linux-kernel - Re: [net-next,PATCH] net: phy: realtek: Add support for PHY LEDs on RTL8211F

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Date: Tue, 25 Jun 2024 03:59:06 +0200
From: Marek Vasut <marex@...x.de>
To: Daniel Golle <daniel@...rotopia.org>
Cc: netdev@...r.kernel.org, Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Andrew Lunn <andrew@...n.ch>,
 Christophe Roullier <christophe.roullier@...s.st.com>,
 "David S . Miller" <davem@...emloft.net>, Eric Dumazet
 <edumazet@...gle.com>, Heiner Kallweit <hkallweit1@...il.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 Russell King <linux@...linux.org.uk>, kernel@...electronics.com,
 linux-kernel@...r.kernel.org
Subject: Re: [net-next,PATCH] net: phy: realtek: Add support for PHY LEDs on
 RTL8211F

On 6/24/24 3:01 AM, Daniel Golle wrote:
> On Mon, Jun 24, 2024 at 01:40:33AM +0200, Marek Vasut wrote:
>> Realtek RTL8211F Ethernet PHY supports 3 LED pins which are used to
>> indicate link status and activity. Add minimal LED controller driver
>> supporting the most common uses with the 'netdev' trigger.
>>
>> Signed-off-by: Marek Vasut <marex@...x.de>
> 
>> [...]
>> +static int rtl8211f_led_hw_is_supported(struct phy_device *phydev, u8 index,
>> +					unsigned long rules)
>> +{
>> +	const unsigned long mask = BIT(TRIGGER_NETDEV_LINK_10) |
>> +				   BIT(TRIGGER_NETDEV_LINK_100) |
>> +				   BIT(TRIGGER_NETDEV_LINK_1000) |
>> +				   BIT(TRIGGER_NETDEV_RX) |
>> +				   BIT(TRIGGER_NETDEV_TX);
>> +
>> +	/* The RTL8211F PHY supports these LED settings on up to three LEDs:
>> +	 * - Link: Configurable subset of 10/100/1000 link rates
>> +	 * - Active: Blink on activity, RX or TX is not differentiated
>> +	 * The Active option has two modes, A and B:
>> +	 * - A: Link and Active indication at configurable, but matching,
>> +	 *      subset of 10/100/1000 link rates
>> +	 * - B: Link indication at configurable subset of 10/100/1000 link
>> +	 *      rates and Active indication always at all three 10+100+1000
>> +	 *      link rates.
>> +	 * This code currently uses mode B only.
>> +	 */
>> +
>> +	if (index >= RTL8211F_LED_COUNT)
>> +		return -EINVAL;
>> +
>> +	/* Filter out any other unsupported triggers. */
>> +	if (rules & ~mask)
>> +		return -EOPNOTSUPP;
> 
> It looks like it is not possible to let the hardware indicate only either
> RX or TX, it will always have to go together.
> 
> Please express this in this function accordingly, so fallback to
> software-driven trigger works as expected.
> 
> Example:
> if (!(rules & BIT(TRIGGER_NETDEV_RX)) ^ !(rules & BIT(TRIGGER_NETDEV_TX)))
> 	return -EOPNOTSUPP;

Added to V2, thank you.