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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i7Eua-0008GA-Vh; Mon, 09 Sep 2019 08:20:37 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i7EuX-0008FW-LB for linux-arm-kernel@lists.infradead.org; Mon, 09 Sep 2019 08:20:34 +0000 Received: from kernel.org (unknown [104.132.0.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B704D20678; Mon, 9 Sep 2019 08:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568017232; bh=hUjMFYDt15aaG0KcZhtWuZvcPW21IIr+paV7LbXYOQk=; h=In-Reply-To:References:Cc:To:From:Subject:Date:From; b=LXLYTbc0hnvTUjlZJEbqYjodBBHPV/b8iEKfS7UbLV2zb1p75QOnTkeUJhQRRxc6M 8GJWSw0+K+FqKPGS3JLrn1fTiPDdflA3APu33YlNsim7A72E9EarwUu2vCFbQheA93 YNiqaT/PfggdraDmM5l56vTOFLEUmUh794cM81Xc= MIME-Version: 1.0 In-Reply-To: References: <20190906172452.D1ED620838@mail.kernel.org> To: Daniel Baluta , Leonard Crestez , Peng Fan , Shawn Guo From: Stephen Boyd Subject: Re: [PATCH] clk: imx: pll14xx: Fix quick switch of S/K parameter User-Agent: alot/0.8.1 Date: Mon, 09 Sep 2019 01:20:31 -0700 Message-Id: <20190909082032.B704D20678@mail.kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190909_012033_711757_7CA4934B X-CRM114-Status: GOOD ( 15.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Aisheng Dong , Jacky Bai , Michael Turquette , "linux-clk@vger.kernel.org" , dl-linux-imx , Viorel Suman , Fabio Estevam , "kernel@pengutronix.de" , "linux-arm-kernel@lists.infradead.org" , Abel Vesa Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Quoting Leonard Crestez (2019-09-06 12:36:47) > On 06.09.2019 20:24, Stephen Boyd wrote: > > Quoting Leonard Crestez (2019-09-04 02:49:18) > >> The PLL14xx on imx8m can change the S and K parameter without requiring > >> a reset and relock of the whole PLL. > >> > >> Fix clk_pll144xx_mp_change register reading and use it for pll1443 as > >> well since no reset+relock is required on K changes either. > >> > >> Signed-off-by: Leonard Crestez > >> --- > >> drivers/clk/imx/clk-pll14xx.c | 40 +++++++---------------------------- > >> 1 file changed, 8 insertions(+), 32 deletions(-) > >> > >> The PLLs are currently table-based and none of the entries differ only > >> in S/K so further work would be required to make use of this. The > >> prospective user is audio doing tiny freq adjustments and there is no > >> standard API for that. > > > > sub-Hz adjustments? > > Maybe at the audio level? The PLL itself runs at ~400Mhz so wouldn't > need sub-hz adjustment. > > My understanding is that adjustments would be made based on an external > clock so if CLK framework rounds to 1hz then it would just take longer > for adjustment to kick in. Ok. > > >> Lacking users is not a good reason to carry broken code around. > > > > Maybe add a Fixes tag so if anyone wants to use it in LTS kernels there > > might be a chance that they'll find this patch mention code they're > > using. > > It doesn't meet stable kernel rules because it doesn't "fix a real bug > that bothers people" but it's still technically a fix: > > Fixes: 8646d4dcc7fb ("clk: imx: Add PLLs driver for imx8mm soc") > Sure. Thanks! I assume Shawn will pick this up. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel