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[v2,0/2] leds: trigger: netdev: add additional modes

Message ID 20230610041616.21141-1-ansuelsmth@gmail.com
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Series leds: trigger: netdev: add additional modes | expand

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Christian Marangi June 10, 2023, 4:16 a.m. UTC 
This is a continue of [1]. It was decided to take a more gradual
approach to implement LEDs support for switch and phy starting with
basic support and then implementing the hw control part when we have all
the prereq done.

This should be the final part for the netdev trigger.

We collect some info around and we found a good set of modes that are
common in almost all the PHY and Switch.

These modes are:
- Modes for dedicated link speed(10, 100, 1000 mbps). Additional mode
  can be added later following this example.
- Modes for half and full duplex.

The original idea was to add hw control only modes.
While the concept makes sense in practice it would results in lots of 
additional code and extra check to make sure we are setting correct modes.

With the suggestion from Andrew it was pointed out that using the ethtool
APIs we can actually get the current link speed and duplex and this
effectively removed the problem of having hw control only modes since we
can fallback to software.

Since these modes are supported by software, we can skip providing an
user for this in the LED driver to support hw control for these new modes
(that will come right after this is merged) and prevent this to be another
multi subsystem series.

For link speed and duplex we use ethtool APIs.

To call ethtool APIs, rtnl lock is needed but this can be skipped on
handling netdev events as the lock is already held.

[1] https://lore.kernel.org/lkml/20230216013230.22978-1-ansuelsmth@gmail.com/

Changes v2:
- Drop ACTIVITY patch as it can be handled internally in the LED driver
- Reduce duplicate code and move the link state to a dedicated helper

Christian Marangi (2):
  leds: trigger: netdev: add additional specific link speed mode
  leds: trigger: netdev: add additional specific link duplex mode

 drivers/leds/trigger/ledtrig-netdev.c | 103 +++++++++++++++++++++++---
 include/linux/leds.h                  |   5 ++
 2 files changed, 98 insertions(+), 10 deletions(-)

Comments

Andrew Lunn June 11, 2023, 3:57 p.m. UTC | #1 
On Sat, Jun 10, 2023 at 06:16:15AM +0200, Christian Marangi wrote:
> Add additional modes for specific link speed. Use ethtool APIs to get the
> current link speed and enable the LED accordingly. Under netdev event
> handler the rtnl lock is already held and is not needed to be set to
> access ethtool APIs.
> 
> This is especially useful for PHY and Switch that supports LEDs hw
> control for specific link speed. (example scenario a PHY that have 2 LED
> connected one green and one orange where the green is turned on with
> 1000mbps speed and orange is turned on with 10mpbs speed)
> 
> On mode set from sysfs we check if we have enabled split link speed mode
> and reject enabling generic link mode to prevent wrong and redundant
> configuration.
> 
> Rework logic on the set baseline state to support these new modes to
> select if we need to turn on or off the LED.
> 
> Add additional modes:
> - link_10: Turn on LED when link speed is 10mbps
> - link_100: Turn on LED when link speed is 100mbps
> - link_1000: Turn on LED when link speed is 1000mbps
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew