[PATCH net-next 2/9] net: phy: dp83867: add regulator supply management

[Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>]

Some embedded board designs use GPIO-controlled regulators for the
DP83867 power rails. Add dp83867_power_on() to enable all four supply
domains at probe time. Absent supplies are silently skipped, so boards
that do not describe them are unaffected.

When any supply is newly enabled the driver sleeps for 200 ms before
returning.  This satisfies the post power-up stabilisation requirement
mentioned in section 6.6 of the DP83867E/IS/CS datasheet.

Signed-off-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>
---
 drivers/net/phy/dp83867.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index 88255e92b4cdbd6da2e2c1d10f9c72348d28dbc3..e03b39fd080d12afe0d02a53ffef2a6adf73cd9f 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -15,6 +15,7 @@
 #include <linux/etherdevice.h>
 #include <linux/bitfield.h>
 #include <linux/nvmem-consumer.h>
+#include <linux/regulator/consumer.h>
 
 #include <dt-bindings/net/ti-dp83867.h>
 
@@ -719,9 +720,40 @@ static int dp83867_resume(struct phy_device *phydev)
 	return 0;
 }
 
+static int dp83867_power_on(struct phy_device *phydev)
+{
+	static const char * const supply_names[] = {
+		"vdda-2p5", "vdd-1p0", "vdda-1p8", "vddio",
+	};
+	struct device *dev = &phydev->mdio.dev;
+	u32 count = 0;
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(supply_names); i++) {
+		ret = devm_regulator_get_enable_optional(dev, supply_names[i]);
+		if (!ret)
+			count++;
+		else if (ret != -ENODEV)
+			return dev_err_probe(dev, ret,
+					     "failed to enable %s supply\n",
+					     supply_names[i]);
+	}
+
+	/* Datasheet section 6.6 suggests a 200ms post power-up stabilization */
+	if (count)
+		fsleep(200000);
+
+	return 0;
+}
+
 static int dp83867_probe(struct phy_device *phydev)
 {
 	struct dp83867_private *dp83867;
+	int ret;
+
+	ret = dp83867_power_on(phydev);
+	if (ret)
+		return ret;
 
 	dp83867 = devm_kzalloc(&phydev->mdio.dev, sizeof(*dp83867),
 			       GFP_KERNEL);

-- 
2.34.1