From: Jonathan Cameron <jic23@kernel.org>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"William Breathitt Gray" <vilhelm.gray@gmail.com>,
kernel@pengutronix.de,
"Jonathan Cameron" <Jonathan.Cameron@huawei.com>,
linux-iio@vger.kernel.org,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
"Patrick Havelange" <patrick.havelange@essensium.com>,
"Kamel Bouhara" <kamel.bouhara@bootlin.com>,
linux-arm-kernel@lists.infradead.org,
"Syed Nayyar Waris" <syednwaris@gmail.com>,
"Oleksij Rempel" <linux@rempel-privat.de>,
"Jarkko Nikula" <jarkko.nikula@linux.intel.com>,
"David Lechner" <david@lechnology.com>,
"Fabrice Gasnier" <fabrice.gasnier@foss.st.com>,
"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
"Alexandre Torgue" <alexandre.torgue@foss.st.com>,
linux-stm32@st-md-mailman.stormreply.com,
"Jonathan Corbet" <corbet@lwn.net>,
linux-doc@vger.kernel.org,
"Ahmad Fatoum" <a.fatoum@pengutronix.de>,
"Felipe Balbi (Intel)" <balbi@kernel.org>,
"Raymond Tan" <raymond.tan@intel.com>,
"Benjamin Gaignard" <benjamin.gaignard@st.com>
Subject: Re: [PATCH v2 00/23] counter: cleanups and device lifetime fixes
Date: Tue, 28 Dec 2021 17:35:58 +0000 [thread overview]
Message-ID: <20211228173558.3702faa2@jic23-huawei> (raw)
In-Reply-To: <c8f6446e-748b-5845-ae60-5d6b8f3e8d39@metafoo.de>
On Mon, 27 Dec 2021 13:25:25 +0100
Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 12/27/21 10:45 AM, Uwe Kleine-König 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.
> >
> There used to be a time when GKH said that we do not want new driver
> classes. And all new subsystems should use bus since bus is a superset
> of class. This restriction has been eased since then.
>
> But it was around when the IIO subsystem was merged and since the
> counter subsystem originated from the IIO subsystem I assume it just
> copied this.
>
Yup. Discussion about this back then with one view being there
should never have been class in the first place.
https://lore.kernel.org/lkml/4B571DA4.6070603@cam.ac.uk/
For anyone who loves the history of these things...
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.
Ah well, opinions change over time!
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).
Jonathan
WARNING: multiple messages have this Message-ID (diff)
From: Jonathan Cameron <jic23@kernel.org>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"William Breathitt Gray" <vilhelm.gray@gmail.com>,
kernel@pengutronix.de,
"Jonathan Cameron" <Jonathan.Cameron@huawei.com>,
linux-iio@vger.kernel.org,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
"Patrick Havelange" <patrick.havelange@essensium.com>,
"Kamel Bouhara" <kamel.bouhara@bootlin.com>,
linux-arm-kernel@lists.infradead.org,
"Syed Nayyar Waris" <syednwaris@gmail.com>,
"Oleksij Rempel" <linux@rempel-privat.de>,
"Jarkko Nikula" <jarkko.nikula@linux.intel.com>,
"David Lechner" <david@lechnology.com>,
"Fabrice Gasnier" <fabrice.gasnier@foss.st.com>,
"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
"Alexandre Torgue" <alexandre.torgue@foss.st.com>,
linux-stm32@st-md-mailman.stormreply.com,
"Jonathan Corbet" <corbet@lwn.net>,
linux-doc@vger.kernel.org,
"Ahmad Fatoum" <a.fatoum@pengutronix.de>,
"Felipe Balbi (Intel)" <balbi@kernel.org>,
"Raymond Tan" <raymond.tan@intel.com>,
"Benjamin Gaignard" <benjamin.gaignard@st.com>
Subject: Re: [PATCH v2 00/23] counter: cleanups and device lifetime fixes
Date: Tue, 28 Dec 2021 17:35:58 +0000 [thread overview]
Message-ID: <20211228173558.3702faa2@jic23-huawei> (raw)
In-Reply-To: <c8f6446e-748b-5845-ae60-5d6b8f3e8d39@metafoo.de>
On Mon, 27 Dec 2021 13:25:25 +0100
Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 12/27/21 10:45 AM, Uwe Kleine-König 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.
