Re: [PATCH V3 3/7] clk: imx: fracn-gppll: support integer pll

From: Abel Vesa
Date: Sun Apr 09 2023 - 09:45:44 EST

On 23-04-03 17:52:56, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
>
> The fracn gppll could be configured in FRAC or INTEGER mode during
> hardware design. The current driver only support FRAC mode, while
> this patch introduces INTEGER support. When the PLL is INTEGER pll,
> there is no mfn, mfd, the calculation is as below:
> Fvco_clk = (Fref / DIV[RDIV] ) * DIV[MFI]
> Fclko_odiv = Fvco_clk / DIV[ODIV]
>
> In this patch, we reuse the FRAC pll logic with some condition check to
> simplify the driver
>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---

Reviewed-by: Abel Vesa <abel.vesa@xxxxxxxxxx>

> drivers/clk/imx/clk-fracn-gppll.c | 68 +++++++++++++++++++++++++++----
> drivers/clk/imx/clk.h | 7 ++++
> 2 files changed, 68 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/clk/imx/clk-fracn-gppll.c b/drivers/clk/imx/clk-fracn-gppll.c
> index f6674110a88e..e2633ad94640 100644
> --- a/drivers/clk/imx/clk-fracn-gppll.c
> +++ b/drivers/clk/imx/clk-fracn-gppll.c
> @@ -53,11 +53,22 @@
> .odiv = (_odiv), \
> }
>
> +#define PLL_FRACN_GP_INTEGER(_rate, _mfi, _rdiv, _odiv) \
> + { \
> + .rate = (_rate), \
> + .mfi = (_mfi), \
> + .mfn = 0, \
> + .mfd = 0, \
> + .rdiv = (_rdiv), \
> + .odiv = (_odiv), \
> + }
> +
> struct clk_fracn_gppll {
> struct clk_hw hw;
> void __iomem *base;
> const struct imx_fracn_gppll_rate_table *rate_table;
> int rate_count;
> + u32 flags;
> };
>
> /*
> @@ -83,6 +94,24 @@ struct imx_fracn_gppll_clk imx_fracn_gppll = {
> };
> EXPORT_SYMBOL_GPL(imx_fracn_gppll);
>
> +/*
> + * Fvco = (Fref / rdiv) * MFI
> + * Fout = Fvco / odiv
> + * The (Fref / rdiv) should be in range 20MHz to 40MHz
> + * The Fvco should be in range 2.5Ghz to 5Ghz
> + */
> +static const struct imx_fracn_gppll_rate_table int_tbl[] = {
> + PLL_FRACN_GP_INTEGER(1700000000U, 141, 1, 2),
> + PLL_FRACN_GP_INTEGER(1400000000U, 175, 1, 3),
> + PLL_FRACN_GP_INTEGER(900000000U, 150, 1, 4),
> +};
> +
> +struct imx_fracn_gppll_clk imx_fracn_gppll_integer = {
> + .rate_table = int_tbl,
> + .rate_count = ARRAY_SIZE(int_tbl),
> +};
> +EXPORT_SYMBOL_GPL(imx_fracn_gppll_integer);
> +
> static inline struct clk_fracn_gppll *to_clk_fracn_gppll(struct clk_hw *hw)
> {
> return container_of(hw, struct clk_fracn_gppll, hw);
> @@ -169,9 +198,15 @@ static unsigned long clk_fracn_gppll_recalc_rate(struct clk_hw *hw, unsigned lon
> break;
> }
>
> - /* Fvco = Fref * (MFI + MFN / MFD) */
> - fvco = fvco * mfi * mfd + fvco * mfn;
> - do_div(fvco, mfd * rdiv * odiv);
> + if (pll->flags & CLK_FRACN_GPPLL_INTEGER) {
> + /* Fvco = (Fref / rdiv) * MFI */
> + fvco = fvco * mfi;
> + do_div(fvco, rdiv * odiv);
> + } else {
> + /* Fvco = (Fref / rdiv) * (MFI + MFN / MFD) */
> + fvco = fvco * mfi * mfd + fvco * mfn;
> + do_div(fvco, mfd * rdiv * odiv);
> + }
>
> return (unsigned long)fvco;
> }
> @@ -215,8 +250,10 @@ static int clk_fracn_gppll_set_rate(struct clk_hw *hw, unsigned long drate,
> pll_div = FIELD_PREP(PLL_RDIV_MASK, rate->rdiv) | rate->odiv |
