[0/3] PWM framework: add support referencing PWMs from ACPI

Message

Nikolaus Voss May 29, 2019, 12:18 p.m. UTC

As described in Documentation/firmware-guide/acpi/gpio-properties.rst a
GPIO can be referenced from ACPI ASL _DSD with the "gpios"-property of the
form:

  Package () { "gpios", Package () { ref, index, pin, active_low }}

The second patch of this series adds support for specifing a PWM
reference in ASL of the form

  Package () { "pwms", Package () { ref, index, pwm-period [, pwm flags]}}

The first patch of this series is necessary to resolve the "ref" in ASL
if the table has been loaded by efivar_ssdt_load() or configfs.

The third patch of this series makes leds-pwm use the ACPI-enabled
PWM framework.

Nikolaus Voss (3):
  ACPI: Resolve objects on host-directed table loads
  PWM framework: add support referencing PWMs from ACPI
  leds-pwm.c: support ACPI via firmware-node framework

 drivers/acpi/acpi_configfs.c   |   6 +-
 drivers/acpi/acpica/tbxfload.c |  11 ++++
 drivers/leds/leds-pwm.c        |  44 +++++++------
 drivers/pwm/core.c             | 112 +++++++++++++++++++++++++++++++++
 include/linux/pwm.h            |   9 +++
 5 files changed, 159 insertions(+), 23 deletions(-)