Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758189AbaKTV3N (ORCPT ); Thu, 20 Nov 2014 16:29:13 -0500 Received: from mail-lb0-f172.google.com ([209.85.217.172]:55860 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758125AbaKTV3I (ORCPT ); Thu, 20 Nov 2014 16:29:08 -0500 From: Alexander Kochetkov To: linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, al.kochet@gmail.com Cc: Wolfram Sang , Tony Lindgren , Felipe Balbi Subject: [PATCH 4/4] i2c: omap: add notes related to i2c multimaster mode Date: Fri, 21 Nov 2014 01:28:45 +0400 Message-Id: <1416518925-20679-5-git-send-email-al.kochet@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1416518925-20679-1-git-send-email-al.kochet@gmail.com> References: <1416518925-20679-1-git-send-email-al.kochet@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org No functional changes. Signed-off-by: Alexander Kochetkov --- drivers/i2c/busses/i2c-omap.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 47103e7..4e3642c 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -304,6 +304,12 @@ static void __omap_i2c_init(struct omap_i2c_dev *dev) omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); /* + * NOTE: right after setting CON_EN, STAT_BB could be 0 while the + * bus is busy. It will be changed to 1 on the next IP FCLK clock. + * udelay(1) will be enough to fix that. + */ + + /* * Don't write to this register if the IE state is 0 as it can * cause deadlock. */ @@ -664,7 +670,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, if (!dev->b_hw && stop) w |= OMAP_I2C_CON_STP; - + /* + * NOTE: STAT_BB bit could became 1 here if another master occupy + * the bus. IP successfully complete transfer when the bus will be + * free again (BB reset to 0). + */ omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); /* -- 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/