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From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Biju Das <biju.das.jz@bp.renesas.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH] mmc: renesas_sdhi: Add margins for main clock and hs clock
Date: Fri, 16 Sep 2022 19:40:09 +0100	[thread overview]
Message-ID: <YyTDCeL6FXB4UdKE@shikoro> (raw)
In-Reply-To: <OS0PR01MB592274E1073EDEB237A615B186489@OS0PR01MB5922.jpnprd01.prod.outlook.com>

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Hi Biju,

> diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
> index 6edbf5c161ab..539521f84e2f 100644
> --- a/drivers/mmc/host/renesas_sdhi_core.c
> +++ b/drivers/mmc/host/renesas_sdhi_core.c
> @@ -128,6 +128,7 @@ static unsigned int renesas_sdhi_clk_update(struct tmio_mmc_host *host,
>         struct clk *ref_clk = priv->clk;
>         unsigned int freq, diff, best_freq = 0, diff_min = ~0;
>         unsigned int new_clock, clkh_shift = 0;
> +       unsigned int new_clock_margin;
>         int i;
>  
>         /*
> @@ -156,7 +157,9 @@ static unsigned int renesas_sdhi_clk_update(struct tmio_mmc_host *host,
>          */
>         for (i = min(9, ilog2(UINT_MAX / new_clock)); i >= 0; i--) {
>                 freq = clk_round_rate(ref_clk, new_clock << i);
> -               if (freq > (new_clock << i)) {
> +               new_clock_margin = (new_clock << i) + ((new_clock << i) >> 10);
> +
> +               if (freq > new_clock_margin) {

new_clock_margin needs a comment explaining why we need it and set it to
that particular value. Otherwise looks good to me.

Thanks for doing it,

   Wolfram


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  reply	other threads:[~2022-09-16 18:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-13 16:15 [PATCH] mmc: renesas_sdhi: Add margins for main clock and hs clock Biju Das
2022-09-13 17:12 ` Geert Uytterhoeven
2022-09-13 17:31   ` Biju Das
2022-09-14  5:44     ` Biju Das
2022-09-14 15:44       ` Geert Uytterhoeven
2022-09-16 11:47         ` Biju Das
2022-09-16 16:04           ` Biju Das
2022-09-16 18:14             ` Biju Das
2022-09-16 18:40               ` Wolfram Sang [this message]
2022-09-19  8:33                 ` Biju Das

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