From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Kleine-Budde Subject: Re: [PATCH 4/7] can: m_can: add a bit delay after setting CCCR_INIT bit Date: Mon, 03 Nov 2014 17:52:11 +0100 Message-ID: <5457B2BB.9050807@pengutronix.de> References: <1414579527-31100-1-git-send-email-b29396@freescale.com> <1414579527-31100-4-git-send-email-b29396@freescale.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="59wpUdW39w4bBDpUnfAOClG67Id7nAUck" Cc: wg@grandegger.com, varkabhadram@gmail.com, netdev@vger.kernel.org, socketcan@hartkopp.net, linux-arm-kernel@lists.infradead.org To: Dong Aisheng , linux-can@vger.kernel.org Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:36845 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752917AbaKCQwU (ORCPT ); Mon, 3 Nov 2014 11:52:20 -0500 In-Reply-To: <1414579527-31100-4-git-send-email-b29396@freescale.com> Sender: netdev-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --59wpUdW39w4bBDpUnfAOClG67Id7nAUck Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 10/29/2014 11:45 AM, Dong Aisheng wrote: > The spec mentions there may be a delay until the value written to > INIT can be read back due to the synchronization mechanism between the > two clock domains. But it does not indicate the exact clock cycles need= ed. > The 5us delay is a test value and seems ok. >=20 > Without the delay, CCCR.CCE bit may fail to be set and then the > initialization fail sometimes when do repeatly up and down. >=20 > Signed-off-by: Dong Aisheng Applied to can/master. Thanks, Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | --59wpUdW39w4bBDpUnfAOClG67Id7nAUck Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUV7K7AAoJECte4hHFiupUn7UP/00Pa4sLpqkvwkwI99EgLJHT 4fq+Gl3VC6JaycbwcuO/LN+75Ddgf3sXWjhVR9UJBERJ++eu4bEDf2Kxk7V0TdRb k/Qr+YaE9WbbweQaRcXEUuT39Hlj04LJVGga1j0X52e0NPJxW+ptCKz9PdDnxzAU ZxkB+zN46m1GP29e1WYSC0OcX60uuspSnkMC/Zr/FjV/LBLQQ8WztcZn/sBHs749 t3jGTS2lO2h1htzctKZ5gANBCfwRKGD2qGup07bwAANpLNOsHDy0iabZdcGHoSoY so54HvI0uY65Jal7X+/drVMZZ1+ItGipz45nPHNhPVjW98M5Q4Dm8Lq5Igd9T7o1 9QVxkpCQDJhos3rdJVpPkHe4IuxrvcXeIeZZ09eWhROb+23lxPw0REUUn8H6smyp WIQyt5SBNZyuJULZ2jV96e5fHVaMHTvjqf0ueGhIiBD9YndjOzgUAFtHKfex0OHB mUoCwmcInPzcecB+kArOYQCXMGpzDm4CyH2utqa3vGatqDhUrn/e22o1FSwixfmH 76hOcWIvHGdpEBBAM5JYO3+sZB/u8fjYe2bSXsBrMgAjBg8a69zPz/Z7LAfM+naA nKGjo0rFBhn1G+kIIyZ3Yrv5CEz5VRGEwNnaNXgMmsGAlSf8fqg7xVOOcR0WnXMs yNzh+2XVWoUnsBUwitdN =oRVY -----END PGP SIGNATURE----- --59wpUdW39w4bBDpUnfAOClG67Id7nAUck--