Re: [PATCH v1 02/11] clk: mediatek: add new member to mtk_pll_data

Weiyi Lu
2018-11-20T03:51:29Z

On Tue, 2018-11-13 at 08:18 -0800, Nicolas Boichat wrote:
> On Mon, Nov 5, 2018 at 10:43 PM Weiyi Lu <weiyi.lu@mediatek.com> wrote:
> >
> > From: Owen Chen <owen.chen@mediatek.com>
> >
> > 1. pcwibits: The integer bits of pcw for plls is extend to 8 bits,
> > add a variable to indicate this change and
> > backward-compatible.
> > 2. fmin: The pll freqency lower-bound is vary from 1GMhz to
> > 1.5Ghz, add a variable to indicate platform-dependent.
> >
> > Signed-off-by: Owen Chen <owen.chen@mediatek.com>
> > ---
> > drivers/clk/mediatek/clk-mtk.h | 2 ++
> > drivers/clk/mediatek/clk-pll.c | 10 +++++++---
> > 2 files changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
> > index f83c2bbb677e..1882221fe994 100644
> > --- a/drivers/clk/mediatek/clk-mtk.h
> > +++ b/drivers/clk/mediatek/clk-mtk.h
> > @@ -215,7 +215,9 @@ struct mtk_pll_data {
> > const struct clk_ops *ops;
> > u32 rst_bar_mask;
> > unsigned long fmax;
> > + unsigned long fmin;
>
> Minor nit: I'd put fmin before fmax in the structure.
>

OK, thanks for the suggestion. will fix in next version

> > int pcwbits;
> > + int pcwibits;
> > uint32_t pcw_reg;
> > int pcw_shift;
> > const struct mtk_pll_div_table *div_table;
> > diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
> > index f54e4015b0b1..0ec2c62d9383 100644
> > --- a/drivers/clk/mediatek/clk-pll.c
> > +++ b/drivers/clk/mediatek/clk-pll.c
>
> I'd add a note next to:
> #define INTEGER_BITS 7
> to say that this is the default, and can be overridden with pcwibits.
>

OK, thanks for the suggestion. will add in next version

> > @@ -69,11 +69,13 @@ static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
> > {
> > int pcwbits = pll->data->pcwbits;
> > int pcwfbits;
> > + int ibits;
> > u64 vco;
> > u8 c = 0;
> >
> > /* The fractional part of the PLL divider. */
> > - pcwfbits = pcwbits > INTEGER_BITS ? pcwbits - INTEGER_BITS : 0;
> > + ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
> > + pcwfbits = pcwbits > ibits ? pcwbits - ibits : 0;
> >
> > vco = (u64)fin * pcw;
> >
> > @@ -138,9 +140,10 @@ static void mtk_pll_set_rate_regs(struct mtk_clk_pll *pll, u32 pcw,
> > static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
> > u32 freq, u32 fin)
> > {
> > - unsigned long fmin = 1000 * MHZ;
> > + unsigned long fmin = pll->data->fmin ? pll->data->fmin : 1000 * MHZ;
>
> I'd put parentheses around (1000 * MHZ), to avoid the need to think
> about precedence...
>

OK, thanks for the suggestion. will add in next version

> > const struct mtk_pll_div_table *div_table = pll->data->div_table;
> > u64 _pcw;
> > + int ibits;
> > u32 val;
> >
> > if (freq > pll->data->fmax)
> > @@ -164,7 +167,8 @@ static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
> > }
> >
> > /* _pcw = freq * postdiv / fin * 2^pcwfbits */
> > - _pcw = ((u64)freq << val) << (pll->data->pcwbits - INTEGER_BITS);
> > + ibits = pll->data->pcwibits ? pll->data->pcwibits : INTEGER_BITS;
> > + _pcw = ((u64)freq << val) << (pll->data->pcwbits - ibits);
> > do_div(_pcw, fin);
> >
> > *pcw = (u32)_pcw;
> > --
> > 2.18.0
> >
>
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