Re: [net-next PATCH v3 04/14] net: phy: Add a binding for PHY LEDs

[Vladimir Oltean <olteanv@gmail.com>]

On Tue, Mar 14, 2023 at 11:15:06AM +0100, Christian Marangi wrote:
> From: Andrew Lunn <andrew@lunn.ch>
> 
> Define common binding parsing for all PHY drivers with LEDs using
> phylib. Parse the DT as part of the phy_probe and add LEDs to the
> linux LED class infrastructure. For the moment, provide a dummy
> brightness function, which will later be replaced with a call into the
> PHY driver.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/net/phy/phy_device.c | 89 ++++++++++++++++++++++++++++++++++++
>  include/linux/phy.h          | 16 +++++++
>  2 files changed, 105 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 9ba8f973f26f..8acade42615c 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -19,10 +19,12 @@
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
> +#include <linux/list.h>
>  #include <linux/mdio.h>
>  #include <linux/mii.h>
>  #include <linux/mm.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
>  #include <linux/netdevice.h>
>  #include <linux/phy.h>
>  #include <linux/phy_led_triggers.h>
> @@ -658,6 +660,7 @@ struct phy_device *phy_device_create(struct mii_bus *bus, int addr, u32 phy_id,
>  	device_initialize(&mdiodev->dev);
>  
>  	dev->state = PHY_DOWN;
> +	INIT_LIST_HEAD(&dev->led_list);
>  
>  	mutex_init(&dev->lock);
>  	INIT_DELAYED_WORK(&dev->state_queue, phy_state_machine);
> @@ -2964,6 +2967,85 @@ static bool phy_drv_supports_irq(struct phy_driver *phydrv)
>  	return phydrv->config_intr && phydrv->handle_interrupt;
>  }
>  
> +/* Dummy implementation until calls into PHY driver are added */
> +static int phy_led_set_brightness(struct led_classdev *led_cdev,
> +				  enum led_brightness value)
> +{
> +	return 0;
> +}
> +
> +static int of_phy_led(struct phy_device *phydev,
> +		      struct device_node *led)
> +{
> +	struct device *dev = &phydev->mdio.dev;
> +	struct led_init_data init_data = {};
> +	struct led_classdev *cdev;
> +	struct phy_led *phyled;
> +	int err;
> +
> +	phyled = devm_kzalloc(dev, sizeof(*phyled), GFP_KERNEL);
> +	if (!phyled)
> +		return -ENOMEM;
> +
> +	phyled->phydev = phydev;

hmm.. not used in this patch

> +	cdev = &phyled->led_cdev;
> +	INIT_LIST_HEAD(&phyled->led_list);

I believe list elements don't need INIT_LIST_HEAD(), only the head
(phydev->led_list) does?

> +
> +	err = of_property_read_u32(led, "reg", &phyled->index);
> +	if (err)
> +		return err;
> +
> +	cdev->brightness_set_blocking = phy_led_set_brightness;
> +	cdev->max_brightness = 1;
> +	init_data.devicename = dev_name(&phydev->mdio.dev);
> +	init_data.fwnode = of_fwnode_handle(led);
> +
> +	err = devm_led_classdev_register_ext(dev, cdev, &init_data);
> +	if (err)
> +		return err;
> +
> +	list_add(&phyled->led_list, &phydev->led_list);
> +
> +	return 0;
> +}
> +
> +static int of_phy_leds(struct phy_device *phydev)
> +{
> +	struct device_node *node = phydev->mdio.dev.of_node;
> +	struct device_node *leds, *led;
> +	int err;
> +
> +	if (!IS_ENABLED(CONFIG_OF_MDIO))
> +		return 0;
> +
> +	if (!node)
> +		return 0;
> +
> +	leds = of_get_child_by_name(node, "leds");
> +	if (!leds)
> +		return 0;
> +
> +	for_each_available_child_of_node(leds, led) {
> +		err = of_phy_led(phydev, led);
> +		if (err)
> +			return err;

Agree with you that devres allows you to write yolo error teardown
code.. but of_node_put() after of_get_child_by_name()?

> +	}
> +
> +	return 0;
> +}
> +
> +static void phy_leds_remove(struct phy_device *phydev)
> +{
> +	struct device *dev = &phydev->mdio.dev;
> +	struct led_classdev *cdev;
> +	struct phy_led *phyled;
> +
> +	list_for_each_entry(phyled, &phydev->led_list, led_list) {
> +		cdev = &phyled->led_cdev;
> +		devm_led_classdev_unregister(dev, cdev);

is this really needed? shouldn't devres unregister the led classdev
after phy_remove() ends, anyway?

> +	}
> +}
> +
>  /**
>   * fwnode_mdio_find_device - Given a fwnode, find the mdio_device
>   * @fwnode: pointer to the mdio_device's fwnode
> @@ -3142,6 +3224,11 @@ static int phy_probe(struct device *dev)
>  	/* Set the state to READY by default */
>  	phydev->state = PHY_READY;
>  
> +	/* Get the LEDs from the device tree, and instantiate standard
> +	 * LEDs for them.
> +	 */
> +	of_phy_leds(phydev);

It would probably be good to treat the error code here, to not create a
precedent where invalid bindings (no "reg" for example) were accepted?

> +
>  out:
>  	/* Assert the reset signal */
>  	if (err)
> @@ -3156,6 +3243,8 @@ static int phy_remove(struct device *dev)
>  {
>  	struct phy_device *phydev = to_phy_device(dev);
>  
> +	phy_leds_remove(phydev);
> +
>  	cancel_delayed_work_sync(&phydev->state_queue);
>  
>  	mutex_lock(&phydev->lock);
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index fbeba4fee8d4..1b1efe120f0f 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -14,6 +14,7 @@
>  #include <linux/compiler.h>
>  #include <linux/spinlock.h>
>  #include <linux/ethtool.h>
> +#include <linux/leds.h>
>  #include <linux/linkmode.h>
>  #include <linux/netlink.h>
>  #include <linux/mdio.h>
> @@ -595,6 +596,7 @@ struct macsec_ops;
>   * @phy_num_led_triggers: Number of triggers in @phy_led_triggers
>   * @led_link_trigger: LED trigger for link up/down
>   * @last_triggered: last LED trigger for link speed
> + * @led_list: list of PHY LED structures
>   * @master_slave_set: User requested master/slave configuration
>   * @master_slave_get: Current master/slave advertisement
>   * @master_slave_state: Current master/slave configuration
> @@ -690,6 +692,7 @@ struct phy_device {
>  
>  	struct phy_led_trigger *led_link_trigger;
>  #endif
> +	struct list_head led_list;
>  
>  	/*
>  	 * Interrupt number for this PHY
> @@ -825,6 +828,19 @@ struct phy_plca_status {
>  	bool pst;
>  };
>  
> +/* phy_led: An LED driven by the PHY
> + *
> + * phydev: Pointer to the PHY this LED belongs to
> + * led_cdev: Standard LED class structure
> + * index: Number of the LED

led_list not described in comments

Also, does this deliberately not use the kerneldoc style /**?

Also, small nitpick, feel free to ignore it. Since it's unlikely that a
phy_led would be chained onto more than one list, I guess its "led_list"
field could be simply named "list", leaving "led_list" only to struct phy_device?

> + */
> +struct phy_led {
> +	struct list_head led_list;
> +	struct phy_device *phydev;
> +	struct led_classdev led_cdev;
> +	u32 index;
> +};
> +
>  /**
>   * struct phy_driver - Driver structure for a particular PHY type
>   *
> -- 
> 2.39.2
> 

no "depends on LEDS_CLASS" in the Kconfig?