Messages in this thread Patch in this message | | | Subject | Re: [PATCH v2 2/2] regulator: add QCOM RPMh regulator driver | From | David Collins <> | Date | Wed, 25 Apr 2018 14:04:56 -0700 |
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>>> I think that's probably only OK if we have a specific error code for the >>> regulator being limited in this way otherwise our error handling for I/O >>> problems involves us trying to reconfigure supplies which seems like it >>> would be risky.
>> Would you be ok with -EAGAIN being used for this purpose?
> Using -EAGAIN for "I can't ever read the configuration from this > regulator" doesn't seem right - it's not like any number of retries > will ever manage to read the value back.
In this case, the _regulator_get_voltage() call can succeed, but only after a voltage is explicitly requested from the framework side. The intention here would then be to call _regulator_do_set_voltage() with the constraint min_uV to max_uV range. After that, subsequent _regulator_get_voltage() calls will be successful.
Here is the general idea:
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 65f9b7c..e61983d 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -910,6 +910,19 @@ static int machine_constraints_voltage(struct regulator_dev *rdev, rdev->constraints->min_uV && rdev->constraints->max_uV) { int target_min, target_max; int current_uV = _regulator_get_voltage(rdev); + if (current_uV == -EAGAIN) { + /* + * Regulator voltage cannot be read until after + * configuration; try setting constraint range. + */ + rdev_info(rdev, "Setting %d-%duV\n", + rdev->constraints->min_uV, + rdev->constraints->max_uV); + _regulator_do_set_voltage(rdev, + rdev->constraints->min_uV, + rdev->constraints->max_uV); + current_uV = _regulator_get_voltage(rdev); + } if (current_uV < 0) { rdev_err(rdev, "failed to get the current voltage(%d)\n", Do you still have reservations about using -EAGAIN for this purpose? If so, which error code would you suggest using?
Thanks, David
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