>> diff --git a/drivers/clk/imx/clk-pllv3.c b/drivers/clk/imx/clk-pllv3.c
>> index 19f9b622981a..24a9e914e0d5 100644
>> --- a/drivers/clk/imx/clk-pllv3.c
>> +++ b/drivers/clk/imx/clk-pllv3.c
>> @@ -288,6 +291,87 @@ static const struct clk_ops clk_pllv3_av_ops = {
>> .set_rate = clk_pllv3_av_set_rate,
>> };
>>
>> +static unsigned long clk_pllv3_vf610_recalc_rate(struct clk_hw *hw,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_pllv3 *pll = to_clk_pllv3(hw);
>> + u32 mfn = readl_relaxed(pll->base + PLL_VF610_NUM_OFFSET);
>> + u32 mfd = readl_relaxed(pll->base + PLL_VF610_DENOM_OFFSET);
>> + u32 div = (readl_relaxed(pll->base) & pll->div_mask) ? 22 : 20;
>> + u64 temp64 = (u64)parent_rate;
>
> Useless cast, please remove.
Ok
>> +
>> + temp64 *= mfn;
>> + do_div(temp64, mfd);
>> +
>> + return (parent_rate * div) + (u32)temp64;
>> +}
>> +
>> +static long clk_pllv3_vf610_round_rate(struct clk_hw *hw, unsigned long
>> rate,
>> + unsigned long *prate)
>> +{
>> + unsigned long parent_rate = *prate;
>> + unsigned int mfi = (rate >= 22 * parent_rate) ? 22 : 20;
>
> What is the importance of 22 and 20? Hint, at the least it needs
> a comment.
These come directly from datasheet:
Frequency multipler selection (MFI).
0: Fout = Fref * 20
1: Fout = Fref * 22
These numbers (20 / 22) are common among flavours of pllv3 hardware.
In similar places in the same file (e.g. in clk_pllv3_recalc_rate(), in
clk_pllv3_set_rate() ,etc) there are no comments explaining them.
Are you sure this place is special and comment is needed here?
>> + u32 mfn, mfd = 0x3fffffff;
>> + u64 temp64;
>> +
>> + if (rate <= parent_rate * mfi)
>> + mfn = 0;
>> + else if (rate >= parent_rate * (mfi + 1))
>> + mfn = mfd - 1;
>> + else {
>> + /* rate = parent_rate * (mfi + mfn/mfd) */
>> + temp64 = rate - parent_rate * mfi;
>> + temp64 *= mfd;
>> + do_div(temp64, parent_rate);
>> + mfn = temp64;
>> + }
>> +
>> + temp64 = ((u64)mfd * mfi + mfn) * parent_rate;
>> + do_div(temp64, mfd);
>> + return (u32)temp64;
>
> Do we need the cast here for some reason?
Just for readability, can remove if it hurts.
>> +}
>> +
>> +static int clk_pllv3_vf610_set_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_pllv3 *pll = to_clk_pllv3(hw);
>> + unsigned int mfi = (rate >= 22 * parent_rate) ? 22 : 20;
>> + u32 val, mfn, mfd = 0x3fffffff;
>> + u64 temp64;
>> +
>> + if (rate <= parent_rate * mfi)
>> + mfn = 0;
>> + else if (rate >= parent_rate * (mfi + 1))
>> + mfn = mfd - 1;
>> + else {
>> + /* rate = parent_rate * (mfi + mfn/mfd) */
>> + temp64 = rate - parent_rate * mfi;
>> + temp64 *= mfd;
>> + do_div(temp64, parent_rate);
>> + mfn = temp64;
>> + }
>> +
>> + val = readl_relaxed(pll->base);
>> + if (mfi == 20)
>
> Presumably this is another place 20 and 22 are special.
See my reply above. Same applies here.
Nikita
