[PATCH RFC leds + net-next 5/7] net: phy: add simple incrementing phyindex member to phy_device struct

[Marek Behún]

Add a new integer member phyindex to struct phy_device. This member is
unique for every phy_device. Atomic incrementation occurs in
phy_device_register.

This can be used for example in LED sysfs API. The LED subsystem names
each LED in format `device:color:function`, but currently the PHY device
names are not suited for this, since in some situations a PHY device
name can look like this
  d0032004.mdio-mii:01
or even like this
  !soc!internal-regs@d0000000!mdio@32004!switch0@10!mdio:08
Clearly this cannot be used as the `device` part of a LED name.

Signed-off-by: Marek Behún <ka...@kernel.org>
---
 drivers/net/phy/phy_device.c | 3 +++
 include/linux/phy.h          | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 5dab6be6fc38..38f581cc9713 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -9,6 +9,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/atomic.h>
 #include <linux/bitmap.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
@@ -892,6 +893,7 @@ EXPORT_SYMBOL(get_phy_device);
  */
 int phy_device_register(struct phy_device *phydev)
 {
+       static atomic_t phyindex;
        int err;
 
        err = mdiobus_register_device(&phydev->mdio);
@@ -908,6 +910,7 @@ int phy_device_register(struct phy_device *phydev)
                goto out;
        }
 
+       phydev->phyindex = atomic_inc_return(&phyindex) - 1;
        err = device_add(&phydev->mdio.dev);
        if (err) {
                phydev_err(phydev, "failed to add\n");
diff --git a/include/linux/phy.h b/include/linux/phy.h
index eb3cb1a98b45..6dd4a28135c3 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -480,6 +480,7 @@ struct macsec_ops;
  *
  * @mdio: MDIO bus this PHY is on
  * @drv: Pointer to the driver for this PHY instance
+ * @phyindex: a simple incrementing PHY index
  * @phy_id: UID for this device found during discovery
  * @c45_ids: 802.3-c45 Device Identifiers if is_c45.
  * @is_c45:  Set to true if this PHY uses clause 45 addressing.
@@ -551,6 +552,8 @@ struct phy_device {
        /* And management functions */
        struct phy_driver *drv;
 
+       int phyindex;
+
        u32 phy_id;
 
        struct phy_c45_device_ids c45_ids;
-- 
2.26.2