From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753857AbcHPOAR (ORCPT ); Tue, 16 Aug 2016 10:00:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:3194 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753306AbcHPOAP (ORCPT ); Tue, 16 Aug 2016 10:00:15 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,529,1464678000"; d="scan'208";a="156561920" Subject: Re: [PATCH v3 2/3] i2c: designware: detect when dynamic tar update is possible To: Lucas De Marchi , linux-i2c@vger.kernel.org References: <1469743424-2480-1-git-send-email-lucas.demarchi@intel.com> <1469743424-2480-3-git-send-email-lucas.demarchi@intel.com> Cc: christian.ruppert@alitech.com, linux-kernel@vger.kernel.org, mika.westerberg@linux.intel.com, =?UTF-8?Q?Jos=c3=a9_Roberto_de_Souza?= From: Jarkko Nikula Message-ID: Date: Tue, 16 Aug 2016 17:00:12 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.2.0 MIME-Version: 1.0 In-Reply-To: <1469743424-2480-3-git-send-email-lucas.demarchi@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, + Wolfram On 07/29/2016 01:03 AM, Lucas De Marchi wrote: > This adapter can be synthesized with dynamic tar update enabled or disabled. > When enabled it is not necessary to disable the adapter to change the slave > address in some situations, which saves some time per transaction. > > There is no direct register to know if this feature is enabled but we can do it > indirectly by writing to the 10BIT_ADDR field in IC_CON: this field is > read only when dynamic tar update is enabled. > > Signed-off-by: Lucas De Marchi > Signed-off-by: José Roberto de Souza > --- > drivers/i2c/busses/i2c-designware-core.c | 37 ++++++++++++++++++++++---------- > drivers/i2c/busses/i2c-designware-core.h | 1 + > 2 files changed, 27 insertions(+), 11 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c > index 2c61585..a8408db 100644 > --- a/drivers/i2c/busses/i2c-designware-core.c > +++ b/drivers/i2c/busses/i2c-designware-core.c > @@ -388,6 +388,20 @@ int i2c_dw_init(struct dw_i2c_dev *dev) > /* configure the i2c master */ > dw_writel(dev, dev->master_cfg , DW_IC_CON); > > + /* > + * Test if dynamic TAR update is enabled in this controller by writing to Over 80 characters in this line. > + */ > + reg = dw_readl(dev, DW_IC_CON); > + dw_writel(dev, reg ^ DW_IC_CON_10BITADDR_MASTER, DW_IC_CON); > + > + if ((dw_readl(dev, DW_IC_CON) & DW_IC_CON_10BITADDR_MASTER) == > + (reg & DW_IC_CON_10BITADDR_MASTER)) { > + dev->dynamic_tar_update_enabled = true; > + dev_dbg(dev->dev, "Dynamic TAR update enabled"); > + } Is this possible to move to i2c_dw_probe()? I guess the enabled status doesn't change runtime? -- Jarkko