> >
> There used to be a time when GKH said that we do not want new driver
> classes. And all new subsystems should use bus since bus is a superset
> of class. This restriction has been eased since then.
>
> But it was around when the IIO subsystem was merged and since the
> counter subsystem originated from the IIO subsystem I assume it just
> copied this.
>
Yup. Discussion about this back then with one view being there
should never have been class in the first place.
https://lore.kernel.org/lkml/4B571DA4.6070603@cam.ac.uk/
For anyone who loves the history of these things...
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.
Ah well, opinions change over time!
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).
Jonathan
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-12-28 17:30 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-27 9:45 [PATCH v2 00/23] counter: cleanups and device lifetime fixes Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-27 9:45 ` [PATCH v2 01/23] counter: Use container_of instead of drvdata to track counter_device Uwe Kleine-König
2021-12-28 17:14 ` Jonathan Cameron
2021-12-29 6:38 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 02/23] counter: ftm-quaddec: Drop unused platform_set_drvdata() Uwe Kleine-König
2021-12-28 17:37 ` Jonathan Cameron
2021-12-29 6:42 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 03/23] counter: microchip-tcb-capture: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 17:38 ` Jonathan Cameron
2021-12-28 17:38 ` Jonathan Cameron
2021-12-29 6:44 ` William Breathitt Gray
2021-12-29 6:44 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 04/23] counter: Provide a wrapper to access device private data Uwe Kleine-König
2021-12-27 11:02 ` Greg Kroah-Hartman
2021-12-27 11:34 ` Lars-Peter Clausen
2021-12-27 11:52 ` Greg Kroah-Hartman
2021-12-27 12:28 ` Lars-Peter Clausen
2021-12-28 18:01 ` Jonathan Cameron
2021-12-29 6:47 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 05/23] counter: 104-quad-8: Convert to counter_priv() wrapper Uwe Kleine-König
2021-12-28 18:02 ` Jonathan Cameron
2021-12-29 11:11 ` Uwe Kleine-König
2021-12-29 7:27 ` William Breathitt Gray
2021-12-29 11:15 ` Uwe Kleine-König
2021-12-29 22:40 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 06/23] counter: interrupt-cnt: " Uwe Kleine-König
2021-12-28 18:04 ` Jonathan Cameron
2021-12-29 7:34 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 07/23] counter: microchip-tcb-capture: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 18:05 ` Jonathan Cameron
2021-12-28 18:05 ` Jonathan Cameron
2021-12-29 7:35 ` William Breathitt Gray
2021-12-29 7:35 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 08/23] counter: intel-qep: " Uwe Kleine-König
2021-12-28 18:06 ` Jonathan Cameron
2021-12-29 7:35 ` William Breathitt Gray
2021-12-29 12:43 ` Jarkko Nikula
2021-12-27 9:45 ` [PATCH v2 09/23] counter: ftm-quaddec: " Uwe Kleine-König
2021-12-28 18:07 ` Jonathan Cameron
2021-12-29 7:36 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 10/23] counter: ti-eqep: " Uwe Kleine-König
2021-12-28 18:07 ` Jonathan Cameron
2021-12-29 7:45 ` William Breathitt Gray
2021-12-29 11:19 ` Uwe Kleine-König
2021-12-27 9:45 ` [PATCH v2 11/23] counter: stm32-lptimer-cnt: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 18:08 ` Jonathan Cameron
2021-12-28 18:08 ` Jonathan Cameron
2021-12-29 7:48 ` William Breathitt Gray
