Re: [PATCH 1/1] net: phy: realtek: Add support for PHY LEDs on RTL8221B

[Nicolai Buchwitz <nb@tipi-net.de>]

On 1.4.2026 12:00, Chukun Pan wrote:
> Realtek RTL8221B Ethernet PHY supports three LED pins which are used to
> indicate link status and activity. Add netdev trigger support for them.
> 
> Signed-off-by: Chukun Pan <amadeus@jmu.edu.cn>
> ---
>  drivers/net/phy/realtek/realtek_main.c | 146 +++++++++++++++++++++++++
>  1 file changed, 146 insertions(+)
> 
> diff --git a/drivers/net/phy/realtek/realtek_main.c 
> b/drivers/net/phy/realtek/realtek_main.c
> index 023e47ad605b..8a22e18e5c56 100644
> --- a/drivers/net/phy/realtek/realtek_main.c
> +++ b/drivers/net/phy/realtek/realtek_main.c
> @@ -150,6 +150,15 @@
> 

[...]

> 
> +static int rtl822xb_led_brightness_set(struct phy_device *phydev, u8 
> index,
> +				       enum led_brightness value)
> +{
> +	int ret;
> +
> +	if (index >= RTL8211x_LED_COUNT)
> +		return -EINVAL;
> +
> +	/* clear HW LED setup */
> +	ret = phy_write_mmd(phydev, MDIO_MMD_VEND2,
> +			    RTL822X_VND2_LED(index), 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* clear HW LED blink */
> +	return phy_clear_bits_mmd(phydev, MDIO_MMD_VEND2,
> +				  RTL822X_VND2_LCR6,
> +				  RTL822X_VND2_LED_ACT(index));
> +}

This clears HW triggers but never actually turns the LED on when
value != LED_OFF. Both paths do the same thing: clear link and
activity config (value isn't used at all).

For LED_OFF that works (no triggers = LED off), but for LED_ON the
LED stays off too since there's no force-on written anywhere.

Compare with bcm_phy_led_brightness_set() which explicitly switches
between BCM_LED_SRC_ON and BCM_LED_SRC_OFF based on value.

If the RTL8221B has a software force-on register, it needs to be
programmed here. If it doesn't, brightness_set should not be
implemented at all. The framework handles its absence.

[...]

Thanks

Nicolai