Hi Stephen,
On Thu, 1 Oct 2015 15:32:20 -0700
Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote:
> On 09/22, Jisheng Zhang wrote:
> > diff --git a/drivers/clk/berlin/pll.c b/drivers/clk/berlin/pll.c
> > new file mode 100644
> > index 0000000..9aad0b6
> > --- /dev/null
> > +++ b/drivers/clk/berlin/pll.c
> > @@ -0,0 +1,119 @@
> > +
> > +#define to_berlin_pll(hw) container_of(hw, struct berlin_pll, hw)
> > +
> > +static u8 vcodiv_berlin[] = {1, 2, 4, 8, 16, 32, 64, 128};
>
> This is an array of 1 << index position...
oops, yes! I didn't realize this before! Accept all the comments below, will
update in v2.
Thanks a lot for review,
Jisheng
>
> > +
> > +static unsigned long berlin_pll_recalc_rate(struct clk_hw *hw,
> > + unsigned long parent_rate)
> > +{
> > + u32 val, fbdiv, rfdiv, vcodivsel, bypass;
> > + struct berlin_pll *pll = to_berlin_pll(hw);
> > +
> > + bypass = readl_relaxed(pll->bypass);
> > + if (bypass & (1 << pll->bypass_shift))
> > + return parent_rate;
> > +
> > + val = readl_relaxed(pll->ctrl + PLL_CTRL0);
> > + fbdiv = (val >> 12) & 0x1FF;
> > + rfdiv = (val >> 3) & 0x1FF;
> > + val = readl_relaxed(pll->ctrl + PLL_CTRL1);
> > + vcodivsel = (val >> 9) & 0x7;
> > + return parent_rate * fbdiv * 4 / rfdiv /
> > + vcodiv_berlin[vcodivsel];
>
> so we can replace this with 1 << vcodivsel?
>
> > +}
> > +
> > +static u8 berlin_pll_get_parent(struct clk_hw *hw)
> > +{
> > + struct berlin_pll *pll = to_berlin_pll(hw);
> > + u32 bypass = readl_relaxed(pll->bypass);
> > +
> > + if (bypass & (1 << pll->bypass_shift))
> > + return 1;
> > + else
> > + return 0;
>
> Simplify this to
>
> if (bypass & (1 << pll->bypass_shift))
> return 1;
> return 0;
>
> or
>
> return !!(bypass & (1 << pll->bypass_shift))
>
> > +}
> > +
> > +static const struct clk_ops berlin_pll_ops = {
> > + .recalc_rate = berlin_pll_recalc_rate,
> > + .get_parent = berlin_pll_get_parent,
> > +};
> > +
> > +void __init berlin_pll_setup(struct device_node *np)
>
> static?
>
> > +{
> > + struct clk_init_data init;
> > + struct berlin_pll *pll;
> > + const char *parent_names[PLL_SOURCE_MAX];
> > + struct clk *clk;
> > + int ret, num_parents;
> > +
> > + num_parents = of_clk_get_parent_count(np);
> > + if (num_parents <= 0 || num_parents > PLL_SOURCE_MAX)
> > + return;
> > +
> > + of_clk_parent_fill(np, parent_names, num_parents);
> > +
> > + pll = kzalloc(sizeof(*pll), GFP_KERNEL);
> > + if (WARN_ON(!pll))
>
> We already print a big warning on allocation failures, so drop
> the WARN_ON please.
>
> > + return;
> > +
> > + pll->ctrl = of_iomap(np, 0);
> > + pll->bypass = of_iomap(np, 1);
> > + ret = of_property_read_u8(np, "bypass-shift", &pll->bypass_shift);
> > + if (WARN_ON(!pll->ctrl || !pll->bypass || ret))
> > + return;
> > +
> > + init.name = np->name;
> > + init.ops = &berlin_pll_ops;
> > + init.parent_names = parent_names;
> > + init.num_parents = num_parents;
>
> init.flags is not initialized. Please initialize the init struct
> on the stack to 0 to avoid future problems.
>
> > +
> > + pll->hw.init = &init;
> > +
> > + clk = clk_register(NULL, &pll->hw);
> > + if (WARN_ON(IS_ERR(clk)))
> > + return;
> > +
> > + ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> > + if (WARN_ON(ret))
> > + return;
>
> This return is useless.
>
> > +}
>
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