Re: [PATCH v1] net: phy: airoha: add AN8811HB MCU assert/deassert support

[Andrew Lunn]

On Sun, Mar 15, 2026 at 09:41:55PM +0800, Lucien.Jheng wrote:
> AN8811HB requires the MCU to be held in reset before firmware
> loading and released afterwards via a dedicated PBUS register
> pair (0x5cf9f8 / 0x5cf9fc), accessed through the PHY-addr+8
> MDIO bus node rather than the BUCKPBUS indirect path.
> 
> Add __air_pbus_reg_write() as a low-level helper for this
> access, then implement an8811hb_mcu_assert() / _deassert()
> on top of it.  Wire both into an8811hb_load_firmware() and
> en8811h_restart_mcu() so every firmware load or MCU restart
> on AN8811HB correctly sequences the reset control registers.

What happens if the MCU is not held in reset? Should this be
considered a fix?

What are the valid PHY addresses for this device? Do we need to worry
about the PHY is at address 31, is the dedicated PBUS register is at
7?

> +static int an8811hb_mcu_assert(struct phy_device *phydev)
> +{
> +	int ret;
> +
> +	phy_lock_mdio_bus(phydev);
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_RST,
> +				   AN8811HB_MCU_SW_RST_HOLD);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	ret = __air_pbus_reg_write(phydev, AN8811HB_MCU_SW_START, 0);
> +	if (ret < 0)
> +		goto unlock;
> +
> +	msleep(50);
> +	phydev_info(phydev, "MCU asserted\n");

Please don't spam the log. phydev_dbg() or not at all.

>  static int an8811hb_load_firmware(struct phy_device *phydev)
>  {
>  	int ret;
>  
> +	ret = an8811hb_mcu_assert(phydev);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = an8811hb_mcu_deassert(phydev);
> +	if (ret < 0)
> +		return ret;
> +

Assert and then deassert, but no firmware download between? That is
not what the commit message says.

	Andrew