From 04e8c2b5ff85e246d6f711f58cc54b0e2ba91841 Mon Sep 17 00:00:00 2001 From: Varshit B Pandya Date: Wed, 27 Oct 2021 10:41:32 +0530 Subject: [PATCH] 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 Change-Id: I5471f144918413a2982f86beaf3dbf7e4e66cc9b Reviewed-on: https://review.coreboot.org/c/coreboot/+/58767 Tested-by: build bot (Jenkins) Reviewed-by: Maulik V Vaghela Reviewed-by: Subrata Banik Reviewed-by: Tim Wawrzynczak Reviewed-by: Felix Held --- src/drivers/intel/mipi_camera/camera.c | 3 +++ src/drivers/intel/mipi_camera/chip.h | 11 +++++++++++ 2 files changed, 14 insertions(+) diff --git a/src/drivers/intel/mipi_camera/camera.c b/src/drivers/intel/mipi_camera/camera.c index ec79e39a60..a9af25cf12 100644 --- a/src/drivers/intel/mipi_camera/camera.c +++ b/src/drivers/intel/mipi_camera/camera.c @@ -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"); diff --git a/src/drivers/intel/mipi_camera/chip.h b/src/drivers/intel/mipi_camera/chip.h index c6ead1ffd6..55e9f33fb1 100644 --- a/src/drivers/intel/mipi_camera/chip.h +++ b/src/drivers/intel/mipi_camera/chip.h @@ -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