[PATCH net-next v2 08/10] net: pcs: xpcs: Add fwnode-based descriptor creation method

From: Serge Semin
Date: Sun Jun 02 2024 - 10:39:38 EST


It's now possible to have the DW XPCS device defined as a standard
platform device for instance in the platform DT-file. Although that
functionality is useless unless there is a way to have the device found by
the client drivers (STMMAC/DW *MAC, NXP SJA1105 Eth Switch, etc). Provide
such ability by means of the xpcs_create_fwnode() method. It needs to be
called with the device DW XPCS fwnode instance passed. That node will be
then used to find the MDIO-device instance in order to create the DW XPCS
descriptor.

Note the method semantics and name is similar to what has been recently
introduced in the Lynx PCS driver.

Signed-off-by: Serge Semin <fancer.lancer@xxxxxxxxx>

---

Changelog v2:
- Use the function name and semantics similar to the Lynx PCS driver.
- Add kdoc describing the DW XPCS create functions.
---
drivers/net/pcs/pcs-xpcs.c | 50 ++++++++++++++++++++++++++++++++++++
include/linux/pcs/pcs-xpcs.h | 3 +++
2 files changed, 53 insertions(+)

diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index 8f7e3af64fcc..d45fa6514884 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -10,7 +10,9 @@
#include <linux/delay.h>
#include <linux/pcs/pcs-xpcs.h>
#include <linux/mdio.h>
+#include <linux/phy.h>
#include <linux/phylink.h>
+#include <linux/property.h>

#include "pcs-xpcs.h"

@@ -1505,6 +1507,16 @@ static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
return ERR_PTR(ret);
}

+/**
+ * xpcs_create_mdiodev() - create a DW xPCS instance with the MDIO @addr
+ * @bus: pointer to the MDIO-bus descriptor for the device to be looked at
+ * @addr: device MDIO-bus ID
+ * @requested PHY interface
+ *
+ * If successful, returns a pointer to the DW XPCS handle. Otherwise returns
+ * -ENODEV if device couldn't be found on the bus, other negative errno related
+ * to the data allocation and MDIO-bus communications.
+ */
struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
phy_interface_t interface)
{
@@ -1529,6 +1541,44 @@ struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
}
EXPORT_SYMBOL_GPL(xpcs_create_mdiodev);

+/**
+ * xpcs_create_fwnode() - Create a DW xPCS instance from @fwnode
+ * @node: fwnode handle poining to the DW XPCS device
+ * @interface: requested PHY interface
+ *
+ * If successful, returns a pointer to the DW XPCS handle. Otherwise returns
+ * -ENODEV if the fwnode is marked unavailable or device couldn't be found on
+ * the bus, -EPROBE_DEFER if the respective MDIO-device instance couldn't be
+ * found, other negative errno related to the data allocations and MDIO-bus
+ * communications.
+ */
+struct dw_xpcs *xpcs_create_fwnode(struct fwnode_handle *fwnode,
+ phy_interface_t interface)
+{
+ struct mdio_device *mdiodev;
+ struct dw_xpcs *xpcs;
+
+ if (!fwnode_device_is_available(fwnode))
+ return ERR_PTR(-ENODEV);
+
+ mdiodev = fwnode_mdio_find_device(fwnode);
+ if (!mdiodev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ xpcs = xpcs_create(mdiodev, interface);
+
+ /* xpcs_create() has taken a refcount on the mdiodev if it was
+ * successful. If xpcs_create() fails, this will free the mdio
+ * device here. In any case, we don't need to hold our reference
+ * anymore, and putting it here will allow mdio_device_put() in
+ * xpcs_destroy() to automatically free the mdio device.
+ */
+ mdio_device_put(mdiodev);
+
+ return xpcs;
+}
+EXPORT_SYMBOL_GPL(xpcs_create_fwnode);
+
void xpcs_destroy(struct dw_xpcs *xpcs)
{
if (!xpcs)
diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
index 813be644647f..b4a4eb6c8866 100644
--- a/include/linux/pcs/pcs-xpcs.h
+++ b/include/linux/pcs/pcs-xpcs.h
@@ -8,6 +8,7 @@
#define __LINUX_PCS_XPCS_H

#include <linux/clk.h>
+#include <linux/fwnode.h>
#include <linux/mdio.h>
#include <linux/phy.h>
#include <linux/phylink.h>
@@ -72,6 +73,8 @@ int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns,
int enable);
struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
phy_interface_t interface);
+struct dw_xpcs *xpcs_create_fwnode(struct fwnode_handle *fwnode,
+ phy_interface_t interface);
void xpcs_destroy(struct dw_xpcs *xpcs);

#endif /* __LINUX_PCS_XPCS_H */
--
2.43.0