Messages in this thread Patch in this message | | | Date | Tue, 16 Jun 2020 08:58:34 +0100 | From | Lee Jones <> | Subject | Re: [PATCH v2 1/2] mfd: mfd-core: Add mechanism for removal of a subset of children |
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On Mon, 15 Jun 2020, Charles Keepax wrote:
> Currently, the only way to remove MFD children is with a call to > mfd_remove_devices, which will remove all the children. Under > some circumstances it is useful to remove only a subset of the > child devices. For example if some additional clean up is required > between removal of certain child devices. > > To accomplish this a tag field is added to mfd_cell, and a > corresponding mfd_remove_devices_by_tag function is added to > remove children with a specific tag. This allows a good amount of > flexibility in which child devices a driver wishes to remove, as a > driver could target specific drivers or a large group. Allowing other > use-cases such as removing drivers for functionality that is no longer > required. > > Some investigation was done of using the mfd_cell name and id fields, > but it is hard to achieve a good level of flexibility there, at least > without significant complexity. Since the id gets modified by the core > and can even by automatically generated. Using the name alone would > work for my usecase but it is not hard to imagine a situation where it > wouldn't. > > Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> > --- > > Following on from our discussions here: │·················· > │·················· > https://lore.kernel.org/lkml/20200122110842.10702-2-ckeepax@opensource.cirrus.com/#t │·················· > │·················· > Happy to discuss other approaches as well, but this one was quite │·················· > appealing as it was very simple but affords quite a lot of flexibility. │··················
What about this?
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index f5a73af60dd40..a06e0332e1e31 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -283,7 +283,7 @@ int mfd_add_devices(struct device *parent, int id, } EXPORT_SYMBOL(mfd_add_devices); -static int mfd_remove_devices_fn(struct device *dev, void *data) +static int mfd_remove_devices_fn(struct device *dev, void *level) { struct platform_device *pdev; const struct mfd_cell *cell; @@ -294,6 +294,9 @@ static int mfd_remove_devices_fn(struct device *dev, void *data) pdev = to_platform_device(dev); cell = mfd_get_cell(pdev); + if (cell->level && (!level || cell->level != *level)) + return 0; + regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies, cell->num_parent_supplies); @@ -303,7 +306,11 @@ static int mfd_remove_devices_fn(struct device *dev, void *data) void mfd_remove_devices(struct device *parent) { + int level = MFD_DEP_LEVEL_HIGH; + device_for_each_child_reverse(parent, NULL, mfd_remove_devices_fn); + device_for_each_child_reverse(parent, &level, mfd_remove_devices_fn); } EXPORT_SYMBOL(mfd_remove_devices);
No need for special calls from the parent driver in this case. Just a requirement to set the cell's dependency level.
-- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
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