From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v5 2/8] i2c: iproc: Add slave mode support Date: Tue, 2 Apr 2019 11:01:05 +0200 Message-ID: <20190402090105.GA2960@kunai> References: <20190214175725.60462-1-ray.jui@broadcom.com> <20190214175725.60462-3-ray.jui@broadcom.com> <20190327221452.GA15396@kunai> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="NzB8fVQJ5HfG6fxh" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Rayagonda Kokatanur Cc: Ray Jui , Rob Herring , Mark Rutland , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, Shreesha Rajashekar , Michael Cheng List-Id: devicetree@vger.kernel.org --NzB8fVQJ5HfG6fxh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > > >> + /* RANDOM SLAVE STRETCH time - 20ms*/ > > > > > > What is a "random stretch time"? 20ms sounds like a lot. Also, missing > > > space before comment terminator. > > > > > > > Rayagonda, > > > > Could you please help to comment on the choice of the 20 ms to allow > > clock stretch from the slave? In probably all cases, the slave should > > not need more than 1 ms? 20 ms does seem way too long as Wolfram pointed > > out. >=20 > In fact we are programming max slave stretch time ie 25ms, comment > should be correcting. > Its maximum time for slave to complete read/write operation, if slave > is done with read/write then clock will not be stretched further, it > will be released immediately. Ah, now I see. This is a protection against the slave stretching the clock forever. This makes sense. > Hence I feel no harm in programming max timeout value. I agree. "Random stretch" is just a bit confusing as a name. "Maximum" would have been more clear IMO. --NzB8fVQJ5HfG6fxh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlyjJM0ACgkQFA3kzBSg KbYwnRAAhyvKGZin7EPbNl42uih8M22BfSs+//ZzA92ckfe99z34MztaQzSbXRym wKO3ncesoIPM81IrYkwTY4lNTCRCLMxsmXMJbd518lumNp/4ZUp9sNSmoD8Z/61R e6YWJ7kysBz/iNjcbw8igaJLTvrZfV9IeSxuNdxQXCq9k9Whaa1yealO9CVVJiNU TpA16pFWbI7it7SuGwY2EEO/3asBqYj0CjjUthtS8kwqZ67MTVVzoK2cxstaoXec 1T9dhvRX++vIDpBoFlTRQH2ZGpSEQJmKosvNuagNIiKs/6Rcw+AbNLUYx9Z1qRwt FxYADEeszSLtFM1QoqTcwwERDap32YnZzhnnC61fpI+SIIKV6twClJWeZ/gPrU5u 0bxeAN8GwJ5OzxTAnoKNECwSUf0CsN2jnjbMv+1kXKmXJgYEhxQotgdxL2ywXeJ1 RL9SI2xApC47SAX6qJX/Z4ZtxT2aF1hdG7doy3rUu82e2VX9FcVyl/Qn1XQdgE6G h9JR5mqtOA5K9e3bDcKFQgeSFFCM+gKWd4LBfkEpsLR6EIzglwqcAtWYgbfp7kuD PSiacbJCZDTcbHMezQt2GI683MaDcIhwIYSPzgqv8KlHK9TXXHqm/+l3D1+RTrCz +aBK7knHXHplb37AOPZKSbjqCe9ksOJoIFIgAwaJu8rmZUs09X8= =MmnH -----END PGP SIGNATURE----- --NzB8fVQJ5HfG6fxh--