From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH] i2c: algo-bit: add support for I2C_M_STOP Date: Wed, 21 Jun 2017 16:30:18 +0200 Message-ID: <20170621143018.GA1571@katana> References: <20170617171238.19638-1-wsa+renesas@sang-engineering.com> <20170619103002.5d502c92@endymion> <20170620172810.h2anac45n5u3oova@ninjato> <20170621091843.657de813@endymion> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5vNYLRcllDrimb99" Return-path: Content-Disposition: inline In-Reply-To: <20170621091843.657de813@endymion> Sender: linux-renesas-soc-owner@vger.kernel.org To: Jean Delvare Cc: Wolfram Sang , linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org List-Id: linux-i2c@vger.kernel.org --5vNYLRcllDrimb99 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi Jean, > There's no problem with the scope. The problem is with the > initialization. The way you did, did_stop gets reset to false with > every iteration, which isn't what you want. Ouch, where is my brown paper bag... > I looked at how 10-bit addressing works again and in fact it is simply > impossible to not use repeated start when reading from a 10-bit address > slave. Only the first 2 bits of the 10-bit address are repeated in the > read part of the transaction. If there was a stop between the two parts > then there would be no way to know which 10-bit slave should send the > data. Which reminds me: Have you ever seen a 10-bit client device in the wild? I wanted to buy one for testing reasons but was not able to locate one. I only know a Renesas IP core which has 10-bit slave capability (but no driver support for that yet). Regards, Wolfram --5vNYLRcllDrimb99 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAllKgvUACgkQFA3kzBSg KbYmzQ//VBvyEJ1TNiyT93XFwKcEPa19lN+I3CxTGSP7QIFjmK04wDKlUs/TaKxG 2382m/y8lnLx7rC6p58hB507bqD9leQFke72nY/bwu+soFPAlka0LWbzIdmgfD20 g0cQ4n3w3Keq0lOQ+GO7H94qbTkozcz+06csSDrXPL8PiVeB0siClt6n/A8qR8VN thtZDP1nIwISEAbiwgxHFqmHTdbuWWmQ9DZUi6+zxMB/OHj5ckmV487EG0hKFRks 085I9fY/9KDN/gs0eMWoY6PXHjQoVoS8qNLb1MbB7E1O+njY7+Nx+pgJyBy7JnMA Y/rAo1MrPJB2LrzJxCqpbjiT5cdxOswuJIOsbztgtAePZxJjMtEv+dsE9d2j53Vc zgRrrUI9caiTajyLJ/AZt1QaDeBwm+oL51RDm4rHY6VPCgFpkVq1nXq+klVZiyBw bvVCykmsp4CdtqZPzdbF2fc5M4/bTidbbmbeOYej3ieUO1XEQvjM0ydW29j6Ln86 vpuww/bnmaCiMYMDKGgiR1PN153YMv9inqk9ocABMi/Y/s6/yqcMsmwuPCfAXBbI 8heN2HSCIiO+nK5BpObBo7VNkacUTe+IdqK/lQGLWHy1CIbWgjANdT3yZs3maUpA JeG9RvpqGTi2XDsm0vQ1tTWNEC82T98nukO3nWafWhb9noqz/VE= =bKjt -----END PGP SIGNATURE----- --5vNYLRcllDrimb99--