Re: [PATCH 6/9] clk: davinci: pll: allow dev == NULL

[David Lechner]

On 05/30/2018 02:46 PM, Michael Turquette wrote:
> Hi David,
>
> Quoting David Lechner (2018-05-25 11:11:47)
> > This modifies the TI Davinci PLL clock driver to allow for the case
> > when dev == NULL. On some (most) SoCs that use this driver, the PLL
> > clock needs to be registered during early boot because it is used
> > for clocksource/clkevent and there will be no platform device available.
>
> A lot of this stuff feels like a step backwards. E.g:
>
> > diff --git a/drivers/clk/davinci/pll.c b/drivers/clk/davinci/pll.c
> > index 23a24c944f1d..2eb981e61185 100644
> > --- a/drivers/clk/davinci/pll.c
> > +++ b/drivers/clk/davinci/pll.c
> > @@ -11,6 +11,7 @@
> >   
> >   #include <linux/clk-provider.h>
> >   #include <linux/clk.h>
> > +#include <linux/clk/davinci.h>
> >   #include <linux/delay.h>
> >   #include <linux/err.h>
> >   #include <linux/io.h>
> > @@ -223,6 +224,7 @@ static const struct clk_ops dm365_pll_ops = {
> >   
> >   /**
> >    * davinci_pll_div_register - common *DIV clock implementation
> > + * @dev: The PLL platform device or NULL
> >    * @name: the clock name
> >    * @parent_name: the parent clock name
> >    * @reg: the *DIV register
> > @@ -240,17 +242,21 @@ static struct clk *davinci_pll_div_register(struct device *dev,
> >          const struct clk_ops *divider_ops = &clk_divider_ops;
> >          struct clk_gate *gate;
> >          struct clk_divider *divider;
> > +       struct clk *clk;
> > +       int ret;
> >   
> > -       gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
> > +       gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> >          if (!gate)
> >                  return ERR_PTR(-ENOMEM);
> >   
> >          gate->reg = reg;
> >          gate->bit_idx = DIV_ENABLE_SHIFT;
> >   
> > -       divider = devm_kzalloc(dev, sizeof(*divider), GFP_KERNEL);
> > -       if (!divider)
> > -               return ERR_PTR(-ENOMEM);
> > +       divider = kzalloc(sizeof(*divider), GFP_KERNEL);
> > +       if (!divider) {
> > +               ret = -ENOMEM;
> > +               goto err_free_gate;
> > +       }
> >   
> >          divider->reg = reg;
> >          divider->shift = DIV_RATIO_SHIFT;
>
> Oh no my poor devm_ helpers!
>
> I understand that we need to support early boot drivers better, so this
> patch can be merged.
>
> However I'm curious if you're tracking Bartosz's early_platform_driver
> efforts? Converting to that if it is ever merged would likely be
> cleaner:
>
> https://lkml.kernel.org/r/20180511162028.20616-1-brgl@xxxxxxxx
>
> Best regards,
> Mike

Yes. In fact, this is what got Bartosz working on it in the first
place. :-)