net: phy: extend PHY package API to support multiple global address

Current API for PHY package are limited to single address to configure
global settings for the PHY package.

It was found that some PHY package (for example the qca807x, a PHY
package that is shipped with a bundle of 5 PHY) requires multiple PHY
address to configure global settings. An example scenario is a PHY that
have a dedicated PHY for PSGMII/serdes calibrarion and have a specific
PHY in the package where the global PHY mode is set and affects every
other PHY in the package.

Change the API in the following way:
- Change phy_package_join() to take the base addr of the PHY package
  instead of the global PHY addr.
- Make __/phy_package_write/read() require an additional arg that
  select what global PHY address to use by passing the offset from the
  base addr passed on phy_package_join().

Each user of this API is updated to follow this new implementation
following a pattern where an enum is defined to declare the offset of the
addr.

We also drop the check if shared is defined as any user of the
phy_package_read/write is expected to use phy_package_join first. Misuse
of this will correctly trigger a kernel panic for NULL pointer
exception.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 16 deletions

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index d8e9335d415c..0c52a9eff188 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1651,20 +1651,22 @@ EXPORT_SYMBOL_GPL(phy_driver_is_genphy_10g);
 /**
  * phy_package_join - join a common PHY group
  * @phydev: target phy_device struct
- * @addr: cookie and PHY address for global register access
+ * @base_addr: cookie and base PHY address of PHY package for offset
+ *   calculation of global register access
  * @priv_size: if non-zero allocate this amount of bytes for private data
  *
  * This joins a PHY group and provides a shared storage for all phydevs in
  * this group. This is intended to be used for packages which contain
  * more than one PHY, for example a quad PHY transceiver.
  *
- * The addr parameter serves as a cookie which has to have the same value
- * for all members of one group and as a PHY address to access generic
- * registers of a PHY package. Usually, one of the PHY addresses of the
- * different PHYs in the package provides access to these global registers.
+ * The base_addr parameter serves as cookie which has to have the same values
+ * for all members of one group and as the base PHY address of the PHY package
+ * for offset calculation to access generic registers of a PHY package.
+ * Usually, one of the PHY addresses of the different PHYs in the package
+ * provides access to these global registers.
  * The address which is given here, will be used in the phy_package_read()
- * and phy_package_write() convenience functions. If your PHY doesn't have
- * global registers you can just pick any of the PHY addresses.
+ * and phy_package_write() convenience functions as base and added to the
+ * passed offset in those functions.
  *
  * This will set the shared pointer of the phydev to the shared storage.
  * If this is the first call for a this cookie the shared storage will be
@@ -1674,17 +1676,17 @@ EXPORT_SYMBOL_GPL(phy_driver_is_genphy_10g);
  * Returns < 1 on error, 0 on success. Esp. calling phy_package_join()
  * with the same cookie but a different priv_size is an error.
  */
-int phy_package_join(struct phy_device *phydev, int addr, size_t priv_size)
+int phy_package_join(struct phy_device *phydev, int base_addr, size_t priv_size)
 {
 	struct mii_bus *bus = phydev->mdio.bus;
 	struct phy_package_shared *shared;
 	int ret;
 
-	if (addr < 0 || addr >= PHY_MAX_ADDR)
+	if (base_addr < 0 || base_addr >= PHY_MAX_ADDR)
 		return -EINVAL;
 
 	mutex_lock(&bus->shared_lock);
-	shared = bus->shared[addr];
+	shared = bus->shared[base_addr];
 	if (!shared) {
 		ret = -ENOMEM;
 		shared = kzalloc(sizeof(*shared), GFP_KERNEL);
@@ -1696,9 +1698,9 @@ int phy_package_join(struct phy_device *phydev, int addr, size_t priv_size)
 				goto err_free;
 			shared->priv_size = priv_size;
 		}
-		shared->addr = addr;
+		shared->base_addr = base_addr;
 		refcount_set(&shared->refcnt, 1);
-		bus->shared[addr] = shared;
+		bus->shared[base_addr] = shared;
 	} else {
 		ret = -EINVAL;
 		if (priv_size && priv_size != shared->priv_size)
@@ -1736,7 +1738,7 @@ void phy_package_leave(struct phy_device *phydev)
 		return;
 
 	if (refcount_dec_and_mutex_lock(&shared->refcnt, &bus->shared_lock)) {
-		bus->shared[shared->addr] = NULL;
+		bus->shared[shared->base_addr] = NULL;
 		mutex_unlock(&bus->shared_lock);
 		kfree(shared->priv);
 		kfree(shared);
@@ -1755,7 +1757,8 @@ static void devm_phy_package_leave(struct device *dev, void *res)
  * devm_phy_package_join - resource managed phy_package_join()
  * @dev: device that is registering this PHY package
  * @phydev: target phy_device struct
- * @addr: cookie and PHY address for global register access
+ * @base_addr: cookie and base PHY address of PHY package for offset
+ *   calculation of global register access
  * @priv_size: if non-zero allocate this amount of bytes for private data
  *
  * Managed phy_package_join(). Shared storage fetched by this function,
@@ -1763,7 +1766,7 @@ static void devm_phy_package_leave(struct device *dev, void *res)
  * phy_package_join() for more information.
  */
 int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
-			  int addr, size_t priv_size)
+			  int base_addr, size_t priv_size)
 {
 	struct phy_device **ptr;
 	int ret;
@@ -1773,7 +1776,7 @@ int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
 	if (!ptr)
 		return -ENOMEM;
 
-	ret = phy_package_join(phydev, addr, priv_size);
+	ret = phy_package_join(phydev, base_addr, priv_size);
 
 	if (!ret) {
 		*ptr = phydev;