Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758207AbYG2C0l (ORCPT ); Mon, 28 Jul 2008 22:26:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757965AbYG2C0S (ORCPT ); Mon, 28 Jul 2008 22:26:18 -0400 Received: from SpacedOut.fries.net ([67.64.210.234]:58119 "EHLO SpacedOut.fries.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757582AbYG2C0R (ORCPT ); Mon, 28 Jul 2008 22:26:17 -0400 Date: Mon, 28 Jul 2008 21:26:12 -0500 From: David Fries To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Evgeniy Polyakov Subject: [PATCH 23/30] W1: ds2490.c simplify and fix ds_touch_bit Message-ID: <20080729022612.GW24452@spacedout.fries.net> References: <20080729020433.GA24424@spacedout.fries.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="kZn00QyXxdr8qbeL" Content-Disposition: inline In-Reply-To: <20080729020433.GA24424@spacedout.fries.net> User-Agent: Mutt/1.5.4i X-Greylist: Sender is SPF-compliant, not delayed by milter-greylist-3.0 (SpacedOut.fries.net [127.0.0.1]); Mon, 28 Jul 2008 21:26:12 -0500 (CDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2843 Lines: 88 --kZn00QyXxdr8qbeL Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Simplify and fix ds_touch_bit. If a device is attached in the middle of a bus search the status register will return more than the default 16 bytes. The additional bytes indicate that it has detected a new device. The way ds_wait_status is coded, if it doesn't read 16 status bytes it returns an error value. ds_touch_bit then will detect that error and return an error. In that case it doesn't read the input buffer and returns uninitialized data. It doesn't stop there. The next transaction will not expect the extra byte in the input buffer and the short read will cause an error and clear out both the old byte and new data in the input buffer. Just ignore the value of ds_wait_status. It is still required to wait until ds2490 is again idle and there is data to read when ds_recv_data is called. This also removes the while loop. None of the other commands wait and verify that the issued command is in the status register. Signed-off-by: David Fries Signed-off-by: Evgeniy Polyakov --- drivers/w1/masters/ds2490.c | 21 ++++----------------- 1 files changed, 4 insertions(+), 17 deletions(-) diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c index 6bfd6a9..b1ae1a0 100644 --- a/drivers/w1/masters/ds2490.c +++ b/drivers/w1/masters/ds2490.c @@ -490,28 +490,15 @@ static int ds_set_pullup(struct ds_device *dev, int d= elay) =20 static int ds_touch_bit(struct ds_device *dev, u8 bit, u8 *tbit) { - int err, count; + int err; struct ds_status st; - u16 value =3D (COMM_BIT_IO | COMM_IM) | ((bit) ? COMM_D : 0); - u16 cmd; =20 - err =3D ds_send_control(dev, value, 0); + err =3D ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit ? COMM_D : 0), + 0); if (err) return err; =20 - count =3D 0; - do { - err =3D ds_wait_status(dev, &st); - if (err) - return err; - - cmd =3D st.command0 | (st.command1 << 8); - } while (cmd !=3D value && ++count < 10); - - if (err < 0 || count >=3D 10) { - printk(KERN_ERR "Failed to obtain status.\n"); - return -EINVAL; - } + ds_wait_status(dev, &st); =20 err =3D ds_recv_data(dev, tbit, sizeof(*tbit)); if (err < 0) --=20 1.4.4.4 --kZn00QyXxdr8qbeL Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (GNU/Linux) iD8DBQFIjn/EAI852cse6PARAsgeAJ91w5m5XYOQbRbkyRuIxNBLJQ86DwCgpY5x j9THufK9c6I4ObHXT2R9fww= =kKtq -----END PGP SIGNATURE----- --kZn00QyXxdr8qbeL-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/