Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752356AbbKIFop (ORCPT ); Mon, 9 Nov 2015 00:44:45 -0500 Received: from mailgw02.mediatek.com ([210.61.82.184]:49070 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751883AbbKIFoQ (ORCPT ); Mon, 9 Nov 2015 00:44:16 -0500 X-Listener-Flag: 11101 From: Liguo Zhang To: Wolfram Sang CC: , Matthias Brugger , Eddie Huang , Xudong Chen , Sascha Hauer , , , , , Liguo Zhang Subject: [PATCH v2 2/2] i2c: mediatek: fix i2c multi transfer issue in high speed mode Date: Mon, 9 Nov 2015 13:43:59 +0800 Message-ID: <1447047839-5223-3-git-send-email-liguo.zhang@mediatek.com> X-Mailer: git-send-email 1.8.1.1.dirty In-Reply-To: <1447047839-5223-1-git-send-email-liguo.zhang@mediatek.com> References: <1447047839-5223-1-git-send-email-liguo.zhang@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: 2841 Lines: 90 For platform with auto restart support, when doing i2c multi transfer in high speed, for example, doing write-then-read transfer, the master code will occupy the first transfer, and the second transfer will be the read transfer, the write transfer will be discarded. So we should first send the master code, and then start i2c multi transfer. Signed-off-by: Liguo Zhang Reviewed-by: Eddie Huang --- drivers/i2c/busses/i2c-mt65xx.c | 45 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c index dc4aac6..249df86 100644 --- a/drivers/i2c/busses/i2c-mt65xx.c +++ b/drivers/i2c/busses/i2c-mt65xx.c @@ -53,6 +53,8 @@ #define I2C_FS_TIME_INIT_VALUE 0x1303 #define I2C_WRRD_TRANAC_VALUE 0x0002 #define I2C_RD_TRANAC_VALUE 0x0001 +#define I2C_TRAN_DEFAULT_VALUE 0x0001 +#define I2C_TRANAC_DEFAULT_VALUE 0x0001 #define I2C_DMA_CON_TX 0x0000 #define I2C_DMA_CON_RX 0x0001 @@ -365,6 +367,43 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk, return 0; } +static int mtk_i2c_send_master_code(struct mtk_i2c *i2c) +{ + int ret = 0; + + reinit_completion(&i2c->msg_complete); + + writew(I2C_CONTROL_RS | I2C_CONTROL_ACKERR_DET_EN | + I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN, + i2c->base + OFFSET_CONTROL); + + /* Clear interrupt status */ + writew(I2C_RS_TRANSFER | I2C_TRANSAC_COMP | I2C_HS_NACKERR | I2C_ACKERR, + i2c->base + OFFSET_INTR_STAT); + + /* Enable interrupt */ + writew(I2C_RS_TRANSFER | I2C_TRANSAC_COMP, i2c->base + + OFFSET_INTR_MASK); + + writew(I2C_TRAN_DEFAULT_VALUE, i2c->base + OFFSET_TRANSFER_LEN); + writew(I2C_TRANAC_DEFAULT_VALUE, i2c->base + OFFSET_TRANSAC_LEN); + + writew(I2C_TRANSAC_START | I2C_RS_MUL_CNFG, i2c->base + OFFSET_START); + + ret = wait_for_completion_timeout(&i2c->msg_complete, + i2c->adap.timeout); + + completion_done(&i2c->msg_complete); + + if (ret == 0) { + dev_dbg(i2c->dev, "send master code timeout.\n"); + mtk_i2c_init_hw(i2c); + return -ETIMEDOUT; + } + + return 0; +} + static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs, int num, int left_num) { @@ -539,6 +578,12 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap, } } + if (i2c->auto_restart && i2c->speed_hz > 400000) { + ret = mtk_i2c_send_master_code(i2c); + if (ret) + return ret; + } + while (left_num--) { if (!msgs->buf) { dev_dbg(i2c->dev, "data buffer is NULL.\n"); -- 1.8.1.1.dirty -- 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/