From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CCC67443AA2; Tue, 4 Aug 2026 10:36:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785839793; cv=none; b=lcuS3134z5vWYDfVm9irXuxpl0qwfydjjm7mqSr8GL3dtcnQ5FoKqom/ILvVSO/cVbYOL9Tj40DfR5MDUU6e15/LDOy86+IVPm1yRxgEHeJ0RkG8E2++zeCL9VpmwU6wecFnNdLkmmkTX7lFJRZHnt0YMYd87gb5o71AsV+1ZhU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785839793; c=relaxed/simple; bh=amHk4kQ9LXfJd111OmB8ZsrFZEMGzrFNLNblvY2ALXg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M8W2i8jdPgurqgv7Mys3qsXaPfMR0gtf/gmcH+4Y3jMV2LgHZUWecJD/0xWkIJYH36k8b6wTYjaj7z4w9i/cuvvMMnXThRDHTGKmd/Ub3QzDPWY6cifInx6PyzkW3+tJG8Ur5kjsBF1dVv2HD+LNShusGR7PtqN0Yxzb7ZUFcMg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=hLmEFhM0; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="hLmEFhM0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1785839791; x=1817375791; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=amHk4kQ9LXfJd111OmB8ZsrFZEMGzrFNLNblvY2ALXg=; b=hLmEFhM0J/ucNK9ehdZkaKGxxWgefa/QvqoTScZ/aTvWufK+X0j2Pbgg TbUBL56c/987uo1l3eFkizqOC5IIcFJEEPUJM5CoHV717PPsvAQHwtzQS 32WBGvjy79GbE0yWbee1aaHGeHk/IkThoJMUGeOnq1k4qR5hrYYcDbG/I G6hCItfpcL1MZW91aODV8ibGrCfLk+R/SCKHufpLVhpL1yZrSOpCoRFLp nTQdiAUepLtE1+jqFbdXyVLwDW+j9PyE8OSCk14QGJuV4Oj3oqHZFbHDX 9ME2iSYujP5hyQ+pqdpKv65zVB88tvQ5fmDYLHQFaAhNLgCyn4crd2e/T w==; X-CSE-ConnectionGUID: aAl6kX7ETCyBBTI+Vq8PBA== X-CSE-MsgGUID: mGqeZBloTuK9Cnt3LOg/zg== X-IronPort-AV: E=McAfee;i="6800,10657,11864"; a="90274931" X-IronPort-AV: E=Sophos;i="6.25,204,1779174000"; d="scan'208";a="90274931" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2026 03:36:30 -0700 X-CSE-ConnectionGUID: cmHZ3lP8QrqUHNZn/v+d+A== X-CSE-MsgGUID: xY8DisLZSo6XW8GssRge6w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,204,1779174000"; d="scan'208";a="284853730" Received: from black.igk.intel.com ([10.91.253.5]) by fmviesa002.fm.intel.com with ESMTP; 04 Aug 2026 03:36:28 -0700 Received: by black.igk.intel.com (Postfix, from userid 1001) id D28FC9B; Tue, 04 Aug 2026 12:36:27 +0200 (CEST) Date: Tue, 4 Aug 2026 12:36:27 +0200 From: Mika Westerberg To: Umesh Kumar Cc: Andi Shyti , Andy Shevchenko , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, bbhushan2@marvell.com Subject: Re: [RFC PATCH] i2c: designware: Enable SAR in slave mode for Multiple SAR controllers Message-ID: <20260804103627.GA69804@black.igk.intel.com> References: <20260804041842.3205356-1-ukumar@marvell.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260804041842.3205356-1-ukumar@marvell.com> Hi, On Tue, Aug 04, 2026 at 09:48:42AM +0530, Umesh Kumar wrote: > DesignWare controllers synthesised with the Multiple SAR feature (e.g. > Marvell CN20K) only acknowledge traffic to the primary slave address > (IC_SAR) when IC_ENABLE[19] (SAR_EN) is set. The slave enable path > writes only IC_ENABLE[0], so on such controllers the target never ACKs > its address and a remote master cannot reach it. > > Set SAR_EN together with ENABLE when entering slave mode. The bit is > reserved (and ignored) on single-SAR controllers, so existing users are > unaffected. > > Signed-off-by: Umesh Kumar > --- > RFC note: > > On our multi-SAR CN20K the slave only ACKs with IC_ENABLE[19] set. > Existing single-SAR users work without it, and the bit is reserved > there, so I've written it unconditionally. Would you prefer this > gated behind a per-device capability flag instead? The CN20K PCI > device enablement (which would set such a flag) can follow as a > separate series. No I think what you do here is fine, Acked-by: Mika Westerberg