[RFC PATCH net-next 4/9] net: pcs: lynx: Convert to an mdio driver

[Sean Anderson <sean.anderson@seco.com>]

This converts the lynx PCS driver to a proper MDIO driver. This allows
using a more conventional driver lifecycle (e.g. with a probe and
remove). For compatibility with existing device trees lacking a
compatible property, we bind the driver in lynx_pcs_create. This is
intended only as a transitional method. After compatible properties are
added to all existing device trees (and a reasonable amount of time has
passed), then lynx_pcs_create can be removed, and users can be converted
to pcs_get_fwnode.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
---

 drivers/net/dsa/ocelot/Kconfig                |  2 +
 drivers/net/dsa/ocelot/felix_vsc9959.c        |  2 +-
 drivers/net/dsa/ocelot/seville_vsc9953.c      |  2 +-
 drivers/net/ethernet/freescale/dpaa2/Kconfig  |  1 +
 .../net/ethernet/freescale/dpaa2/dpaa2-mac.c  |  4 +-
 drivers/net/ethernet/freescale/enetc/Kconfig  |  1 +
 .../net/ethernet/freescale/enetc/enetc_pf.c   |  4 +-
 drivers/net/pcs/Kconfig                       | 11 +++-
 drivers/net/pcs/pcs-lynx.c                    | 65 +++++++++++++++----
 9 files changed, 72 insertions(+), 20 deletions(-)

diff --git a/drivers/net/dsa/ocelot/Kconfig b/drivers/net/dsa/ocelot/Kconfig
index 220b0b027b55..cbb0ced3f37d 100644
--- a/drivers/net/dsa/ocelot/Kconfig
+++ b/drivers/net/dsa/ocelot/Kconfig
@@ -10,6 +10,7 @@ config NET_DSA_MSCC_FELIX
 	select NET_DSA_TAG_OCELOT_8021Q
 	select NET_DSA_TAG_OCELOT
 	select FSL_ENETC_MDIO
+	select PCS
 	select PCS_LYNX
 	help
 	  This driver supports the VSC9959 (Felix) switch, which is embedded as
@@ -25,6 +26,7 @@ config NET_DSA_MSCC_SEVILLE
 	select MSCC_OCELOT_SWITCH_LIB
 	select NET_DSA_TAG_OCELOT_8021Q
 	select NET_DSA_TAG_OCELOT
+	select PCS
 	select PCS_LYNX
 	help
 	  This driver supports the VSC9953 (Seville) switch, which is embedded
diff --git a/drivers/net/dsa/ocelot/felix_vsc9959.c b/drivers/net/dsa/ocelot/felix_vsc9959.c
index 570d0204b7be..57634e2296c0 100644
--- a/drivers/net/dsa/ocelot/felix_vsc9959.c
+++ b/drivers/net/dsa/ocelot/felix_vsc9959.c
@@ -1094,7 +1094,7 @@ static int vsc9959_mdio_bus_alloc(struct ocelot *ocelot)
 			continue;
 
 		phylink_pcs = lynx_pcs_create(mdio_device);
-		if (!phylink_pcs) {
+		if (IS_ERR(phylink_pcs)) {
 			mdio_device_free(mdio_device);
 			continue;
 		}
diff --git a/drivers/net/dsa/ocelot/seville_vsc9953.c b/drivers/net/dsa/ocelot/seville_vsc9953.c
index ea0649211356..8c52de5d0b02 100644
--- a/drivers/net/dsa/ocelot/seville_vsc9953.c
+++ b/drivers/net/dsa/ocelot/seville_vsc9953.c
@@ -1049,7 +1049,7 @@ static int vsc9953_mdio_bus_alloc(struct ocelot *ocelot)
 			continue;
 
 		phylink_pcs = lynx_pcs_create(mdio_device);
-		if (!phylink_pcs) {
+		if (IS_ERR(phylink_pcs)) {
 			mdio_device_free(mdio_device);
 			continue;
 		}
diff --git a/drivers/net/ethernet/freescale/dpaa2/Kconfig b/drivers/net/ethernet/freescale/dpaa2/Kconfig
index d029b69c3f18..2648e9fb6e13 100644
--- a/drivers/net/ethernet/freescale/dpaa2/Kconfig
+++ b/drivers/net/ethernet/freescale/dpaa2/Kconfig
@@ -3,6 +3,7 @@ config FSL_DPAA2_ETH
 	tristate "Freescale DPAA2 Ethernet"
 	depends on FSL_MC_BUS && FSL_MC_DPIO
 	select PHYLINK
+	select PCS
 	select PCS_LYNX
 	select FSL_XGMAC_MDIO
 	select NET_DEVLINK
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
index c9bee9a0c9b2..e82c0d23eeb5 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
@@ -268,10 +268,10 @@ static int dpaa2_pcs_create(struct dpaa2_mac *mac,
 		return -EPROBE_DEFER;
 
 	mac->pcs = lynx_pcs_create(mdiodev);
-	if (!mac->pcs) {
+	if (IS_ERR(mac->pcs)) {
 		netdev_err(mac->net_dev, "lynx_pcs_create() failed\n");
 		put_device(&mdiodev->dev);
-		return -ENOMEM;
+		return PTR_ERR(mac->pcs);
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/freescale/enetc/Kconfig b/drivers/net/ethernet/freescale/enetc/Kconfig
index cdc0ff89388a..c7dcdeb9a333 100644
--- a/drivers/net/ethernet/freescale/enetc/Kconfig
+++ b/drivers/net/ethernet/freescale/enetc/Kconfig
@@ -5,6 +5,7 @@ config FSL_ENETC
 	select FSL_ENETC_IERB
 	select FSL_ENETC_MDIO
 	select PHYLINK
+	select PCS
 	select PCS_LYNX
 	select DIMLIB
 	help
diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
index c4a0e836d4f0..8c923a93da88 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
@@ -859,9 +859,9 @@ static int enetc_imdio_create(struct enetc_pf *pf)
 	}
 
