linux-kernel - Re: [PATCH v2 4/5] clk: mediatek: Add configurable enable control to mtk_pll

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Message-ID: <CANMq1KCG1xUan5-=DBZewvTqmUH=p7=nxy0Va=pdYBhAfYhhjQ@mail.gmail.com>
Date:   Wed, 29 Jul 2020 18:58:06 +0800
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     Weiyi Lu <weiyi.lu@...iatek.com>
Cc:     Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh@...nel.org>, Stephen Boyd <sboyd@...nel.org>,
        James Liao <jamesjj.liao@...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>,
        Wendell Lin <wendell.lin@...iatek.com>
Subject: Re: [PATCH v2 4/5] clk: mediatek: Add configurable enable control to mtk_pll_data

On Wed, Jul 29, 2020 at 4:44 PM Weiyi Lu <weiyi.lu@...iatek.com> wrote:
>
> In all MediaTek PLL design, bit0 of CON0 register is always
> the enable bit.
> However, there's a special case of usbpll on MT8192.
> The enable bit of usbpll is moved to bit2 of other register.
> Add configurable en_reg and pll_en_bit for enable control or
> default 0 where pll data are static variables.
> Hence, CON0_BASE_EN could also be removed.
> And there might have another special case on other chips,
> the enable bit is still on CON0 register but not at bit0.
>
> Signed-off-by: Weiyi Lu <weiyi.lu@...iatek.com>
> ---
>  drivers/clk/mediatek/clk-mtk.h |  2 ++
>  drivers/clk/mediatek/clk-pll.c | 18 +++++++++++-------
>  2 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/clk/mediatek/clk-mtk.h b/drivers/clk/mediatek/clk-mtk.h
> index c3d6756..810eb97 100644
> --- a/drivers/clk/mediatek/clk-mtk.h
> +++ b/drivers/clk/mediatek/clk-mtk.h
> @@ -233,6 +233,8 @@ struct mtk_pll_data {
>         uint32_t pcw_chg_reg;
>         const struct mtk_pll_div_table *div_table;
>         const char *parent_name;
> +       uint32_t en_reg;
> +       uint8_t pll_en_bit;
>  };
>
>  void mtk_clk_register_plls(struct device_node *node,
> diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
> index 3c79e1a..1434e99 100644
> --- a/drivers/clk/mediatek/clk-pll.c
> +++ b/drivers/clk/mediatek/clk-pll.c
> @@ -16,7 +16,6 @@
>  #define REG_CON0               0
>  #define REG_CON1               4
>
> -#define CON0_BASE_EN           BIT(0)
>  #define CON0_PWR_ON            BIT(0)
>  #define CON0_ISO_EN            BIT(1)
>  #define PCW_CHG_MASK           BIT(31)
> @@ -44,6 +43,7 @@ struct mtk_clk_pll {
>         void __iomem    *tuner_en_addr;
>         void __iomem    *pcw_addr;
>         void __iomem    *pcw_chg_addr;
> +       void __iomem    *en_addr;
>         const struct mtk_pll_data *data;
>  };
>
> @@ -56,7 +56,7 @@ static int mtk_pll_is_prepared(struct clk_hw *hw)
>  {
>         struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
>
> -       return (readl(pll->base_addr + REG_CON0) & CON0_BASE_EN) != 0;
> +       return (readl(pll->en_addr) & BIT(pll->data->pll_en_bit)) != 0;
>  }
>
>  static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
> @@ -247,8 +247,8 @@ static int mtk_pll_prepare(struct clk_hw *hw)
>         writel(r, pll->pwr_addr);
>         udelay(1);
>
> -       r = readl(pll->base_addr + REG_CON0) | CON0_BASE_EN;
> -       writel(r, pll->base_addr + REG_CON0);
> +       r = readl(pll->en_addr) | BIT(pll->data->pll_en_bit);
> +       writel(r, pll->en_addr);
>
>         r = readl(pll->base_addr + REG_CON0) | pll->data->en_mask;
>         writel(r, pll->base_addr + REG_CON0);
> @@ -283,9 +283,9 @@ static void mtk_pll_unprepare(struct clk_hw *hw)
>         r &= ~pll->data->en_mask;
>         writel(r, pll->base_addr + REG_CON0);
>
> -       r = readl(pll->base_addr + REG_CON0);
> -       r &= ~CON0_BASE_EN;
> -       writel(r, pll->base_addr + REG_CON0);
> +       r = readl(pll->en_addr);
> +       r &= ~BIT(pll->data->pll_en_bit);

1 line, but that'll come naturally from the change I requested in the
previous patch.

> +       writel(r, pll->en_addr);
>
>         r = readl(pll->pwr_addr) | CON0_ISO_EN;
>         writel(r, pll->pwr_addr);
> @@ -327,6 +327,10 @@ static struct clk *mtk_clk_register_pll(const struct mtk_pll_data *data,
>                 pll->tuner_addr = base + data->tuner_reg;
>         if (data->tuner_en_reg)
>                 pll->tuner_en_addr = base + data->tuner_en_reg;
> +       if (data->en_reg)
> +               pll->en_addr = base + data->en_reg;
> +       else
> +               pll->en_addr = pll->base_addr + REG_CON0;

Don't you need to set pll->data->pll_en_bit to CON0_BASE_EN here?
(which probably means that you need to add a pll->en_bit field to
struct mtk_clk_pll)

>         pll->hw.init = &init;
>         pll->data = data;
>
> --
> 1.8.1.1.dirty