Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 3 Nov 2020 22:03:49 +0100
From:   Wolfram Sang <wsa@kernel.org>
To:     Michael Wu <michael.wu@vatics.com>
Cc:     Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        Morgan Chang <morgan.chang@vatics.com>
Subject: Re: [PATCH 2/2] i2c: designware: slave should do WRITE_REQUESTED
 before WRITE_RECEIVED
Message-ID: <20201103210349.GE1583@kunai>
Mail-Followup-To: Wolfram Sang <wsa@kernel.org>,
        Michael Wu <michael.wu@vatics.com>,
        Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        Morgan Chang <morgan.chang@vatics.com>
References: <20201030080420.28016-1-michael.wu@vatics.com>
 <20201030080420.28016-3-michael.wu@vatics.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
        protocol="application/pgp-signature"; boundary="0H629O+sVkh21xTi"
Content-Disposition: inline
In-Reply-To: <20201030080420.28016-3-michael.wu@vatics.com>
Precedence: bulk


--0H629O+sVkh21xTi
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline

Hi Michael,

> Documentation/i2c/slave-interface.rst says that I2C_SLAVE_WRITE_REQUESTED,
> which is mandatory, should be sent while the data did not arrive yet. It
> means in a write-request I2C_SLAVE_WRITE_REQUESTED should be reported
> before any I2C_SLAVE_WRITE_RECEIVED.

Correct.

> dev->status can be used to record the current state, especially Designware
> I2C controller has no interrupts to identify a write-request. This patch

Just double-checking: the designware HW does not raise an interrupt when
its own address + RW bit has been received?

Kind regards,

   Wolfram


--0H629O+sVkh21xTi
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=ISuO
-----END PGP SIGNATURE-----

--0H629O+sVkh21xTi--