 	phylink_pcs = lynx_pcs_create(mdio_device);
-	if (!phylink_pcs) {
+	if (IS_ERR(phylink_pcs)) {
 		mdio_device_free(mdio_device);
-		err = -ENOMEM;
+		err = PTR_ERR(phylink_pcs);
 		dev_err(dev, "cannot create lynx pcs (%d)\n", err);
 		goto unregister_mdiobus;
 	}
diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig
index fed6264fdf33..a225176f92e8 100644
--- a/drivers/net/pcs/Kconfig
+++ b/drivers/net/pcs/Kconfig
@@ -25,9 +25,14 @@ config PCS_XPCS
 	  controllers.
 
 config PCS_LYNX
-	tristate
+	tristate "NXP Lynx PCS driver"
+	depends on PCS && MDIO_DEVICE
 	help
-	  This module provides helpers to phylink for managing the Lynx PCS
-	  which is part of the Layerscape and QorIQ Ethernet SERDES.
+	  This module provides driver support for the PCSs in Lynx 10g and 28g
+	  SerDes devices. These devices are present in NXP QorIQ SoCs,
+	  including the Layerscape series.
+
+	  If you want to use Ethernet on a QorIQ SoC, say "Y". If compiled as a
+	  module, it will be called "pcs-lynx".
 
 endmenu
diff --git a/drivers/net/pcs/pcs-lynx.c b/drivers/net/pcs/pcs-lynx.c
index fd3445374955..8272072698e4 100644
--- a/drivers/net/pcs/pcs-lynx.c
+++ b/drivers/net/pcs/pcs-lynx.c
@@ -1,11 +1,14 @@
-// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
-/* Copyright 2020 NXP
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2022 Sean Anderson <seanga2@gmail.com>
+ * Copyright 2020 NXP
  * Lynx PCS MDIO helpers
  */
 
 #include <linux/mdio.h>
-#include <linux/phylink.h>
+#include <linux/of.h>
+#include <linux/pcs.h>
 #include <linux/pcs-lynx.h>
+#include <linux/phylink.h>
 
 #define SGMII_CLOCK_PERIOD_NS		8 /* PCS is clocked at 125 MHz */
 #define LINK_TIMER_VAL(ns)		((u32)((ns) / SGMII_CLOCK_PERIOD_NS))
@@ -337,34 +340,74 @@ static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
 }
 
 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
+	.owner = THIS_MODULE,
 	.pcs_get_state = lynx_pcs_get_state,
 	.pcs_config = lynx_pcs_config,
 	.pcs_an_restart = lynx_pcs_an_restart,
 	.pcs_link_up = lynx_pcs_link_up,
 };
 
-struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
+static int lynx_pcs_probe(struct mdio_device *mdio)
 {
+	struct device *dev = &mdio->dev;
 	struct lynx_pcs *lynx;
+	int ret;
 
-	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
+	lynx = devm_kzalloc(dev, sizeof(*lynx), GFP_KERNEL);
 	if (!lynx)
-		return NULL;
+		return -ENOMEM;
 
 	lynx->mdio = mdio;
+	lynx->pcs.dev = dev;
 	lynx->pcs.ops = &lynx_pcs_phylink_ops;
 	lynx->pcs.poll = true;
 
-	return lynx_to_phylink_pcs(lynx);
+	ret = devm_pcs_register(dev, &lynx->pcs);
+	if (ret)
+		return dev_err_probe(dev, ret, "could not register PCS\n");
+	dev_info(dev, "probed\n");
+	return 0;
+}
+
+static const struct of_device_id lynx_pcs_of_match[] = {
+	{ .compatible = "fsl,lynx-pcs" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, lynx_pcs_of_match);
+
+static struct mdio_driver lynx_pcs_driver = {
+	.probe = lynx_pcs_probe,
+	.mdiodrv.driver = {
+		.name = "lynx-pcs",
+		.of_match_table = of_match_ptr(lynx_pcs_of_match),
+	},
+};
+mdio_module_driver(lynx_pcs_driver);
+
+struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
+{
+	struct device *dev = &mdio->dev;
+	int err;
+
+	/* For compatibility with device trees lacking compatible strings, we
+	 * bind the device manually here.
+	 */
+	err = device_driver_attach(&lynx_pcs_driver.mdiodrv.driver, dev);
+	if (err && err != -EBUSY) {
+		if (err == -EAGAIN)
+			err = -EPROBE_DEFER;
+		return ERR_PTR(err);
+	}
+
+	return pcs_get_by_provider(&mdio->dev);
 }
 EXPORT_SYMBOL(lynx_pcs_create);
 
 void lynx_pcs_destroy(struct phylink_pcs *pcs)
 {
-	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
-
-	kfree(lynx);
+	pcs_put(pcs);
 }
 EXPORT_SYMBOL(lynx_pcs_destroy);
 
-MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("NXP Lynx 10G/28G PCS driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1.1320.gc452695387.dirty