On Mon, 27 Jan 2014 00:32:14 +0000, Mark Brown wrote: > From: Mark Brown <broonie@xxxxxxxxxx> > > There is currently no facility in ACPI to express the hookup of voltage > regulators, the expectation is that the regulators that exist in the > system will be handled transparently by firmware if they need software > control at all. This means that if for some reason the regulator API is > enabled on such a system it should assume that any supplies that devices > need are provided by the system at all relevant times without any software > intervention. > > Tell the regulator core to make this assumption by calling > regulator_has_full_constraints(). Do this as soon as we know we are using > ACPI so that the information is available to the regulator core as early > as possible. This will cause the regulator core to pretend that there is > an always on regulator supplying any supply that is requested but that has > not otherwise been mapped which is the behaviour expected on a system with > ACPI. > > Should the ability to specify regulators be added in future revisions of > ACPI then once we have support for ACPI mappings in the kernel the same > assumptions will apply. It is also likely that systems will default to a > mode of operation which does not require any interpretation of these > mappings in order to be compatible with existing operating system releases > so it should remain safe to make these assumptions even if the mappings > exist but are not supported by the kernel. > > Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> > --- > drivers/acpi/bus.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c > index 384da5ab5955..fcb59c21c68d 100644 > --- a/drivers/acpi/bus.c > +++ b/drivers/acpi/bus.c > @@ -33,6 +33,7 @@ > #include <linux/proc_fs.h> > #include <linux/acpi.h> > #include <linux/slab.h> > +#include <linux/regulator/machine.h> > #ifdef CONFIG_X86 > #include <asm/mpspec.h> > #endif > @@ -509,6 +510,14 @@ void __init acpi_early_init(void) > goto error0; > } > > + /* > + * If the system is using ACPI then we can be reasonably > + * confident that any regulators are managed by the firmware > + * so tell the regulator core it has everything it needs to > + * know. > + */ > + regulator_has_full_constraints(); > + > return; > > error0: I think it makes sense to have this included in stable kernel trees? Thanks, -- Jean Delvare -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
