From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756314Ab3IDKGb (ORCPT ); Wed, 4 Sep 2013 06:06:31 -0400 Received: from cassiel.sirena.org.uk ([80.68.93.111]:35939 "EHLO cassiel.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752843Ab3IDKGa (ORCPT ); Wed, 4 Sep 2013 06:06:30 -0400 Date: Wed, 4 Sep 2013 11:06:06 +0100 From: Mark Brown To: Mike Turquette Cc: Lars-Peter Clausen , "linux-kernel@vger.kernel.org" , "Hennerich, Michael" , "linux-arm-kernel@lists.infradead.org" Message-ID: <20130904100606.GU3084@sirena.org.uk> References: <52209D1D.3080102@metafoo.de> <20130903232229.10934.60438@quantum> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bKO1kftFne8qVRsx" Content-Disposition: inline In-Reply-To: <20130903232229.10934.60438@quantum> X-Cookie: You love peace. User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 94.175.92.69 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: Clock framework deadlock with external SPI clockchip X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on cassiel.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --bKO1kftFne8qVRsx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 03, 2013 at 04:22:29PM -0700, Mike Turquette wrote: > Quoting Lars-Peter Clausen (2013-08-30 06:24:45) > > === Clock chip driver === === SPI master driver === > > clk_prepare_lock() > > spi_sync() > > wait_for_completion(X) > Is there a synchronous equivalent to spi_sync()? spi_sync() is synchronous? Obviously everything is asynchronous up to that point but the only way the driver can tell if the I/O completed is using spi_sync() or the equivalent thereof. If you're asking if there is a way of doing SPI I/O that isn't multi threaded then there isn't, in order to keep pushing transfers into the SPI controller to saturate the bus we have a high priority task to push more data in. SPI buses can be quite high bandwidth in some applications. --bKO1kftFne8qVRsx Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.21 (GNU/Linux) iQIcBAEBAgAGBQJSJwYLAAoJELSic+t+oim99LsP/RXG03uakYHHWgPiMfx35aWz fHHAxsuzYX5xUC4EBXoxU2N5xvhtM+k9ztNSnhGxTIChuVbZsQDZ73zAIvG5Fuf0 qlq5YBb5izUCpPFsn7Iye801SAesYQVo9iFCnTzMMx3cSXnVLxJOC0Pf37qx2Mwu YFddJmmIiSuMRrjdhof8DFsLm+/1/W2re6mwckhLgxsd3SmHYnCPY+TjbsCTB4WX QYpSbdL9WyqxlfySxQgaIBi3GFb+QlOx31SO6ZjO8psS4qXcbn7I52A+U0dcHrAj nLTfOBz9yELSFUs2gaOAJX643Q2YlQmYnigVDunQs5KduY/Fp7MsnZ6HRTLxu15y UYGmE5rbzYTHlvM/eXfFxpQalaEGY84qsn/f5pGPe6/r+TF1dmVvWAiRt+0Bg7Mx FJZD+xl9a5fVHRELsi5PtYRUyR1J31k5CY9YUTiAzQY6ZI26LO2T8UWOBOL/A/cr sAJGj7z646gZTZ8RbwoSVwaTjFqqvcMw7MtcEzbrdDKrIik5Hk6GVkay+/bEv2AZ pw6QuaWncJmlRyR5H4gYd/6PaIOF6KYOVQJz2jXbhmFZJfNM62Fs/bpe3kbeVE5F 3UZvQu8sr0BvCa1XJe28zqUzOQB1B9YrzfRmC3cFoL8cfc1rDbD36UuiG7ML03up 73ZyZ+JoK+AkSYkvoffW =OO50 -----END PGP SIGNATURE----- --bKO1kftFne8qVRsx--