Hi Stephen,
thanks for respond, my comments are inlined below.
On Thu, 2017-08-03 at 18:53 -0700, Stephen Boyd wrote:
> On 07/14, Eugeniy Paltsev wrote:
> [...]
> > + dev_dbg(clk->dev, "write configurarion: 0x%x", val);
>
> Or just use %#x to add the 0x part.
Thanks, I don't know about this option.
>
> [...]
>
> > + /* input divider = reg.idiv + 1 */
> > + idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >>
> > CGU_PLL_CTRL_IDIV_SHIFT);
> > + /* fb divider = 2*(reg.fbdiv + 1) */
> > + fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >>
> > CGU_PLL_CTRL_FBDIV_SHIFT));
> > + /* output divider = 2^(reg.odiv) */
> > + odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >>
> > CGU_PLL_CTRL_ODIV_SHIFT);
>
> Maybe just drop these comments. They're just repeating the code.
Actually I would prefer to keep them, as "2^(reg.odiv)" is more
human-readable then
"1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT)"
> > +
> > + rate = (u64)parent_rate * fbdiv;
> > + do_div(rate, idiv * odiv);
> > +
> > + return rate;
> > +}
> > +
> > +static long hsdk_pll_round_rate(struct clk_hw *hw, unsigned long
> > rate,
> > + unsigned long *prate)
> > +{
> > + int i;
> > + long best_rate;
> > + struct hsdk_pll_clk *clk = to_hsdk_pll_clk(hw);
> > + const struct hsdk_pll_cfg *pll_cfg = clk->pll_cfg;
> > +
> > + if (pll_cfg[0].rate == 0)
> > + return -EINVAL;
>
> This happens?
Only if we add bad hsdk_pll_cfg table. But it is quite cold code - we
change pll configuration quite rare, so maybe it's better to keep this
assert?
> > +
> > + best_rate = pll_cfg[0].rate;
> > +
> > + for (i = 1; pll_cfg[i].rate != 0; i++) {
> > + if (abs(rate - pll_cfg[i].rate) < abs(rate -
> > best_rate))
>
> Alright, rate is unsigned long, and best_rate is long. abs() does
> the right thing here, but it makes me have to think twice if
> best_rate can be negative and then this is a larger number, not a
> smaller one. Can we make best_rate unsigned long in this
> function?
Yes, we can.
Anyway it's a bit strange what rate is unsigned long and round_rate
return value is long.
--
Eugeniy Paltsev
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