From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wolfram Sang Subject: [ 044/104] i2c: xiic: must always write 16-bit words to TX_FIFO Date: Mon, 6 May 2013 16:12:03 -0700 Message-Id: <20130506230048.139088480@linuxfoundation.org> In-Reply-To: <20130506230043.526528358@linuxfoundation.org> References: <20130506230043.526528358@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-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 @@ -312,10 +312,8 @@ 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); } }