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driver/intel/mipi_camera: Add support for _DSC field 

The _DSC (Device State for Configuration) object evaluates to an integer
may be used to tell Linux the highest allowed D state for a device
during probe. The support for _DSC requires support from the kernel
bus type if the bus driver normally sets the device in D0 state for
probe.

The D states and thus also the allowed values for _DSC are listed below.
Number	State	Description
0	D0	Device fully powered on
1	D1
2	D2
3	D3hot
4	D3cold	Off

More details can be found here https://lkml.org/lkml/2021/10/25/397

BUG=none
BRANCH=none
TEST=Add corresponding field in brya, boot and dump SSDT to check if
_DSC field is as per expectation.

            Name (_ADR, Zero)  // _ADR: Address
            Name (_HID, "OVTI8856")  // _HID: Hardware ID
            Name (_UID, Zero)  // _UID: Unique ID
            Name (_DDN, "Ov 8856 Camera")  // _DDN: DOS Device Name
            Method (_STA, 0, NotSerialized)  // _STA: Status
            {
                Return (0x0F)
            }

            Method (_DSC, 0, NotSerialized)
            {
                Return (0x04)
            }

Signed-off-by: Varshit B Pandya <varshit.b.pandya@intel.com>
Change-Id: I5471f144918413a2982f86beaf3dbf7e4e66cc9b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58767
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Maulik V Vaghela <maulik.v.vaghela@intel.com>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
This commit is contained in:
Varshit B Pandya 2021-10-27 10:41:32 +05:30 committed by Felix Held
parent 423e9e0fc0
commit 04e8c2b5ff
2 changed files with 14 additions and 0 deletions
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3
src/drivers/intel/mipi_camera/camera.c
View File

@ -847,6 +847,9 @@ static void write_i2c_camera_device(const struct device *dev, const char *scope)
acpigen_write_name_integer("_UID", config->acpi_uid);
acpigen_write_name_string("_DDN", config->chip_name);
acpigen_write_STA(acpi_device_status(dev));
acpigen_write_method("_DSC", 0);
acpigen_write_return_integer(config->max_dstate_for_probe);
acpigen_pop_len(); /* Method _DSC */
/* Resources */
acpigen_write_name("_CRS");

11
src/drivers/intel/mipi_camera/chip.h
View File

@ -257,6 +257,17 @@ struct drivers_intel_mipi_camera_config {
bool has_power_resource;
/* Perform low power probe */
bool low_power_probe;
/*
* This will create a _DSC method in ACPI which returns an integer, to tell the kernel
* the highest allowed D state for a device during probe
* Number State Description
* 0 D0 Device fully powered on
* 1 D1
* 2 D2
* 3 D3hot
* 4 D3cold Off
*/
uint8_t max_dstate_for_probe;
};
#endif