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[113.37.72.24]) by smtp.gmail.com with ESMTPSA id f16sm20733849pfv.191.2021.12.29.00.49.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Dec 2021 00:49:42 -0800 (PST) Date: Wed, 29 Dec 2021 17:49:30 +0900 From: William Breathitt Gray To: Jonathan Cameron Cc: Lars-Peter Clausen , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , kernel@pengutronix.de, Jonathan Cameron , linux-iio@vger.kernel.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Patrick Havelange , Kamel Bouhara , linux-arm-kernel@lists.infradead.org, Syed Nayyar Waris , Oleksij Rempel , Jarkko Nikula , David Lechner , Fabrice Gasnier , Maxime Coquelin , Alexandre Torgue , linux-stm32@st-md-mailman.stormreply.com, Jonathan Corbet , linux-doc@vger.kernel.org, Ahmad Fatoum , "Felipe Balbi (Intel)" , Raymond Tan , Benjamin Gaignard Subject: Re: [PATCH v2 00/23] counter: cleanups and device lifetime fixes Message-ID: References: <20211227094526.698714-1-u.kleine-koenig@pengutronix.de> <20211228173558.3702faa2@jic23-huawei> MIME-Version: 1.0 In-Reply-To: <20211228173558.3702faa2@jic23-huawei> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211229_004943_597873_410CEB33 X-CRM114-Status: GOOD ( 25.59 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============0770639488170453560==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============0770639488170453560== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ulhIPNF0Gpal2K//" Content-Disposition: inline --ulhIPNF0Gpal2K// Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Dec 28, 2021 at 05:35:58PM +0000, Jonathan Cameron wrote: > On Mon, 27 Dec 2021 13:25:25 +0100 > Lars-Peter Clausen wrote: >=20 > > On 12/27/21 10:45 AM, Uwe Kleine-K=C3=B6nig wrote: > > > [...] > > > > > > - I wonder why counter is a bus and not a class device type. There = is > > > no driver that would ever bind a counter device, is there? So > > > /sys/bus/counter/driver is always empty. > > > =20 > > There used to be a time when GKH said that we do not want new driver=20 > > classes. And all new subsystems should use bus since bus is a superset= =20 > > of class. This restriction has been eased since then. > >=20 > > But it was around when the IIO subsystem was merged and since the=20 > > counter subsystem originated from the IIO subsystem I assume it just=20 > > copied this. > >=20 >=20 > Yup. Discussion about this back then with one view being there > should never have been class in the first place. >=20 > https://lore.kernel.org/lkml/4B571DA4.6070603@cam.ac.uk/ >=20 > For anyone who loves the history of these things... >=20 > FWIW I think Greg suggested IIO should be a bus because we were hanging > a bunch of different types of device off a class and it was getting messy. > Kay then gave some history on class vs bus and suggested no new > subsystem should use class. >=20 > Ah well, opinions change over time! >=20 > Also interesting to see we were discussing a bridge to input all that > time ago and it's still not gone beyond various prototypes (with > exception of touch screens). >=20 > Jonathan Yes this is the reason: Counter subsystem just followed the structure of the IIO subsystem originally which is how it ended up as a bus; changing it to a class now would break userspace expectations so that is why it remains a bus still. William Breathitt Gray --ulhIPNF0Gpal2K// Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEk5I4PDJ2w1cDf/bghvpINdm7VJIFAmHMIRoACgkQhvpINdm7 VJKdGw/8DSuO6HGcXF2c1ChPZDJ+eF7e4FwznBOmwFZuui+Etz1RjciazjOGXRwC qi/+e6qNrOcZoQr5IQ+BNrSbMN+pBR9zFSsxBu1HdfrUAFq6uzmaYdC3cUtrY0OV jPPldinP4VhASWRokScS1xR+CFrP8YEwzsIljGAhRpYfXlm87EfY8xPcBLW/EOYb Ex4gBeYBaW3E5Ath2Ho6VMTb9Kcni+jIOSrxvhHv/XkewguyGJIXK8yy57BtwhDv lLUG8LoV43mFYYQJHi/+UvYC+qoHvvlHGUVPatA6/uRP8JnWp1QN3jO6bQulti3T SzWYjrOzjOqfomVfuUakaNK1yYNgjhVEH+gykqcqMC0J+DZtg3+1PyAtNNZ38hxe Vp9+lFTA/06YeWHBuW+bAiskbPZ6LRc3jPB6uSlxd4YRpCqr8K9CU9EaAo3SuPV1 zguKpB3drJ0Ifz6gjcr5mxDrCUoiseTd7Xi9uzDehuOet38g1PXfoisepp5KbYHl GKnqkVQzceOpLRpWkbv8ryhoMixVFG3mmwPzuxgkNinnEZWDFPskLNy7wAt7hIK9 0r2PalzvaFpP+mh+A6kZwAtiCRtTU54yjEL15QerAeo2Cpb7/SQ60PbGr899MWi5 8GpEW0v8QAjretoQiYeYiuYjcQqKJSiOgWY2FkzLYy01SBfBMSY= =PvzH -----END PGP SIGNATURE----- --ulhIPNF0Gpal2K//-- --===============0770639488170453560== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============0770639488170453560==--