From: maxime.ripard@free-electrons.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [v2,1/4] hwmon: iio_hwmon: defer probe when no channel is found
Date: Mon, 18 Jul 2016 12:02:32 +0200 [thread overview]
Message-ID: <20160718100232.GE4199@lukather> (raw)
In-Reply-To: <20160716170013.GA27490@roeck-us.net>
Hi Guenter,
On Sat, Jul 16, 2016 at 10:00:13AM -0700, Guenter Roeck wrote:
> On Fri, Jul 15, 2016 at 11:59:11AM +0200, Quentin Schulz wrote:
> > iio_channel_get_all returns -ENODEV when it cannot find either phandles and
> > properties in the Device Tree or channels whose consumer_dev_name matches
> > iio_hwmon in iio_map_list. The iio_map_list is filled in by iio drivers
> > which might be probed after iio_hwmon.
> >
> > It is better to defer the probe of iio_hwmon if such error is returned by
> > iio_channel_get_all in order to let a chance to iio drivers to expose
> > channels in iio_map_list.
> >
> > Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
> > ---
> >
> > No modifications for this patch since we did not settled for a solution.
> > What should we do?
> >
> AFAICS the only thing we can do is to replace module_platform_driver() with
> its explicitly coded variant, and to use use late_initcall() instead of
> module_init().
I thought this kind of changes to the driver init time were
discouraged these days?
> Anything else would result in endless probe deferrals if there are
> no channels.
Well, technically, not endless. AFAIK, the kernel only retries when a
new driver is probed, which should hopefully settle down rather
quickly.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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next prev parent reply other threads:[~2016-07-18 10:02 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-15 9:59 [PATCH v2 0/4] add support for Allwinner SoCs ADC Quentin Schulz
2016-07-15 9:59 ` [PATCH v2 1/4] hwmon: iio_hwmon: defer probe when no channel is found Quentin Schulz
2016-07-16 17:00 ` [v2,1/4] " Guenter Roeck
2016-07-18 10:02 ` Maxime Ripard [this message]
2016-07-18 13:29 ` Guenter Roeck
2016-07-15 9:59 ` [PATCH v2 2/4] iio: adc: add support for Allwinner SoCs ADC Quentin Schulz
2016-07-18 12:57 ` Maxime Ripard
2016-07-19 9:04 ` Quentin Schulz
2016-07-19 12:40 ` Maxime Ripard
2016-07-18 13:18 ` Jonathan Cameron
2016-07-19 8:33 ` Quentin Schulz
2016-07-20 14:57 ` Jonathan Cameron
2016-07-21 12:15 ` Quentin Schulz
2016-07-23 6:37 ` Jonathan Cameron
2016-07-20 12:37 ` Quentin Schulz
2016-07-20 14:15 ` Crt Mori
2016-07-20 14:59 ` Jonathan Cameron
2016-07-15 9:59 ` [PATCH v2 3/4] mfd: " Quentin Schulz
2016-07-18 13:02 ` Maxime Ripard
2016-07-19 12:04 ` Quentin Schulz
2016-07-18 13:25 ` Jonathan Cameron
2016-07-19 7:31 ` Lee Jones
2016-07-20 15:01 ` Jonathan Cameron
2016-07-21 12:12 ` Lee Jones
2016-07-21 20:08 ` Maxime Ripard
2016-07-22 13:55 ` Lee Jones
2016-07-23 6:42 ` Jonathan Cameron
2016-07-25 9:55 ` Maxime Ripard
2016-07-19 8:35 ` Quentin Schulz
2016-07-15 9:59 ` [PATCH v2 4/4] hwmon: iio: add label for channels read by iio_hwmon Quentin Schulz
2016-07-15 14:03 ` Guenter Roeck
2016-07-15 14:36 ` Quentin Schulz
2016-07-16 2:53 ` Guenter Roeck
2016-07-18 12:24 ` Jonathan Cameron
2016-07-19 6:55 ` Quentin Schulz
2016-07-20 14:49 ` Jonathan Cameron
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