Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761947AbYGKNzp (ORCPT ); Fri, 11 Jul 2008 09:55:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759207AbYGKNsT (ORCPT ); Fri, 11 Jul 2008 09:48:19 -0400 Received: from zbr.yandex.ru ([213.180.219.33]:34979 "EHLO gavana.yandex.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759410AbYGKNrz (ORCPT ); Fri, 11 Jul 2008 09:47:55 -0400 From: Evgeniy Polyakov To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Fries , Evgeniy Polyakov Subject: [PATCH 23/30] W1: ds2490.c simplify and fix ds_touch_bit Date: Fri, 11 Jul 2008 17:51:38 +0400 Message-Id: <1215784307412-git-send-email-johnpol@2ka.mipt.ru> X-Mailer: git-send-email 1.5.2.5 In-Reply-To: <12157843054074-git-send-email-johnpol@2ka.mipt.ru> References: <12157843054074-git-send-email-johnpol@2ka.mipt.ru> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2379 Lines: 69 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 delay) static int ds_touch_bit(struct ds_device *dev, u8 bit, u8 *tbit) { - int err, count; + int err; struct ds_status st; - u16 value = (COMM_BIT_IO | COMM_IM) | ((bit) ? COMM_D : 0); - u16 cmd; - err = ds_send_control(dev, value, 0); + err = ds_send_control(dev, COMM_BIT_IO | COMM_IM | (bit ? COMM_D : 0), + 0); if (err) return err; - count = 0; - do { - err = ds_wait_status(dev, &st); - if (err) - return err; - - cmd = st.command0 | (st.command1 << 8); - } while (cmd != value && ++count < 10); - - if (err < 0 || count >= 10) { - printk(KERN_ERR "Failed to obtain status.\n"); - return -EINVAL; - } + ds_wait_status(dev, &st); err = ds_recv_data(dev, tbit, sizeof(*tbit)); if (err < 0) -- 1.4.4.4 -- 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/