Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755860Ab3EJOVw (ORCPT ); Fri, 10 May 2013 10:21:52 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57230 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755601Ab3EJOVk (ORCPT ); Fri, 10 May 2013 10:21:40 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Wolfram Sang" , "Steven A. Falco" Date: Fri, 10 May 2013 14:39:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [050/118] i2c: xiic: must always write 16-bit words to TX_FIFO In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:d51a:8785:aa0a:cebe X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1647 Lines: 47 3.2.45-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Steven A. Falco" commit c39e8e4354ce4daf23336de5daa28a3b01f00aa6 upstream. The TX_FIFO register is 10 bits wide. The lower 8 bits are the data to be written, while the upper two bits are flags to indicate stop/start. The driver apparently attempted to optimize write access, by only writing a byte in those cases where the stop/start bits are zero. However, we have seen cases where the lower byte is duplicated onto the upper byte by the hardware, which causes inadvertent stop/starts. This patch changes the write access to the transmit FIFO to always be 16 bits wide. Signed off by: Steven A. Falco Signed-off-by: Wolfram Sang Signed-off-by: Ben Hutchings --- drivers/i2c/busses/i2c-xiic.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/drivers/i2c/busses/i2c-xiic.c +++ b/drivers/i2c/busses/i2c-xiic.c @@ -311,10 +311,8 @@ static void xiic_fill_tx_fifo(struct xii /* last message in transfer -> STOP */ data |= XIIC_TX_DYN_STOP_MASK; dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); - - xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); - } else - xiic_setreg8(i2c, XIIC_DTR_REG_OFFSET, data); + } + xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); } } -- 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/