From: Peng Fan <peng.fan@nxp.com>
To: Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
"Peng Fan (OSS)" <peng.fan@oss.nxp.com>,
Abel Vesa <abelvesa@kernel.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>, Jacky Bai <ping.bai@nxp.com>,
Ye Li <ye.li@nxp.com>, Aisheng Dong <aisheng.dong@nxp.com>
Cc: "linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
"imx@lists.linux.dev" <imx@lists.linux.dev>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Abel Vesa <abel.vesa@linaro.org>,
"S.J. Wang" <shengjiu.wang@nxp.com>,
Chancel Liu <chancel.liu@nxp.com>
Subject: RE: [PATCH v2 05/17] clk: imx: pll14xx: Add constraint for fvco frequency
Date: Mon, 13 May 2024 12:39:42 +0000 [thread overview]
Message-ID: <DU0PR04MB94176F2354DC55FF505305E688E22@DU0PR04MB9417.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <557d219a-dc00-4595-a3ff-a464908d5e03@prevas.dk>
> Subject: Re: [PATCH v2 05/17] clk: imx: pll14xx: Add constraint for fvco
> frequency
>
> On 10/05/2024 11.19, Peng Fan (OSS) wrote:
> > From: Shengjiu Wang <shengjiu.wang@nxp.com>
> >
> > The fvco frequency range is between 1600MHz and 3200MHz, without this
> > constraint the fvco may out of range, the real output frequency is no
> > accurate.
>
> Could you please point everybody in the direction of where that requirement
> is stated?
VCO has a range, we need update reference manual.
Regards,
Peng.
The imx8mp reference manual, for example, merely lists constraints
> for p, m, s and k.
>
>
> >
> > /* First try if we can get the desired rate from one of the static
> > entries */ @@ -193,6 +195,10 @@ static void
> imx_pll14xx_calc_settings(struct clk_pll14xx *pll, unsigned long rat
> > kdiv = pll1443x_calc_kdiv(mdiv, pdiv, sdiv, rate,
> prate);
> > fout = pll14xx_calc_rate(pll, mdiv, pdiv, sdiv, kdiv,
> prate);
> >
> > + fvco = fout << sdiv;
> > +
> > + if (fvco < 1600000000 || fvco > 3200000000)
> > + continue;
>
> If this is really a necessary constraint, it seems that one could just up-front
> compute the only possible value of s, or at least change the logic so that one
> loops over a smaller range of possible values of s.
>
> Rasmus
next prev parent reply other threads:[~2024-05-13 12:39 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-10 9:18 [PATCH v2 00/17] clk: imx: misc update/fix Peng Fan (OSS)
2024-05-10 9:18 ` [PATCH v2 01/17] clk: imx: composite-8m: Enable gate clk with mcore_booted Peng Fan (OSS)
2024-05-13 6:39 ` Sascha Hauer
2024-05-13 8:31 ` Peng Fan
2024-05-10 9:18 ` [PATCH v2 02/17] clk: imx: composite-93: keep root clock on when mcore enabled Peng Fan (OSS)
2024-05-10 9:18 ` [PATCH v2 03/17] clk: imx: composite-7ulp: Check the PCC present bit Peng Fan (OSS)
2024-05-13 6:54 ` Sascha Hauer
2024-05-10 9:18 ` [PATCH v2 04/17] clk: imx: fracn-gppll: fix fractional part of PLL getting lost Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 05/17] clk: imx: pll14xx: Add constraint for fvco frequency Peng Fan (OSS)
2024-05-13 12:13 ` Rasmus Villemoes
2024-05-13 12:39 ` Peng Fan [this message]
2024-05-13 12:28 ` Rasmus Villemoes
2024-05-13 12:42 ` Peng Fan
2024-05-13 12:40 ` Adam Ford
2024-05-10 9:19 ` [PATCH v2 06/17] clk: imx: pll14xx: use rate_table for audio plls Peng Fan (OSS)
2024-05-13 11:49 ` Rasmus Villemoes
2024-05-13 11:56 ` Peng Fan
2024-05-10 9:19 ` [PATCH v2 07/17] clk: imx: imx8mp-audiomix: remove sdma root clock Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 08/17] clk: imx: imx8mp: fix clock tree update of TF-A managed clocks Peng Fan (OSS)
2024-05-13 12:26 ` Ahmad Fatoum
2024-05-10 9:19 ` [PATCH v2 09/17] clk: imx: Remove CLK_SET_PARENT_GATE for DRAM mux for i.MX7D Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 10/17] clk: imx: add CLK_SET_RATE_PARENT for lcdif_pixel_src " Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 11/17] clk: imx: imx8mn: add sai7_ipg_clk clock settings Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 12/17] clk: imx: imx8mm: Change the 'nand_usdhc_bus' clock to non-critical one Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 13/17] clk: imx: imx8qxp: Add LVDS bypass clocks Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 14/17] clk: imx: imx8qxp: Add clock muxes for MIPI and PHY ref clocks Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 15/17] clk: imx: imx8qxp: Register dc0_bypass0_clk before disp clk Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 16/17] clk: imx: imx8qxp: Parent should be initialized earlier than the clock Peng Fan (OSS)
2024-05-10 9:19 ` [PATCH v2 17/17] clk: imx: fracn-gppll: update rate table Peng Fan (OSS)
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