From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755180AbcHSOoh (ORCPT ); Fri, 19 Aug 2016 10:44:37 -0400 Received: from mail.kernel.org ([198.145.29.136]:50482 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754491AbcHSOoe (ORCPT ); Fri, 19 Aug 2016 10:44:34 -0400 Date: Fri, 19 Aug 2016 16:44:29 +0200 From: Sebastian Reichel To: One Thousand Gnomes Cc: Rob Herring , Greg Kroah-Hartman , Marcel Holtmann , Jiri Slaby , Pavel Machek , Peter Hurley , NeilBrown , "Dr . H . Nikolaus Schaller" , Arnd Bergmann , Linus Walleij , "open list:BLUETOOTH DRIVERS" , "linux-serial@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC PATCH 0/3] UART slave device bus Message-ID: <20160819144428.akddnwfl5g5qhtq3@earth> References: <20160818011445.22726-1-robh@kernel.org> <20160818202900.hyvm4hfxedifuefn@earth> <20160819052125.ze5zilppwoe3f2lx@earth> <20160819120305.4a3b1b54@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="xrml2jhy6jbpr337" Content-Disposition: inline In-Reply-To: <20160819120305.4a3b1b54@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.6.2-neo (2016-07-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --xrml2jhy6jbpr337 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Alan, On Fri, Aug 19, 2016 at 12:03:05PM +0100, One Thousand Gnomes wrote: > > I meant "Either some function similar to userspace's poll() is > > needed, ...". Something like uart_dev_wait_for_rx() >=20 > You can't really do that - it might never return and then how do > you want to handle timeouts and cleanups Well there could be some timeout. As I said, I was thinking about an API similar to poll(), but I agree, that a callback based API is probably the better solution. It's simpler to implement and in most cases simpler to use. > > Alternatively the rx function could be a callback, that > > is called when there is new data. >=20 > That's what the existing API gives you as an ldisc, it can't be > immediate in many cases however but must be buffered. I know and I think the ldisc API is fine in this regard. Also the buffering allows DMA, so that's obviously preferred. > > > I'm assuming the only immediate consumers are in-kernel. =20 > >=20 > > Yes, but the driver should be notified about incoming data. -- Sebastian --xrml2jhy6jbpr337 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJXtxtKAAoJENju1/PIO/qaAUEP/0pZt38WXTfx5lUI9bgBQYaW Hv+B23gbd76158vPyuEwuktxCoTXwvV1E3avLtycfnrsCxvzp3DhNI6pw5HP2lcB U4harpzxzP8aOwR8psWGs8t1JYJmzb7Y4aTn3Agi8pjPiS5lifvOlWpad07/4Z5k tMPi5wdTgDKG6Pt22loNJec86u40+OBgAtppwILqgiUYAzc4X+P0DZ3a4SMzQ7HJ P6bqk9OGmflrtWeiEc1kkAt3ElZxC+wRIRjlONpnJb5RichIVKMz6GasKkWNAvIG y8fTAf7cC2xaK0G1aHNPc1Yi8osCPEaHe5hLVwQSSoZmCLC0p6Ccs5hQZSCp/wIM 5R7x8X1V5LqBnNB0h/wiXhKQxo1mKCQIZdsCEc3Cqi5ZCUtBphh1AZu6Tj6b4B3m mFNRIAS+pk2hgcmrrGEznZem1cSMQ1iTMAxky8Dxl+ynKeQQeK1nFTG5bT5ppMxD 73G/b3AtdWkRlUgED5M5ZVVVQRcjdtpjMxUbsF8ePAfcMliOwIdkO6IyElxO/6TS pE0Xk0/oFj2puIgsTF3c9wN09BsmNq9pzgbdFBuuXOik6OPufbLLEx5YnzOIMzKv 3rgnwTLbzApSt7nqq3YtShgTV9P/KmuvewNcHt1M4rHJbPoYGyFSn/jBheu6T+iJ ZR/3KfUgGfsaWb31DNJD =ZKrp -----END PGP SIGNATURE----- --xrml2jhy6jbpr337--