> FIELD_PREP(PLL_MFI_MASK, rate->mfi);
> writel_relaxed(pll_div, pll->base + PLL_DIV);
> - writel_relaxed(rate->mfd, pll->base + PLL_DENOMINATOR);
> - writel_relaxed(FIELD_PREP(PLL_MFN_MASK, rate->mfn), pll->base + PLL_NUMERATOR);
> + if (pll->flags & CLK_FRACN_GPPLL_FRACN) {
> + writel_relaxed(rate->mfd, pll->base + PLL_DENOMINATOR);
> + writel_relaxed(FIELD_PREP(PLL_MFN_MASK, rate->mfn), pll->base + PLL_NUMERATOR);
> + }
>
> /* Wait for 5us according to fracn mode pll doc */
> udelay(5);
> @@ -300,8 +337,10 @@ static const struct clk_ops clk_fracn_gppll_ops = {
> .set_rate = clk_fracn_gppll_set_rate,
> };
>
> -struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, void __iomem *base,
> - const struct imx_fracn_gppll_clk *pll_clk)
> +static struct clk_hw *_imx_clk_fracn_gppll(const char *name, const char *parent_name,
> + void __iomem *base,
> + const struct imx_fracn_gppll_clk *pll_clk,
> + u32 pll_flags)
> {
> struct clk_fracn_gppll *pll;
> struct clk_hw *hw;
> @@ -322,6 +361,7 @@ struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, vo
> pll->hw.init = &init;
> pll->rate_table = pll_clk->rate_table;
> pll->rate_count = pll_clk->rate_count;
> + pll->flags = pll_flags;
>
> hw = &pll->hw;
>
> @@ -334,4 +374,18 @@ struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, vo
>
> return hw;
> }
> +
> +struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, void __iomem *base,
> + const struct imx_fracn_gppll_clk *pll_clk)
> +{
> + return _imx_clk_fracn_gppll(name, parent_name, base, pll_clk, CLK_FRACN_GPPLL_FRACN);
> +}
> EXPORT_SYMBOL_GPL(imx_clk_fracn_gppll);
> +
> +struct clk_hw *imx_clk_fracn_gppll_integer(const char *name, const char *parent_name,
> + void __iomem *base,
> + const struct imx_fracn_gppll_clk *pll_clk)
> +{
> + return _imx_clk_fracn_gppll(name, parent_name, base, pll_clk, CLK_FRACN_GPPLL_INTEGER);
> +}
> +EXPORT_SYMBOL_GPL(imx_clk_fracn_gppll_integer);
> diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
> index 055bc9197fb4..cb4e4c4b8278 100644
> --- a/drivers/clk/imx/clk.h
> +++ b/drivers/clk/imx/clk.h
> @@ -73,6 +73,9 @@ extern struct imx_pll14xx_clk imx_1416x_pll;
> extern struct imx_pll14xx_clk imx_1443x_pll;
> extern struct imx_pll14xx_clk imx_1443x_dram_pll;
>
> +#define CLK_FRACN_GPPLL_INTEGER BIT(0)
> +#define CLK_FRACN_GPPLL_FRACN BIT(1)
> +
> /* NOTE: Rate table should be kept sorted in descending order. */
> struct imx_fracn_gppll_rate_table {
> unsigned int rate;
> @@ -91,8 +94,12 @@ struct imx_fracn_gppll_clk {
>
> struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, void __iomem *base,
> const struct imx_fracn_gppll_clk *pll_clk);
> +struct clk_hw *imx_clk_fracn_gppll_integer(const char *name, const char *parent_name,
> + void __iomem *base,
> + const struct imx_fracn_gppll_clk *pll_clk);
>
> extern struct imx_fracn_gppll_clk imx_fracn_gppll;
> +extern struct imx_fracn_gppll_clk imx_fracn_gppll_integer;
>
> #define imx_clk_cpu(name, parent_name, div, mux, pll, step) \
> to_clk(imx_clk_hw_cpu(name, parent_name, div, mux, pll, step))
> --
> 2.37.1
>