Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755838AbdGCOKS (ORCPT ); Mon, 3 Jul 2017 10:10:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37816 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932588AbdGCNqc (ORCPT ); Mon, 3 Jul 2017 09:46:32 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jaedon Shin , Kamal Dasu , Wolfram Sang Subject: [PATCH 4.9 166/172] i2c: brcmstb: Fix START and STOP conditions Date: Mon, 3 Jul 2017 15:35:46 +0200 Message-Id: <20170703133422.106795515@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170703133414.260777365@linuxfoundation.org> References: <20170703133414.260777365@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2628 Lines: 87 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jaedon Shin commit 2de3ec4f1d4ba6ee380478055104eb918bd50cce upstream. The BSC data buffers to send and receive data are each of size 32 bytes or 8 bytes 'xfersz' depending on SoC. The problem observed for all the combined message transfer was if length of data transfer was a multiple of 'xfersz' a repeated START was being transmitted by BSC driver. Fixed this by appropriately setting START/STOP conditions for such transfers. Fixes: dd1aa2524bc5 ("i2c: brcmstb: Add Broadcom settop SoC i2c controller driver") Signed-off-by: Jaedon Shin Acked-by: Kamal Dasu Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-brcmstb.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) --- a/drivers/i2c/busses/i2c-brcmstb.c +++ b/drivers/i2c/busses/i2c-brcmstb.c @@ -465,6 +465,7 @@ static int brcmstb_i2c_xfer(struct i2c_a u8 *tmp_buf; int len = 0; int xfersz = brcmstb_i2c_get_xfersz(dev); + u32 cond, cond_per_msg; if (dev->is_suspended) return -EBUSY; @@ -481,10 +482,11 @@ static int brcmstb_i2c_xfer(struct i2c_a pmsg->buf ? pmsg->buf[0] : '0', pmsg->len); if (i < (num - 1) && (msgs[i + 1].flags & I2C_M_NOSTART)) - brcmstb_set_i2c_start_stop(dev, ~(COND_START_STOP)); + cond = ~COND_START_STOP; else - brcmstb_set_i2c_start_stop(dev, - COND_RESTART | COND_NOSTOP); + cond = COND_RESTART | COND_NOSTOP; + + brcmstb_set_i2c_start_stop(dev, cond); /* Send slave address */ if (!(pmsg->flags & I2C_M_NOSTART)) { @@ -497,13 +499,24 @@ static int brcmstb_i2c_xfer(struct i2c_a } } + cond_per_msg = cond; + /* Perform data transfer */ while (len) { bytes_to_xfer = min(len, xfersz); - if (len <= xfersz && i == (num - 1)) - brcmstb_set_i2c_start_stop(dev, - ~(COND_START_STOP)); + if (len <= xfersz) { + if (i == (num - 1)) + cond_per_msg = cond_per_msg & + ~(COND_RESTART | COND_NOSTOP); + else + cond_per_msg = cond; + } else { + cond_per_msg = (cond_per_msg & ~COND_RESTART) | + COND_NOSTOP; + } + + brcmstb_set_i2c_start_stop(dev, cond_per_msg); rc = brcmstb_i2c_xfer_bsc_data(dev, tmp_buf, bytes_to_xfer, pmsg); @@ -512,6 +525,8 @@ static int brcmstb_i2c_xfer(struct i2c_a len -= bytes_to_xfer; tmp_buf += bytes_to_xfer; + + cond_per_msg = COND_NOSTART | COND_NOSTOP; } }