2021-12-29 7:48 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 12/23] counter: stm32-timer-cnt: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 18:08 ` Jonathan Cameron
2021-12-28 18:08 ` Jonathan Cameron
2021-12-29 7:48 ` William Breathitt Gray
2021-12-29 7:48 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 13/23] counter: Provide alternative counter registration functions Uwe Kleine-König
2021-12-27 12:16 ` Lars-Peter Clausen
2021-12-28 11:22 ` Uwe Kleine-König
2021-12-27 12:18 ` kernel test robot
2021-12-27 12:18 ` kernel test robot
2021-12-28 18:00 ` Jonathan Cameron
2021-12-29 11:27 ` Uwe Kleine-König
2021-12-29 12:07 ` Uwe Kleine-König
2021-12-29 13:49 ` Jarkko Nikula
2021-12-29 15:47 ` Uwe Kleine-König
2021-12-29 8:13 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 14/23] counter: Update documentation for new " Uwe Kleine-König
2021-12-28 18:12 ` Jonathan Cameron
2021-12-29 8:19 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 15/23] counter: 104-quad-8: Convert to new counter registration Uwe Kleine-König
2021-12-27 12:19 ` Lars-Peter Clausen
2021-12-28 11:06 ` Uwe Kleine-König
2021-12-28 18:17 ` Jonathan Cameron
2021-12-29 8:24 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 16/23] counter: interrupt-cnt: " Uwe Kleine-König
2021-12-27 10:59 ` Greg Kroah-Hartman
2021-12-27 11:21 ` Lars-Peter Clausen
2021-12-27 11:34 ` Greg Kroah-Hartman
2021-12-27 11:44 ` Lars-Peter Clausen
2021-12-27 21:09 ` Uwe Kleine-König
2021-12-28 18:18 ` Jonathan Cameron
2021-12-29 8:27 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 17/23] counter: intel-qep: " Uwe Kleine-König
2021-12-27 15:02 ` Jarkko Nikula
2021-12-28 10:56 ` Uwe Kleine-König
2021-12-29 12:42 ` Jarkko Nikula
2021-12-28 18:20 ` Jonathan Cameron
2021-12-29 8:29 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 18/23] counter: ftm-quaddec: " Uwe Kleine-König
2021-12-28 18:23 ` Jonathan Cameron
2021-12-29 8:33 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 19/23] counter: microchip-tcb-capture: " Uwe Kleine-König
2021-12-28 18:24 ` Jonathan Cameron
2021-12-29 8:36 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 20/23] counter: stm32-timer-cnt: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 18:25 ` Jonathan Cameron
2021-12-28 18:25 ` Jonathan Cameron
2021-12-29 8:37 ` William Breathitt Gray
2021-12-29 8:37 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 21/23] counter: stm32-lptimer-cnt: " Uwe Kleine-König
2021-12-27 9:45 ` Uwe Kleine-König
2021-12-28 18:26 ` Jonathan Cameron
2021-12-28 18:26 ` Jonathan Cameron
2021-12-29 8:39 ` William Breathitt Gray
2021-12-29 8:39 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 22/23] counter: ti-eqep: " Uwe Kleine-König
2021-12-28 18:29 ` Jonathan Cameron
2021-12-29 8:41 ` William Breathitt Gray
2021-12-27 9:45 ` [PATCH v2 23/23] counter: remove old and now unused registration API Uwe Kleine-König
2021-12-28 18:31 ` Jonathan Cameron
2021-12-29 8:43 ` William Breathitt Gray
2021-12-27 12:25 ` [PATCH v2 00/23] counter: cleanups and device lifetime fixes Lars-Peter Clausen
2021-12-27 12:25 ` Lars-Peter Clausen
2021-12-28 17:35 ` Jonathan Cameron [this message]
2021-12-28 17:35 ` Jonathan Cameron
2021-12-29 8:49 ` William Breathitt Gray
2021-12-29 8:49 ` William Breathitt Gray
2021-12-28 19:45 [PATCH v2 13/23] counter: Provide alternative counter registration functions kernel test robot
2022-01-06 10:53 ` Dan Carpenter
2022-01-06 10:53 ` Dan Carpenter
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