linux-kernel - RE: [PATCH v2 3/4] clk: samsung: clk-pll: Add support for pll

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Message-ID: <000601dad12e$19ff3f30$4dfdbd90$@samsung.com>
Date: Mon, 8 Jul 2024 17:28:06 +0530
From: "Alim Akhtar" <alim.akhtar@...sung.com>
To: "'Sunyeal Hong'" <sunyeal.hong@...sung.com>, "'Krzysztof Kozlowski'"
	<krzk@...nel.org>, "'Sylwester Nawrocki'" <s.nawrocki@...sung.com>,
	"'Chanwoo Choi'" <cw00.choi@...sung.com>, "'Michael Turquette'"
	<mturquette@...libre.com>, "'Stephen Boyd'" <sboyd@...nel.org>, "'Rob
 Herring'" <robh@...nel.org>, "'Conor Dooley'" <conor+dt@...nel.org>
Cc: <linux-samsung-soc@...r.kernel.org>, <linux-clk@...r.kernel.org>,
	<devicetree@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v2 3/4] clk: samsung: clk-pll: Add support for pll_531x

Hello Sunyeal,

> -----Original Message-----
> From: Sunyeal Hong <sunyeal.hong@...sung.com>
> Sent: Monday, July 8, 2024 4:44 AM
> To: Krzysztof Kozlowski <krzk@...nel.org>; Sylwester Nawrocki
> <s.nawrocki@...sung.com>; Chanwoo Choi <cw00.choi@...sung.com>;
> Alim Akhtar <alim.akhtar@...sung.com>; Michael Turquette
> <mturquette@...libre.com>; Stephen Boyd <sboyd@...nel.org>; Rob
> Herring <robh@...nel.org>; Conor Dooley <conor+dt@...nel.org>
> Cc: linux-samsung-soc@...r.kernel.org; linux-clk@...r.kernel.org;
> devicetree@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-
> kernel@...r.kernel.org; Sunyeal Hong <sunyeal.hong@...sung.com>
> Subject: [PATCH v2 3/4] clk: samsung: clk-pll: Add support for pll_531x
> 
> pll531x PLL is used in Exynos Auto v920 SoC for shared pll.
> pll531x: Integer/fractional PLL with mid frequency FVCO (800 to 3120 MHz)
> 
> PLL531x
> FOUT = (MDIV + F/2^32-F[31]) * FIN/(PDIV x 2^SDIV)
> 
Any reason for not mentioning equation for integer PLL? 

> Signed-off-by: Sunyeal Hong <sunyeal.hong@...sung.com>
> ---
Anyway, LGTM,

Reviewed-by: Alim Akhtar <alim.akhtar@...sung.com>

>  drivers/clk/samsung/clk-pll.c | 45
> +++++++++++++++++++++++++++++++++++
>  drivers/clk/samsung/clk-pll.h |  1 +
>  2 files changed, 46 insertions(+)
> 
> diff --git a/drivers/clk/samsung/clk-pll.c b/drivers/clk/samsung/clk-pll.c index
> 4be879ab917e..b3bcef074ab7 100644
> --- a/drivers/clk/samsung/clk-pll.c
> +++ b/drivers/clk/samsung/clk-pll.c
> @@ -1261,6 +1261,48 @@ static const struct clk_ops
> samsung_pll2650xx_clk_min_ops = {
>  	.recalc_rate = samsung_pll2650xx_recalc_rate,  };
> 
> +/*
> + * PLL531X Clock Type
> + */
> +/* Maximum lock time can be 500 * PDIV cycles */
> +#define PLL531X_LOCK_FACTOR		(500)
> +#define PLL531X_MDIV_MASK		(0x3FF)
> +#define PLL531X_PDIV_MASK		(0x3F)
> +#define PLL531X_SDIV_MASK		(0x7)
> +#define PLL531X_FDIV_MASK		(0xFFFF)
> +#define PLL531X_MDIV_SHIFT		(16)
> +#define PLL531X_PDIV_SHIFT		(8)
> +#define PLL531X_SDIV_SHIFT		(0)
> +
> +static unsigned long samsung_pll531x_recalc_rate(struct clk_hw *hw,
> +						 unsigned long parent_rate)
> +{
> +	struct samsung_clk_pll *pll = to_clk_pll(hw);
> +	u32 mdiv, pdiv, sdiv, pll_con0, pll_con8;
> +	s32 fdiv;
> +	u64 fout = parent_rate;
> +
> +	pll_con0 = readl_relaxed(pll->con_reg);
> +	pll_con8 = readl_relaxed(pll->con_reg + 20);
> +	mdiv = (pll_con0 >> PLL531X_MDIV_SHIFT) & PLL531X_MDIV_MASK;
> +	pdiv = (pll_con0 >> PLL531X_PDIV_SHIFT) & PLL531X_PDIV_MASK;
> +	sdiv = (pll_con0 >> PLL531X_SDIV_SHIFT) & PLL531X_SDIV_MASK;
> +	fdiv = (s32)(pll_con8 & PLL531X_FDIV_MASK);
> +
> +	if (fdiv >> 31)
> +		mdiv--;
> +
> +	fout *= ((u64)mdiv << 24) + (fdiv >> 8);
> +	do_div(fout, (pdiv << sdiv));
> +	fout >>= 24;
> +
> +	return (unsigned long)fout;
> +}
> +
> +static const struct clk_ops samsung_pll531x_clk_ops = {
> +	.recalc_rate = samsung_pll531x_recalc_rate, };
> +
>  static void __init _samsung_clk_register_pll(struct samsung_clk_provider
> *ctx,
>  				const struct samsung_pll_clock *pll_clk)  {
> @@ -1394,6 +1436,9 @@ static void __init _samsung_clk_register_pll(struct
> samsung_clk_provider *ctx,
>  		else
>  			init.ops = &samsung_pll2650xx_clk_ops;
>  		break;
> +	case pll_531x:
> +		init.ops = &samsung_pll531x_clk_ops;
> +		break;
>  	default:
>  		pr_warn("%s: Unknown pll type for pll clk %s\n",
>  			__func__, pll_clk->name);
> diff --git a/drivers/clk/samsung/clk-pll.h b/drivers/clk/samsung/clk-pll.h
> index ffd3d52c0dec..ce9d6f21f993 100644
> --- a/drivers/clk/samsung/clk-pll.h
> +++ b/drivers/clk/samsung/clk-pll.h
> @@ -41,6 +41,7 @@ enum samsung_pll_type {
>  	pll_0516x,
>  	pll_0517x,
>  	pll_0518x,
> +	pll_531x,
>  };
> 
>  #define PLL_RATE(_fin, _m, _p, _s, _k, _ks) \
> --
> 2.45.2