > > +                                       GFP_KERNEL);
> > > > +       if (WARN_ON(!clk_hw_data))
> > > > +               goto err;
> [...]
> > > > +
> > > > +err:
> > > > +       iounmap(loongson2_pll_base);
> > > > +}
> > > > +
> > > > +CLK_OF_DECLARE(loongson2_clk, "loongson,ls2k-clk", loongson2_clocks_init);
> > > Any reason this can't be a platform driver?

Your question is that  why I don't use the platform_driver_register to 
register  clk and use CLK_OF_DECLARE ?

I was  consider other clock controllers of Loongson-2 series may be 
different with 2k1000 and I can add a line

CLK_OF_DECLARE() for compatible other platform in the future. eg.

CLK_OF_DECLARE(loongson2_clk, "loongson,ls2k-clk", loongson2_clocks_init);

+  CLK_OF_DECLARE(xxx1, xxx2,  xxx3);  // for other clock controllers of 
Loongson-2 series

> > For the compatible consideration of other clock controllers of
> > Loongson-2 series in the future, the way of using dts can be
> >
> > better compatible.
> Sorry that sentence doesn't make sense to me. The use of dts doesn't
> require the use of CLK_OF_DECLARE.

yes, the use of dts doesn't require the use of CLK_OF_DECLARE and can 
use platform_driver_register

but my drvier not use platform_driver_register to register  clk and use 
CLK_OF_DECLARE to match of_clk_init.