Re: [PATCH 2/2] platform: arm64: Add HP OmniBook 5 16 embedded controller driver

[Konrad Dybcio]

On 11/9/26 11:49 AM, Rahul Pon wrote:
> The embedded controller of the HP OmniBook 5 16 (Snapdragon X2) sits on
> I2C at address 0x76 and takes commands through a mailbox: wait for an
> idle status (0xef), write the command and sub-command (0xed), wait for
> completion, then read the 32-byte reply (0xee). Its interrupt line
> signals events, read from register 0x00 and acknowledged by writing 0
> back, as HP's ACPI does.

[...]

> +What:		/sys/bus/i2c/devices/<bus>-0076/kbd_backlight_level
> +Date:		September 2026
> +KernelVersion:	7.4
> +Contact:	Rahul Pon <theflyingrahul@xxxxxxxxx>
> +Description:
> +		(RO) The keyboard backlight level of the HP OmniBook 5 16:
> +		0 (off), 1 or 2. Only the backlight key changes it, inside the
> +		embedded controller. The attribute is notified when the EC
> +		reports a change.

That's already reported in <led_subdevice_path>/brightness

[...]


> +static enum led_brightness hpec_led_get(struct led_classdev *cdev)
> +{
> +	struct hpec_led *led = container_of(cdev, struct hpec_led, cdev);
> +	u8 reply[HPEC_REPLY_LEN];
> +
> +	if (hpec_command(led->ec, HPEC_LED, HPEC_LED_GET, reply))
> +		return LED_OFF;
> +
> +	return (reply[1] >> (led->index - hpec_leds[0].index)) & 1;

"& 1" -> "& BIT(0)"

Konrad