From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759763Ab3EFXF3 (ORCPT ); Mon, 6 May 2013 19:05:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36412 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933095Ab3EFW7M (ORCPT ); Mon, 6 May 2013 18:59:12 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wolfram Sang Subject: [ 21/46] i2c: xiic: must always write 16-bit words to TX_FIFO Date: Mon, 6 May 2013 15:58:27 -0700 Message-Id: <20130506225822.882768175@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130506225820.628893970@linuxfoundation.org> References: <20130506225820.628893970@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable 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: Greg Kroah-Hartman --- 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); } }