From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v3 4/5] i2c: davinci: use bus recovery infrastructure Date: Wed, 18 Mar 2015 21:31:51 +0100 Message-ID: <20150318203151.GA12072@katana> References: <1417448047-15236-1-git-send-email-grygorii.strashko@ti.com> <1417448047-15236-5-git-send-email-grygorii.strashko@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="Q68bSM7Ycu6FN28Q" Return-path: Content-Disposition: inline In-Reply-To: <1417448047-15236-5-git-send-email-grygorii.strashko-l0cyMroinI0@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grygorii Strashko Cc: Sekhar Nori , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Kevin Hilman , Santosh Shilimkar , Murali Karicheri List-Id: linux-i2c@vger.kernel.org --Q68bSM7Ycu6FN28Q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, so, the bus recovery patches look fine to me in general. It is only this one question left which I always had with bus recovery. Maybe you guys can join me thinking about it. > @@ -376,8 +366,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) > dev->adapter.timeout); > if (r == 0) { > dev_err(dev->dev, "controller timed out\n"); > - davinci_i2c_recover_bus(dev); > - i2c_davinci_init(dev); > + i2c_recover_bus(adap); > dev->buf_len = 0; > return -ETIMEDOUT; The I2C specs say in 3.1.16 that the recovery procedure should be used when SDA is stuck low. So, I do wonder if we should apply the recovery after a timeout. Stuck SDA might be one reason for timeout, but there may be others... Thanks, Wolfram --Q68bSM7Ycu6FN28Q Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVCeC2AAoJEBQN5MwUoCm2RAUQAJoY3djE5kdIc4SzhTystpwy DN9XAGo56Bo5t3fGeB4cyuT8xZsxhq5fq49l62OmIfpL0gZBMpju8gWXWPRpF5Jp K6crm4Z9qFyo7QMzBanqir3iklYYsTHAh3msQS72nL1QzYkPxc05Viz4WGGKkBob Fw2YLrjg3IF/rN+2btA/KIiW9Z8Qx38Pp3EbLwcWwmIIEVTi/zDOkX2+yTO1w6r7 KXVdXwyYMNcUvdP0hF6zLRoX0rcjrkJwq7MU/q1XJwPm0fNWr7hPahMuaKrVHqXH esyOjnqCRrq8UAyChLgkbzcdnZWat/4LppzMG9fI1XZUIUTbjIElvcvbuj8BfUuF uS4ihPw1jlqfNX37E6TEO4Ufzbm22dMgXuCrV/eFqPpynezziWjkf7k7skGRJpDm uK5gS9490XOCdPGIZdHVW/Pn523RwVh19dhfW7FHF2wBaDL+7Dd31vhKDT1/TNoQ KNOil6l6qlwYwDIqguDry0Se8bpCbtI2qK7+QiCIR6RZ/bO++xhgFlBub2bbZmD6 2q1VQpLfgnfGSXp5isSKJr/u3d7P0tGUM2DvtG8kf8QWVUXXx8RxVXf2com2rQ9e KnymLvGUTdeoSJdtFQo0RTJJv7wkjhEIZnD5iwAcEIKSE38ULMgs3TDQcpzw/XTP X+m53oZ1P9mGLl3Q6xWe =ydUi -----END PGP SIGNATURE----- --Q68bSM7Ycu6FN28Q--