Re: [PATCH v6] i2c: designware: Enable SAR in slave mode for Multiple SAR controllers

[Wolfram Sang <wsa+renesas@sang-engineering.com>]

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On Tue, Aug 18, 2026 at 08:13:06PM +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.
> 
> Signed-off-by: Umesh Kumar <ukumar@marvell.com>
> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Rebased to top-of-tree and applied to for-andi.

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>


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