From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Krummsdorf Michael To: =?iso-8859-1?Q?Uwe_Kleine-K=F6nig?= , Stefan Wahren CC: Fabio Estevam , Michael Turquette , Stephen Boyd , Fabio Estevam , Shawn Guo , "linux-clk@vger.kernel.org" , "kernel@pengutronix.de" Subject: AW: [PATCH] clk: mxs: ensure that i.MX28's ref_io clks are not operated too fast Date: Mon, 8 May 2017 09:53:28 +0000 Message-ID: References: <20170503185625.10297-1-u.kleine-koenig@pengutronix.de> <20170505072529.a3z4gonsygg3wqfx@pengutronix.de> <185bc71b-f986-9dd1-3a56-a525f2f09fc7@i2se.com> <20170505201039.uyk2ie6zyfrdafgo@pengutronix.de> In-Reply-To: <20170505201039.uyk2ie6zyfrdafgo@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" List-ID: Hello Uwe,=20 > (adding Michael Krummsdorf who authored a different patch for the same > problem back in 2014 which Stefan found in TQ's patch stack.) thanks for adding me. Back then I narrowed the issue down to two conditions: * ref_io had to be clock source and * ssp clock div had to be 1 Limiting ssp clock div to be at least 2 eliminated the error. So in the driver I capped clk_freq to 480 MHz / 2. I did not consider changing ref_io frequency. Best regards, i.A. Michael Krummsdorf Entwicklung Standort Leipzig Tel. +49 341 308598-27, Fax +49 341 308598-11, Friedrich-List-Platz 2, 04103 Leipzig mailto:michael.krummsdorf@tq-group.com =20 TQ-Systems GmbH M=FChlstra=DFe 2, Gut Delling, 82229 Seefeld Amtsgericht M=FCnchen, HRB 105018 Sitz der Gesellschaft: Seefeld Gesch=E4ftsf=FChrer: Detlef Schneider, R=FCdiger Stahl, Stefan Schneider www.tq-group.com Besuchen Sie uns: Intersolar Europe, M=FCnchen, 31. Mai - 2. Juni 2017, Halle B2, Stand B2.23= 4 MT-CONNECT, N=FCrnberg, 21. - 22. Juni 2017, Halle 10.1, Stand 10.1-116