linux-kernel - Re: [PATCH v5 3/9] clk: mediatek: Add configurable pcwibits and fmin to mtk_pll

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Message-ID: <CANMq1KDciN76ZRL7kLPWM--3sHNi3bbjV86Sixm4R=QUKwrx1A@mail.gmail.com>
Date:   Fri, 8 Mar 2019 14:20:27 +0800
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     Weiyi Lu <weiyi.lu@...iatek.com>
Cc:     Matthias Brugger <matthias.bgg@...il.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Rob Herring <robh@...nel.org>,
        James Liao <jamesjj.liao@...iatek.com>,
        Fan Chen <fan.chen@...iatek.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>, linux-clk@...r.kernel.org,
        srv_heupstream <srv_heupstream@...iatek.com>,
        stable@...r.kernel.org, Owen Chen <owen.chen@...iatek.com>
Subject: Re: [PATCH v5 3/9] clk: mediatek: Add configurable pcwibits and fmin
 to mtk_pll_data

On Tue, Mar 5, 2019 at 1:06 PM Weiyi Lu <weiyi.lu@...iatek.com> wrote:
>
> From: Owen Chen <owen.chen@...iatek.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

Minor nit: frequency (Stephen I guess you could fix that when applying...)

>    1.5Ghz, add a variable to indicate platform-dependent.
>
> Signed-off-by: Owen Chen <owen.chen@...iatek.com>
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> Acked-by: Sean Wang <sean.wang@...nel.org>

Reviewed-and-tested-by: Nicolas Boichat <drinkcat@...omium.org>

> ---
>  drivers/clk/mediatek/clk-mtk.h |  2 ++
>  drivers/clk/mediatek/clk-pll.c | 15 +++++++++++----
>  2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
> index f83c2bbb677e..11b5517903d0 100644
> --- a/drivers/clk/mediatek/clk-mtk.h
> +++ b/drivers/clk/mediatek/clk-mtk.h
> @@ -214,8 +214,10 @@ struct mtk_pll_data {
>         unsigned int flags;
>         const struct clk_ops *ops;
>         u32 rst_bar_mask;
> +       unsigned long fmin;
>         unsigned long fmax;
>         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 18842d660317..67aaa3082d9b 100644
> --- a/drivers/clk/mediatek/clk-pll.c
> +++ b/drivers/clk/mediatek/clk-pll.c
> @@ -32,6 +32,8 @@
>  #define AUDPLL_TUNER_EN                BIT(31)
>
>  #define POSTDIV_MASK           0x7
> +
> +/* default 7 bits integer, can be overridden with pcwibits. */
>  #define INTEGER_BITS           7
>
>  /*
> @@ -68,12 +70,15 @@ static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
>                 u32 pcw, int postdiv)
>  {
>         int pcwbits = pll->data->pcwbits;
> -       int pcwfbits;
> +       int pcwfbits = 0;
> +       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;
> +       if (pcwbits > ibits)
> +               pcwfbits = pcwbits - ibits;
>
>         vco = (u64)fin * pcw;
>
> @@ -170,9 +175,10 @@ 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);
>         const struct mtk_pll_div_table *div_table = pll->data->div_table;
>         u64 _pcw;
> +       int ibits;
>         u32 val;
>
>         if (freq > pll->data->fmax)
> @@ -196,7 +202,8 @@ 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
>