From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v1 1/1] i2c: iproc: Add i2c repeated start capability Date: Wed, 4 Sep 2019 23:37:45 +0200 Message-ID: <20190904213745.GG23608@ninjato> References: <1565150941-27297-1-git-send-email-rayagonda.kokatanur@broadcom.com> <20190830125626.GC2870@ninjato> <3e70fa7e-de13-4edd-2e17-b7c56e91d220@broadcom.com> <20190831094940.GA1138@kunai> <540c4e2d-0dd5-5260-30b2-e1589b279d71@broadcom.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="EDJsL2R9iCFAt7IV" Return-path: Content-Disposition: inline In-Reply-To: <540c4e2d-0dd5-5260-30b2-e1589b279d71@broadcom.com> Sender: linux-kernel-owner@vger.kernel.org To: Ray Jui Cc: Rayagonda Kokatanur , 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, Florian Fainelli , Lori Hikichi , Icarus Chau , Shivaraj Shetty List-Id: devicetree@vger.kernel.org --EDJsL2R9iCFAt7IV Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > I think you are right that the controller does not seem to support > additional I2C features in addition to SMBUS. >=20 > However, my concern of switching to the smbus_xfer API is: >=20 > 1) Some customers might have used I2C_RDWR based API from i2cdev. Changing > from master_xfer to smbus_xfer may break the existing applications that a= re > already developed. Well, given that you add new quirks in the original patch here, you are kind of breaking it already. Most transfers which are not SMBus-alike transfers would now be rejected. For SMBus-alike transfers which are sent via I2C_RDWR (which is ugly), I have to think about it. > 2) The sound subsystem I2C regmap based implementation seems to be using > i2c_ based API instead of smbus_ based API. Does this mean this will also > break most of the audio codec drivers with I2C regmap API based usage? I don't think so. If you check regmap_get_i2c_bus() then it checks the adapter functionality and chooses the best transfer option then. I may be missing something but I would wonder if the sound system does something special and different. --EDJsL2R9iCFAt7IV Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl1wLqkACgkQFA3kzBSg KbbdPBAAsHYbJFSjXbArIzGj/6rYqzbUnvYeKqVHK/C1E7C1/89RAeVkba81NFsu PjHeTsrPaMQ6lK5Df79WK8I0EDf++K1Imv1edG64CamFTHqc60rVShO3ifPnQf8P XrOEAUxLEsoXjAqsUy9Nl2xU9roZxcglRdSSg+rlDsN6WRJ8bq0xg7I/7pPs0t/m DU+77rOjrqcj3mKJsMvcH/ay4tAYQGwXKalqLwkRuy6u5bQ98G/z9mPdGRwBXxx7 2lg61m1t05rmuU8PQZnnD1xB8syyt3/ivq4VWVs/9ghtAoTirMGtkhWu0SIQ17M5 KePWtCxia4A4rHQeEF6vdrbuZAcPqFy8ttnoccsUBBXLy4KYs2zguxiss0EXq95t QHW83RzcyxpPqqbVPAgtoQONVcFBLvJ3p5LDIHi/kgosLcTyyjTfre1vzRcG8j9S j/q++XaORKmfJ4evfK5AdbexTLnXGlUyXcRj0vQElOHxVOwk2PbjYAAq58XKsY9W 95LmlBMR2kDB/GCdZWGdTt29hyyhLgde4temx2eBCAqafAhAsPdFp8sFA2mEkaC4 h5rby01u7yD66c8hpI/4q5psgoj1j7fRctKsdtxb/S8P2sHcKZ6HygntSmmEb+WG BGd+gabtDbQBSHrOxqYrYBZVQFNf3YABNMFvC5LuvgMs3Ek59iM= =s2Lx -----END PGP SIGNATURE----- --EDJsL2R9iCFAt7IV--