It has the same PTP IP block as lan8814, only the number of GPIOs is
different, all the other functionality is the same. So reuse the same
functions as lan8814 for lan8842.
There is a revision of lan8842 called lan8832 which doesn't have the PTP
IP block. So make sure in that case the PTP is not initialized.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 drivers/net/phy/micrel.c | 97 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 9a90818481320..628f21ad262ce 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -457,6 +457,8 @@ struct lan8842_phy_stats {
 
 struct lan8842_priv {
 	struct lan8842_phy_stats phy_stats;
+	struct kszphy_ptp_priv ptp_priv;
+	u16 rev;
 };
 
 static const struct kszphy_type lan8814_type = {
@@ -5786,6 +5788,17 @@ static int ksz9131_resume(struct phy_device *phydev)
 	return kszphy_resume(phydev);
 }
 
+#define LAN8842_PTP_GPIO_NUM 16
+
+static int lan8842_ptp_probe_once(struct phy_device *phydev)
+{
+	return __lan8814_ptp_probe_once(phydev, "lan8842_ptp_pin",
+					LAN8842_PTP_GPIO_NUM);
+}
+
+#define LAN8842_STRAP_REG			0 /* 0x0 */
+#define LAN8842_STRAP_REG_PHYADDR_MASK		GENMASK(4, 0)
+#define LAN8842_SKU_REG				11 /* 0x0b */
 #define LAN8842_SELF_TEST			14 /* 0x0e */
 #define LAN8842_SELF_TEST_RX_CNT_ENA		BIT(8)
 #define LAN8842_SELF_TEST_TX_CNT_ENA		BIT(4)
@@ -5793,6 +5806,7 @@ static int ksz9131_resume(struct phy_device *phydev)
 static int lan8842_probe(struct phy_device *phydev)
 {
 	struct lan8842_priv *priv;
+	int addr;
 	int ret;
 
 	priv = devm_kzalloc(&phydev->mdio.dev, sizeof(*priv), GFP_KERNEL);
@@ -5817,6 +5831,43 @@ static int lan8842_probe(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
+	/* Revision lan8832 doesn't have support for PTP, therefore don't add
+	 * any PTP clocks
+	 */
+	ret = lanphy_read_page_reg(phydev, LAN8814_PAGE_COMMON_REGS,
+				   LAN8842_SKU_REG);
+	if (ret < 0)
+		return ret;
+
+	priv->rev = ret;
+	if (priv->rev == 0x8832)
+		return 0;
+
+	/* As the lan8814 and lan8842 has the same IP for the PTP block, the
+	 * only difference is the number of the GPIOs, then make sure that the
+	 * lan8842 initialized also the shared data pointer as this is used in
+	 * all the PTP functions for lan8814. The lan8842 doesn't have multiple
+	 * PHYs in the same package.
+	 */
+	addr = lanphy_read_page_reg(phydev, LAN8814_PAGE_COMMON_REGS,
+				    LAN8842_STRAP_REG);
+	if (addr < 0)
+		return addr;
+	addr &= LAN8842_STRAP_REG_PHYADDR_MASK;
+
+	ret = devm_phy_package_join(&phydev->mdio.dev, phydev, addr,
+				    sizeof(struct lan8814_shared_priv));
+	if (ret)
+		return ret;
+
+	if (phy_package_init_once(phydev)) {
+		ret = lan8842_ptp_probe_once(phydev);
+		if (ret)
+			return ret;
+	}
+
+	lan8814_ptp_init(phydev);
+
 	return 0;
 }
 
@@ -5896,8 +5947,34 @@ static int lan8842_config_inband(struct phy_device *phydev, unsigned int modes)
 				      enable ? LAN8814_QSGMII_PCS1G_ANEG_CONFIG_ANEG_ENA : 0);
 }
 
+static void lan8842_handle_ptp_interrupt(struct phy_device *phydev, u16 status)
+{
+	struct kszphy_ptp_priv *ptp_priv;
+	struct lan8842_priv *priv;
+
+	priv = phydev->priv;
+	ptp_priv = &priv->ptp_priv;
+
+	if (status & PTP_TSU_INT_STS_PTP_TX_TS_EN_)
+		lan8814_get_tx_ts(ptp_priv);
+
+	if (status & PTP_TSU_INT_STS_PTP_RX_TS_EN_)
+		lan8814_get_rx_ts(ptp_priv);
+
+	if (status & PTP_TSU_INT_STS_PTP_TX_TS_OVRFL_INT_) {
+		lan8814_flush_fifo(phydev, true);
+		skb_queue_purge(&ptp_priv->tx_queue);
+	}
+
+	if (status & PTP_TSU_INT_STS_PTP_RX_TS_OVRFL_INT_) {
+		lan8814_flush_fifo(phydev, false);
+		skb_queue_purge(&ptp_priv->rx_queue);
+	}
+}
+
 static irqreturn_t lan8842_handle_interrupt(struct phy_device *phydev)
 {
+	struct lan8842_priv *priv = phydev->priv;
 	int ret = IRQ_NONE;
 	int irq_status;
 
