[PATCH net 11/11] net: phy: smsc: wait for LAN83C183 power-down recovery

[Florian Fainelli <f.fainelli@gmail.com>]

The LAN83C183 uses the generic PHY driver, which returns immediately
after clearing BMCR_PDOWN. Section 1.11 of the datasheet allows 500 ms
before normal operation is restored. Starting the Au1000 MAC before the
MII clocks recover can hang the MTX-1 when reopening its interface.

Add a LAN83C183 driver entry and resume callback. Wait for recovery only
when BMCR_PDOWN was actually cleared, and propagate MDIO errors without
waiting. Resuming an already awake PHY does not incur the delay.

Fixes: be9dad1f9f26 ("net: phy: suspend phydev when going to HALTED")
Link: https://pdf.dzsc.com/LAN/LAN83C183.pdf#page=44
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/phy/Kconfig |  2 +-
 drivers/net/phy/smsc.c  | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 30e9d22c8d1a..10466b2574eb 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -421,7 +421,7 @@ config SMSC_PHY
 	tristate "SMSC PHYs"
 	select CRC16
 	help
-	  Currently supports the LAN83C185, LAN8187 and LAN8700 PHYs
+	  Currently supports the LAN83C183, LAN83C185, LAN8187 and LAN8700 PHYs
 
 config STE10XP
 	tristate "STMicroelectronics STe10Xp PHYs"
diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index 48487149c225..c3b51afd4b1e 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mii.h>
@@ -684,8 +685,32 @@ int smsc_phy_probe(struct phy_device *phydev)
 }
 EXPORT_SYMBOL_GPL(smsc_phy_probe);
 
+static int lan83c183_resume(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_modify_changed(phydev, MII_BMCR, BMCR_PDOWN, 0);
+	if (ret < 0)
+		return ret;
+
+	/* The PHY needs up to 500 ms to restore operation after power-down. */
+	if (ret)
+		msleep(500);
+
+	return 0;
+}
+
 static struct phy_driver smsc_phy_driver[] = {
 {
+	.phy_id		= 0x0016f840,
+	.phy_id_mask	= 0xfffffff0,
+	.name		= "SMSC LAN83C183",
+
+	.get_features	= genphy_read_abilities,
+	.suspend	= genphy_suspend,
+	.resume		= lan83c183_resume,
+	.set_loopback	= genphy_loopback,
+}, {
 	.phy_id		= 0x0007c0a0, /* OUI=0x00800f, Model#=0x0a */
 	.phy_id_mask	= 0xfffffff0,
 	.name		= "SMSC LAN83C185",
@@ -887,6 +912,7 @@ MODULE_AUTHOR("Herbert Valerio Riedel");
 MODULE_LICENSE("GPL");
 
 static const struct mdio_device_id __maybe_unused smsc_tbl[] = {
+	{ 0x0016f840, 0xfffffff0 },
 	{ 0x0007c0a0, 0xfffffff0 },
 	{ 0x0007c0b0, 0xfffffff0 },
 	{ 0x0007c0c0, 0xfffffff0 },
-- 
2.53.0