From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Umesh Kumar <ukumar@marvell.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>,
Andi Shyti <andi.shyti@kernel.org>,
bbhushan2@marvell.com, linux-i2c@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] i2c: designware: Enable SAR in slave mode for Multiple SAR controllers
Date: Wed, 12 Aug 2026 10:16:29 +0300 [thread overview]
Message-ID: <anwdzfNei-2GhPrp@ashevche-desk.local> (raw)
In-Reply-To: <20260812034017.3654884-1-ukumar@marvell.com>
On Wed, Aug 12, 2026 at 09:10:17AM +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.
In the commit message and in the code comment below, can we refer to Synopsys
DataBook for I²C where this bit is described? Or is it Marvell custom bit?
--
With Best Regards,
Andy Shevchenko
prev parent reply other threads:[~2026-08-12 7:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-04 4:18 [RFC PATCH] i2c: designware: Enable SAR in slave mode for Multiple SAR controllers Umesh Kumar
2026-08-04 10:36 ` Mika Westerberg
2026-08-12 3:40 ` [PATCH v2] " Umesh Kumar
2026-08-12 7:16 ` Andy Shevchenko [this message]
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