Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932883AbcLMKDy (ORCPT ); Tue, 13 Dec 2016 05:03:54 -0500 Received: from mail-pg0-f45.google.com ([74.125.83.45]:34406 "EHLO mail-pg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932854AbcLMKDu (ORCPT ); Tue, 13 Dec 2016 05:03:50 -0500 From: Tin Huynh To: Jarkko Nikula , Andy Shevchenko , Mika Westerberg , Wolfram Sang Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, Loc Ho , Thang Nguyen , Phong Vo , patches@apm.com, Tin Huynh Subject: [PATCH V4] i2c: designware: fix wrong Tx/Rx FIFO for ACPI Date: Tue, 13 Dec 2016 17:03:34 +0700 Message-Id: <1481623414-19220-1-git-send-email-tnhuynh@apm.com> X-Mailer: git-send-email 1.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2202 Lines: 70 ACPI always sets Tx/Rx FIFO to 32. This configuration will cause problem if the IP core supports a FIFO size of less than 32. The driver should read the FIFO size from the IP and select the smaller one of the two. Signed-off-by: Tin Huynh --- drivers/i2c/busses/i2c-designware-platdrv.c | 27 ++++++++++++++++++++------- 1 files changed, 20 insertions(+), 7 deletions(-) Change from V3: -Use uppercase of FIFO instead of lowercase. -Fix the problem when IP core return 0 of FIFO. Change from V2: -Add a helper function to set FIFO size. Change from V1: -Revert the default 32 for FIFO, read parameter from IP core and pick the smaller one of the two. -Correct the title to describe new approach. diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 0b42a12..24032d6 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -150,6 +150,25 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare) return 0; } +static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id) +{ + u32 param, tx_fifo_depth, rx_fifo_depth; + + param = i2c_dw_read_comp_param(dev); + tx_fifo_depth = ((param >> 16) & 0xff) + 1; + rx_fifo_depth = ((param >> 8) & 0xff) + 1; + if (!dev->tx_fifo_depth) { + dev->tx_fifo_depth = tx_fifo_depth; + dev->rx_fifo_depth = rx_fifo_depth; + dev->adapter.nr = id; + } else if (tx_fifo_depth > 1) { + dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth, + tx_fifo_depth); + dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth, + rx_fifo_depth); + } +} + static int dw_i2c_plat_probe(struct platform_device *pdev) { struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev); @@ -246,13 +265,7 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) 1000000); } - if (!dev->tx_fifo_depth) { - u32 param1 = i2c_dw_read_comp_param(dev); - - dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1; - dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1; - dev->adapter.nr = pdev->id; - } + dw_i2c_set_fifo_size(dev, pdev->id); adap = &dev->adapter; adap->owner = THIS_MODULE; -- 1.7.1