Messages in this thread Patch in this message | | | Subject | Re: Applied "regulator: core: Link consumer with regulator driver" to the regulator tree | From | Marek Szyprowski <> | Date | Mon, 9 Jul 2018 13:17:51 +0200 |
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Dear All,
On 2018-07-05 19:55, Mark Brown wrote: > The patch > > regulator: core: Link consumer with regulator driver > > has been applied to the regulator tree at > > https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git > > All being well this means that it will be integrated into the linux-next > tree (usually sometime in the next 24 hours) and sent to Linus during > the next merge window (or sooner if it is a bug fix), however if > problems are discovered then the patch may be dropped or reverted. > > You may get further e-mails resulting from automated or manual testing > and review of the tree, please engage with people reporting problems and > send followup patches addressing any issues that are reported if needed. > > If any updates are required or you are submitting further changes they > should be sent as incremental updates against current git, existing > patches will not be replaced. > > Please add any relevant lists and maintainers to the CCs when replying > to this mail. > > Thanks, > Mark > > >From ed1ae2dd9f242c7a36e8e39100f6a7f6bcdfdd89 Mon Sep 17 00:00:00 2001 > From: pascal paillet <p.paillet@st.com> > Date: Thu, 5 Jul 2018 14:25:56 +0000 > Subject: [PATCH] regulator: core: Link consumer with regulator driver > > Add a device link between the consumer and the driver so that > the consumer is not suspended before the driver. The goal is to avoid > implementing suspend_late ops in regulator drivers. > > Signed-off-by: pascal paillet <p.paillet@st.com> > Signed-off-by: Mark Brown <broonie@kernel.org>
This patch triggers the following warning on several Exynos SoC based boards:
------------[ cut here ]------------ WARNING: CPU: 1 PID: 1 at drivers/base/core.c:108 device_is_dependent+0xa4/0xb4 Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc3-next-20180706 #112 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [<c0113200>] (unwind_backtrace) from [<c010edd0>] (show_stack+0x10/0x14) [<c010edd0>] (show_stack) from [<c0a4b6e8>] (dump_stack+0x98/0xc4) [<c0a4b6e8>] (dump_stack) from [<c0127b90>] (__warn+0x10c/0x124) [<c0127b90>] (__warn) from [<c0127cbc>] (warn_slowpath_null+0x40/0x48) [<c0127cbc>] (warn_slowpath_null) from [<c0580464>] (device_is_dependent+0xa4/0xb4) [<c0580464>] (device_is_dependent) from [<c058037c>] (device_for_each_child+0x50/0x94) [<c058037c>] (device_for_each_child) from [<c05803e0>] (device_is_dependent+0x20/0xb4) [<c05803e0>] (device_is_dependent) from [<c0581bcc>] (device_link_add+0x70/0x2a8) [<c0581bcc>] (device_link_add) from [<c04e4134>] (_regulator_get+0xbc/0x270) [<c04e4134>] (_regulator_get) from [<c04e4350>] (regulator_bulk_get+0x60/0xcc) [<c04e4350>] (regulator_bulk_get) from [<c05b4e40>] (wm8994_i2c_probe+0x334/0x8ec) [<c05b4e40>] (wm8994_i2c_probe) from [<c06d8d98>] (i2c_device_probe+0x240/0x2b8) [<c06d8d98>] (i2c_device_probe) from [<c05857d8>] (driver_probe_device+0x2dc/0x4ac) [<c05857d8>] (driver_probe_device) from [<c0585ad0>] (__driver_attach+0x128/0x144) [<c0585ad0>] (__driver_attach) from [<c0583668>] (bus_for_each_dev+0x68/0xb4) [<c0583668>] (bus_for_each_dev) from [<c0584968>] (bus_add_driver+0x1a8/0x268) [<c0584968>] (bus_add_driver) from [<c0586c48>] (driver_register+0x78/0x10c) [<c0586c48>] (driver_register) from [<c06d9ca4>] (i2c_register_driver+0x3c/0xa8) [<c06d9ca4>] (i2c_register_driver) from [<c0103188>] (do_one_initcall+0x8c/0x4b0) [<c0103188>] (do_one_initcall) from [<c0f01268>] (kernel_init_freeable+0x3e4/0x570) [<c0f01268>] (kernel_init_freeable) from [<c0a6503c>] (kernel_init+0x8/0x10c) [<c0a6503c>] (kernel_init) from [<c01010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xee8c9fb0 to 0xee8c9ff8) ... ---[ end trace 4ed89cca1d70ea82 ]---
The above stack comes from Exynos5250 Arndale board (arch/arm/boot/dts/exynos5250-arndale.dts), where wm8994 codec tries to get regulator, which is provided by its parent mfd device. Similar issue can be observed on Exynos4412-based Trats2 and Exynos5433 TM2(e) boards.
It looks that some more checks have to be done before adding a link between regulator consumer and regulator driver, because it is not that uncommon that regulator consumer shares the parent device with regulator provider.
> --- > drivers/regulator/core.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c > index da9b0fed8330..bb1324f93143 100644 > --- a/drivers/regulator/core.c > +++ b/drivers/regulator/core.c > @@ -1740,6 +1740,8 @@ struct regulator *_regulator_get(struct device *dev, const char *id, > rdev->use_count = 0; > } > > + device_link_add(dev, &rdev->dev, DL_FLAG_STATELESS); > + > return regulator; > } > > @@ -1829,9 +1831,21 @@ static void _regulator_put(struct regulator *regulator) > > debugfs_remove_recursive(regulator->debugfs); > > - /* remove any sysfs entries */ > - if (regulator->dev) > + if (regulator->dev) { > + int count = 0; > + struct regulator *r; > + > + list_for_each_entry(r, &rdev->consumer_list, list) > + if (r->dev == regulator->dev) > + count++; > + > + if (count == 1) > + device_link_remove(regulator->dev, &rdev->dev); > + > + /* remove any sysfs entries */ > sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name); > + } > + > regulator_lock(rdev); > list_del(®ulator->list); >
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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