@@ -5912,6 +5989,26 @@ static irqreturn_t lan8842_handle_interrupt(struct phy_device *phydev)
 		ret = IRQ_HANDLED;
 	}
 
+	/* Phy revision lan8832 doesn't have support for PTP threrefore there is
+	 * not need to check the PTP and GPIO interrupts
+	 */
+	if (priv->rev == 0x8832)
+		goto out;
+
+	while (true) {
+		irq_status = lanphy_read_page_reg(phydev, LAN8814_PAGE_PORT_REGS,
+						  PTP_TSU_INT_STS);
+		if (!irq_status)
+			break;
+
+		lan8842_handle_ptp_interrupt(phydev, irq_status);
+		ret = IRQ_HANDLED;
+	}
+
+	if (!lan8814_handle_gpio_interrupt(phydev, irq_status))
+		ret = IRQ_HANDLED;
+
+out:
 	return ret;
 }
 
-- 
2.34.1

On Fri, 29 Aug 2025 15:48:36 +0200
Horatiu Vultur <horatiu.vultur@microchip.com> wrote:

> It has the same PTP IP block as lan8814, only the number of GPIOs is
> different, all the other functionality is the same. So reuse the same
> functions as lan8814 for lan8842.
> There is a revision of lan8842 called lan8832 which doesn't have the PTP
> IP block. So make sure in that case the PTP is not initialized.

...
 
> @@ -5817,6 +5831,43 @@ static int lan8842_probe(struct phy_device *phydev)
>  	if (ret < 0)
>  		return ret;
>  
> +	/* Revision lan8832 doesn't have support for PTP, therefore don't add
> +	 * any PTP clocks
> +	 */
> +	ret = lanphy_read_page_reg(phydev, LAN8814_PAGE_COMMON_REGS,
> +				   LAN8842_SKU_REG);
> +	if (ret < 0)
> +		return ret;
> +
> +	priv->rev = ret;
> +	if (priv->rev == 0x8832)
> +		return 0;

Is the lan8832 PHY ID the same as the lan8842? This would be surprising.
If they have different PHY ID, it will never enter the lan8842 probe function as
it is not added to mdio_device_id.
Also you should add a define instead of using several time 0x8832.

...

> @@ -5912,6 +5989,26 @@ static irqreturn_t lan8842_handle_interrupt(struct
> phy_device *phydev) ret = IRQ_HANDLED;
>  	}
>  
> +	/* Phy revision lan8832 doesn't have support for PTP threrefore

nitpick: therefore

Regards,
-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

The 08/29/2025 16:53, Kory Maincent wrote:
> 
> On Fri, 29 Aug 2025 15:48:36 +0200
> Horatiu Vultur <horatiu.vultur@microchip.com> wrote:
> 
> > It has the same PTP IP block as lan8814, only the number of GPIOs is
> > different, all the other functionality is the same. So reuse the same
> > functions as lan8814 for lan8842.
> > There is a revision of lan8842 called lan8832 which doesn't have the PTP
> > IP block. So make sure in that case the PTP is not initialized.
> 
> ...
> 
> > @@ -5817,6 +5831,43 @@ static int lan8842_probe(struct phy_device *phydev)
> >       if (ret < 0)
> >               return ret;
> >
> > +     /* Revision lan8832 doesn't have support for PTP, therefore don't add
> > +      * any PTP clocks
> > +      */
> > +     ret = lanphy_read_page_reg(phydev, LAN8814_PAGE_COMMON_REGS,
> > +                                LAN8842_SKU_REG);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     priv->rev = ret;
> > +     if (priv->rev == 0x8832)
> > +             return 0;
> 
> Is the lan8832 PHY ID the same as the lan8842? This would be surprising.
> If they have different PHY ID, it will never enter the lan8842 probe function as
> it is not added to mdio_device_id.
> Also you should add a define instead of using several time 0x8832.

They will have the same PHY ID. And it is the LAN8842_SKU_REG which
determines which revision of the PHY it is.
I will add a define for 0x8832.
> 
> ...
> 
> > @@ -5912,6 +5989,26 @@ static irqreturn_t lan8842_handle_interrupt(struct
> > phy_device *phydev) ret = IRQ_HANDLED;
> >       }
> >
> > +     /* Phy revision lan8832 doesn't have support for PTP threrefore
> 
> nitpick: therefore

Good catch. I will fix this in the next version.

> 
> Regards,
> --
> Köry Maincent, Bootlin
> Embedded Linux and kernel engineering
> https://bootlin.com

-- 
/Horatiu