netdev - [PATCH net-next 2/2] net: phy: bcm7xxx: request and manage GPHY clock

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Message-Id: <20200916204415.1831417-3-f.fainelli@gmail.com>
Date:   Wed, 16 Sep 2020 13:44:15 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     netdev@...r.kernel.org
Cc:     Florian Fainelli <f.fainelli@...il.com>, andrew@...n.ch,
        hkallweit1@...il.com, kuba@...nel.org, davem@...emloft.net
Subject: [PATCH net-next 2/2] net: phy: bcm7xxx: request and manage GPHY clock

The internal Gigabit PHY on Broadcom STB chips has a digital clock which
drives its MDIO interface among other things, the driver now requests
and manage that clock during .probe() and .remove() accordingly.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/net/phy/bcm7xxx.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/bcm7xxx.c b/drivers/net/phy/bcm7xxx.c
index 692048d86ab1..aa70b322b119 100644
--- a/drivers/net/phy/bcm7xxx.c
+++ b/drivers/net/phy/bcm7xxx.c
@@ -11,6 +11,8 @@
 #include "bcm-phy-lib.h"
 #include <linux/bitops.h>
 #include <linux/brcmphy.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/mdio.h>
 
 /* Broadcom BCM7xxx internal PHY registers */
@@ -39,6 +41,7 @@
 
 struct bcm7xxx_phy_priv {
 	u64	*stats;
+	struct clk *clk;
 };
 
 static int bcm7xxx_28nm_d0_afe_config_init(struct phy_device *phydev)
@@ -521,6 +524,7 @@ static void bcm7xxx_28nm_get_phy_stats(struct phy_device *phydev,
 static int bcm7xxx_28nm_probe(struct phy_device *phydev)
 {
 	struct bcm7xxx_phy_priv *priv;
+	int ret = 0;
 
 	priv = devm_kzalloc(&phydev->mdio.dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -534,7 +538,29 @@ static int bcm7xxx_28nm_probe(struct phy_device *phydev)
 	if (!priv->stats)
 		return -ENOMEM;
 
-	return 0;
+	priv->clk = devm_clk_get_optional(&phydev->mdio.dev, NULL);
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	/* Do not increment the clock reference count here, the MDIO driver has
+	 * already done that in order to successfully enable the PHY during its
+	 * bus->reset() callback and get us past get_phy_device() which reads
+	 * the PHY ID and later matches against a given PHY driver. If we
+	 * incremented the reference count, a driver unbind would not be able
+	 * to turn off the clock.
+	 */
+	if (!__clk_is_enabled(priv->clk))
+		ret = clk_prepare_enable(priv->clk);
+
+	return ret;
+}
+
+static void bcm7xxx_28nm_remove(struct phy_device *phydev)
+{
+	struct bcm7xxx_phy_priv *priv = phydev->priv;
+
+	clk_disable_unprepare(priv->clk);
+	devm_clk_put(&phydev->mdio.dev, priv->clk);
 }
 
 #define BCM7XXX_28NM_GPHY(_oui, _name)					\
@@ -552,6 +578,7 @@ static int bcm7xxx_28nm_probe(struct phy_device *phydev)
 	.get_strings	= bcm_phy_get_strings,				\
 	.get_stats	= bcm7xxx_28nm_get_phy_stats,			\
 	.probe		= bcm7xxx_28nm_probe,				\
+	.remove		= bcm7xxx_28nm_remove,				\
 }
 
 #define BCM7XXX_28NM_EPHY(_oui, _name)					\
@@ -567,6 +594,7 @@ static int bcm7xxx_28nm_probe(struct phy_device *phydev)
 	.get_strings	= bcm_phy_get_strings,				\
 	.get_stats	= bcm7xxx_28nm_get_phy_stats,			\
 	.probe		= bcm7xxx_28nm_probe,				\
+	.remove		= bcm7xxx_28nm_remove,				\
 }
 
 #define BCM7XXX_40NM_EPHY(_oui, _name)					\
-- 
2.25.1