Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933509AbbHDLpc (ORCPT ); Tue, 4 Aug 2015 07:45:32 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:58790 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S933034AbbHDLp2 (ORCPT ); Tue, 4 Aug 2015 07:45:28 -0400 X-Listener-Flag: 11101 From: Eddie Huang To: Wolfram Sang CC: , Matthias Brugger , Liguo Zhang , Xudong Chen , Sascha Hauer , , , , , Eddie Huang Subject: [PATCH 1/2] i2c: mediatek: Reset DMA engine in hardware init function Date: Tue, 4 Aug 2015 19:44:52 +0800 Message-ID: <1438688693-60275-2-git-send-email-eddie.huang@mediatek.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1438688693-60275-1-git-send-email-eddie.huang@mediatek.com> References: <1438688693-60275-1-git-send-email-eddie.huang@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1927 Lines: 58 Reset DMA in hardware init function to avoid unknown hardware state before do any I2C operation. Signed-off-by: Liguo Zhang Signed-off-by: Eddie Huang --- drivers/i2c/busses/i2c-mt65xx.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index 9920eef..055159d 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -1,6 +1,8 @@ /* * Copyright (c) 2014 MediaTek Inc. - * Author: Xudong Chen + * Author: + * Xudong Chen + * Liguo Zhang * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -59,6 +61,7 @@ #define I2C_DMA_START_EN 0x0001 #define I2C_DMA_INT_FLAG_NONE 0x0000 #define I2C_DMA_CLR_FLAG 0x0000 +#define I2C_DMA_HARD_RST 0x0002 #define I2C_DEFAULT_SPEED 100000 /* hz */ #define MAX_FS_MODE_SPEED 400000 @@ -81,6 +84,7 @@ enum DMA_REGS_OFFSET { OFFSET_INT_FLAG = 0x0, OFFSET_INT_EN = 0x04, OFFSET_EN = 0x08, + OFFSET_RST = 0x0c, OFFSET_CON = 0x18, OFFSET_TX_MEM_ADDR = 0x1c, OFFSET_RX_MEM_ADDR = 0x20, @@ -262,6 +266,10 @@ static void mtk_i2c_init_hw(struct mtk_i2c *i2c) I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN; writew(control_reg, i2c->base + OFFSET_CONTROL); writew(I2C_DELAY_LEN, i2c->base + OFFSET_DELAY_LEN); + + writel(I2C_DMA_HARD_RST, i2c->pdmabase + OFFSET_RST); + udelay(50); + writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_RST); } /* -- 1.7.9.5 -- 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/