netdev - Re: [PATCH net-next v1 1/2] net: phy: Add support for driver-specific next update time

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Message-ID: <0f42a6ef-9d7a-4dfa-909f-36578a027320@intel.com>
Date: Tue, 4 Feb 2025 12:50:36 +0100
From: Mateusz Polchlopek <mateusz.polchlopek@...el.com>
To: Oleksij Rempel <o.rempel@...gutronix.de>, Andrew Lunn <andrew@...n.ch>,
	Heiner Kallweit <hkallweit1@...il.com>, Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
CC: <kernel@...gutronix.de>, <linux-kernel@...r.kernel.org>,
	<netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v1 1/2] net: phy: Add support for driver-specific
 next update time



On 2/4/2025 10:32 AM, Oleksij Rempel wrote:
> Introduce the `phy_get_next_update_time` function to allow PHY drivers
> to dynamically determine the time (in milliseconds) until the next state
> update event. This enables more flexible and adaptive polling intervals
> based on the link state or other conditions.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> ---
>   drivers/net/phy/phy.c | 28 ++++++++++++++++++++++++++--
>   include/linux/phy.h   | 13 +++++++++++++
>   2 files changed, 39 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index d0c1718e2b16..77ed7bfdf200 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -1501,6 +1501,25 @@ void phy_free_interrupt(struct phy_device *phydev)
>   }
>   EXPORT_SYMBOL(phy_free_interrupt);
>   
> +/**
> + * phy_get_next_update_time - Determine the next PHY update time
> + * @phydev: Pointer to the phy_device structure
> + *
> + * This function queries the PHY driver to get the time for the next polling
> + * event. If the driver does not implement the callback, a default value is used.
> + *
> + * Return: The time for the next polling event in milliseconds
> + */
> +static unsigned int phy_get_next_update_time(struct phy_device *phydev)
> +{
> +	const unsigned int default_time = PHY_STATE_TIME;

Why you create this variable? It is used only in return, so I would
rather just simplify by doing:

return PHY_STATE_TIME;

> +
> +	if (phydev->drv && phydev->drv->get_next_update_time)
> +		return phydev->drv->get_next_update_time(phydev);
> +
> +	return default_time;
> +}
> +
>   enum phy_state_work {
>   	PHY_STATE_WORK_NONE,
>   	PHY_STATE_WORK_ANEG,
> @@ -1579,8 +1598,13 @@ static enum phy_state_work _phy_state_machine(struct phy_device *phydev)
>   	 * state machine would be pointless and possibly error prone when
>   	 * called from phy_disconnect() synchronously.
>   	 */
> -	if (phy_polling_mode(phydev) && phy_is_started(phydev))
> -		phy_queue_state_machine(phydev, PHY_STATE_TIME);
> +	if (phy_polling_mode(phydev) && phy_is_started(phydev)) {
> +		unsigned int next_update_time =
> +			phy_get_next_update_time(phydev);
> +
> +		phy_queue_state_machine(phydev,
> +					msecs_to_jiffies(next_update_time));
> +	}
>   
>   	return state_work;
>   }
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 19f076a71f94..d5cf979f4a6b 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -1273,6 +1273,19 @@ struct phy_driver {
>   	 */
>   	int (*led_polarity_set)(struct phy_device *dev, int index,
>   				unsigned long modes);
> +
> +	/**
> +	 * @get_next_update_time: Get the time until the next update event
> +	 * @dev: PHY device which has the LED
> +	 *
> +	 * Callback to determine the time (in milliseconds) until the next
> +	 * update event for the PHY state  machine. Allows PHY drivers to
> +	 * dynamically adjust polling intervals based on link state or other
> +	 * conditions.
> +	 *
> +	 * Returns the time in milliseconds until the next update event.
> +	 */
> +	unsigned int (*get_next_update_time)(struct phy_device *dev);
>   };
>   #define to_phy_driver(d) container_of_const(to_mdio_common_driver(d),		\
>   				      struct phy_driver, mdiodrv)