From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: From: Alexander Stein To: Quentin Schulz Cc: linux-kernel@vger.kernel.org, jdelvare@suse.com, linux@roeck-us.net, jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, maxime.ripard@free-electrons.com, wens@csie.org, lee.jones@linaro.org, linux-hwmon@vger.kernel.org, linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, thomas.petazzoni@free-electrons.com, antoine.tenart@free-electrons.com Subject: Re: [PATCH v3 1/4] hwmon: iio_hwmon: delay probing with late_initcall Date: Tue, 26 Jul 2016 11:05:49 +0200 Message-ID: <5277864.qlyRKbC1Zy@ws-stein> In-Reply-To: <10d14cc4-26f1-8f2d-2997-3b2bc323c40e@free-electrons.com> References: <1469519027-11387-1-git-send-email-quentin.schulz@free-electrons.com> <209942367.uny0GxrY2s@ws-stein> <10d14cc4-26f1-8f2d-2997-3b2bc323c40e@free-electrons.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" List-ID: On Tuesday 26 July 2016 10:24:48, Quentin Schulz wrote: > On 26/07/2016 10:21, Alexander Stein wrote: > > On Tuesday 26 July 2016 09:43:44, 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. > > > > Would it work if iio_channel_get_all returning ENODEV is used for > > returning > > EPROBE_DEFER in iio_channel_get_all? Using late initcalls for > > driver/device > > dependencies seems not right for me at this place. > > Then what if the iio_channel_get_all is called outside of the probe of a > driver? We'll have to change the error code, things we are apparently > trying to avoid (see v2 patches' discussions). Maybe I didn't express my idea enough. I don't want to change the behavior of iio_channel_get_all at all. Just the result evaluation of iio_channel_get_all in iio_hwmon_probe. I have something link the patch below in mind. Best regards, Alexander --- diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c index b550ba5..e32d150 100644 --- a/drivers/hwmon/iio_hwmon.c +++ b/drivers/hwmon/iio_hwmon.c @@ -73,8 +73,12 @@ static int iio_hwmon_probe(struct platform_device *pdev) name = dev->of_node->name; channels = iio_channel_get_all(dev); - if (IS_ERR(channels)) - return PTR_ERR(channels); + if (IS_ERR(channels)) { + if (PTR_ERR(channels) == -ENODEV) + return -EPROBE_DEFER; + else + return PTR_ERR(channels); + } st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL); if (st == NULL) {