[PATCH v4 1/4] Fixed PHY: Add fixed_phy_change_carrier()

[Joakim Tjernlund]

Drivers can use this as .ndo_change_carrier() to change carrier
via /sys/class/net/ethX/carrier.

Signed-off-by: Joakim Tjernlund <joakim.tjernl...@infinera.com>
---
 v4 - format fixes.

 v3 - Moved the logic into fixed PHY to minimize eth driver
      impact

 v2 - Only allow carrier changes for Fixed PHYs

 drivers/net/phy/fixed_phy.c | 24 +++++++++++++++++++++++-
 include/linux/phy_fixed.h   |  5 +++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
index 67b260877f30..37f732b5a532 100644
--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -25,6 +25,7 @@
 #include <linux/gpio.h>
 #include <linux/seqlock.h>
 #include <linux/idr.h>
+#include <linux/netdevice.h>
 
 #include "swphy.h"
 
@@ -38,6 +39,7 @@ struct fixed_phy {
        struct phy_device *phydev;
        seqcount_t seqcount;
        struct fixed_phy_status status;
+       bool no_carrier;
        int (*link_update)(struct net_device *, struct fixed_phy_status *);
        struct list_head node;
        int link_gpio;
@@ -48,9 +50,28 @@ static struct fixed_mdio_bus platform_fmb = {
        .phys = LIST_HEAD_INIT(platform_fmb.phys),
 };
 
+int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
+{
+       struct fixed_mdio_bus *fmb = &platform_fmb;
+       struct phy_device *phydev = dev->phydev;
+       struct fixed_phy *fp;
+
+       if (!phydev || !phydev->mdio.bus)
+               return -EINVAL;
+
+       list_for_each_entry(fp, &fmb->phys, node) {
+               if (fp->addr == phydev->mdio.addr) {
+                       fp->no_carrier = !new_carrier;
+                       return 0;
+               }
+       }
+       return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(fixed_phy_change_carrier);
+
 static void fixed_phy_update(struct fixed_phy *fp)
 {
-       if (gpio_is_valid(fp->link_gpio))
+       if (!fp->no_carrier && gpio_is_valid(fp->link_gpio))
                fp->status.link = !!gpio_get_value_cansleep(fp->link_gpio);
 }
 
@@ -66,6 +87,7 @@ static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, 
int reg_num)
 
                        do {
                                s = read_seqcount_begin(&fp->seqcount);
+                               fp->status.link = !fp->no_carrier;
                                /* Issue callback if user registered it. */
                                if (fp->link_update) {
                                        
fp->link_update(fp->phydev->attached_dev,
diff --git a/include/linux/phy_fixed.h b/include/linux/phy_fixed.h
index ee54453a40a0..9525567b1951 100644
--- a/include/linux/phy_fixed.h
+++ b/include/linux/phy_fixed.h
@@ -13,6 +13,7 @@ struct fixed_phy_status {
 struct device_node;
 
 #if IS_ENABLED(CONFIG_FIXED_PHY)
+extern int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier);
 extern int fixed_phy_add(unsigned int irq, int phy_id,
                         struct fixed_phy_status *status,
                         int link_gpio);
@@ -47,6 +48,10 @@ static inline int fixed_phy_set_link_update(struct 
phy_device *phydev,
 {
        return -ENODEV;
 }
+static inline int fixed_phy_change_carrier(struct net_device *dev, bool 
new_carrier)
+{
+       return -EINVAL;
+}
 #endif /* CONFIG_FIXED_PHY */
 
 #endif /* __PHY_FIXED_H */
-- 
2.18.1