Introduction

This plugin updates the firmware of HDMI level shifter and protocol converter (LSPCON) devices made by Parade Technologies, such as the PS175.

These devices communicate over I²C, via either the DisplayPort aux channel or a dedicated bus- this plugin uses a dedicated bus declared by system firmware for, flashing, and reads the device firmware version from DPCD. Quirks specify the DisplayPort bus over which DPCD is read for a given system.

Firmware is stored on an external flash attached to an SPI bus on the device. The attached flash is assumed to be compatible with the W25Q20 series of devices, in particular supporting a 64k Block Erase command (0xD8) with 24-bit address and Write Enable for Volatile Status Register (0x05).

Firmware Format

The device firmware is in an unspecified binary format that is written directly to an inactive partition of the Flash attached to the device.

This plugin supports the following protocol ID:

• com.paradetech.ps176

GUID Generation

Devices use an extra instance ID derived from SMBIOS, e.g.

• I2C\NAME_1AF80175:00:00&FAMILY_Google_Hatch

Quirk Use

This plugin uses the following plugin-specific quirks:

ParadeLspconAuxDeviceName

The sysfs name of the drm_dp_aux_dev over which device version should be read.

Since: 1.6.2

Vendor ID security

The vendor ID is specified by system firmware (such as ACPI tables) and is part of the device’s name as read from sysfs.

External Interface Access

This plugin requires access to the DisplayPort aux channel to read DPCD, such as /dev/drm_dp_aux0 as well as the i2c bus attached to the device, such as /dev/i2c-7.