From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Umesh Kumar <ukumar@marvell.com>
Cc: Andi Shyti <andi.shyti@kernel.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
bbhushan2@marvell.com, linux-i2c@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] i2c: designware: Enable SAR in slave mode for Multiple SAR controllers
Date: Mon, 17 Aug 2026 19:33:35 +0300 [thread overview]
Message-ID: <aoM33xFR6cvpAY2m@ashevche-desk.local> (raw)
In-Reply-To: <20260817162141.300658-1-ukumar@marvell.com>
On Mon, Aug 17, 2026 at 09:51:41PM +0530, Umesh Kumar wrote:
> DesignWare controllers synthesised with the Multiple SAR feature (e.g.
> Marvell CN20K) gate the primary slave address behind IC_ENABLE.SAR_EN
> (bit 19). Per the Synopsys DW_apb_i2c DataBook v2.03a (Multiple SAR
> feature), when this bit is set the core acknowledges the address matching
> IC_SAR; otherwise the address is NACKed. The slave enable path writes only
> IC_ENABLE.ENABLE (bit 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.
I gave my tag and it is absent here. What's going on?
Do you think the fix is not only that and requires a new round of review?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-08-17 16:33 UTC|newest]
Thread overview: 13+ 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
2026-08-12 10:37 ` [EXTERNAL] " Umesh Kumar
2026-08-12 11:45 ` [PATCH v3] " Umesh Kumar
2026-08-13 6:37 ` Andy Shevchenko
2026-08-17 8:40 ` [PATCH v4] " Umesh Kumar
2026-08-17 11:10 ` Andy Shevchenko
2026-08-17 16:21 ` [PATCH v5] " Umesh Kumar
2026-08-17 16:33 ` Andy Shevchenko [this message]
2026-08-18 14:18 ` [EXTERNAL] " Umesh Kumar
2026-08-18 14:43 ` [PATCH v6] " Umesh Kumar
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