Messages in this thread | | | From | Martin Fuzzey <> | Subject | Regulator: drivers that need to know their supply | Date | Thu, 7 Apr 2016 15:25:09 +0200 |
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Hi,
I am working on a driver for the tps22993 load switch.
This chip has configurable slew rates but no voltage setting (as it's just a switch).
To implement the .enable_time() method I need the voltage (which is the supply's voltage).
The problem is that, when my regulator is configured as always-on the supply is not known when .enable_time() is called from regulator_register() (it does work if the regulator is not always-on)
This is similar to the problem fixed by 5e3ca2b349b1 regulator: Try to resolve regulators supplies on registration and the follow up deadlock fix.
I tried adding a new function:
struct regulator *rdev_get_supply(struct regulator_dev *rdev) { int rc;
rc = regulator_resolve_supply(rdev); if (rc) return ERR_PTR(rc); return rdev->supply; } EXPORT_SYMBOL_GPL(rdev_get_supply);
Unfortunately that doesn't work. First of all supply_name is not set at that point (since it is set in regulator_register() AFTER set_machine_constraints())
Even after swapping the call order in regulator_register() it still doesn't work for my configuration since the parent supply is probed later so rdev_get_supply() returns -EDEFER which just results in a warning message from _regulator_do_enable() when it propagates back from .enable_time()
3V3_LCD: enable_time() failed: -517
And even without that problem there is a risk of another deadlock since the driver callbacks are called from regulator_register() with the regulator_list mutex held in the always_on case.
Any ideas how to do this?
Regards,
Martin
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