linux-kernel - [PATCH net-next v4 14/14] net: dsa: b53: ensure BCM5325 PHYs are enabled

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Message-Id: <20250614080000.1884236-15-noltari@gmail.com>
Date: Sat, 14 Jun 2025 10:00:00 +0200
From: Álvaro Fernández Rojas <noltari@...il.com>
To: jonas.gorski@...il.com,
	florian.fainelli@...adcom.com,
	andrew@...n.ch,
	olteanv@...il.com,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org,
	vivien.didelot@...il.com,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	dgcbueu@...il.com
Cc: Álvaro Fernández Rojas <noltari@...il.com>
Subject: [PATCH net-next v4 14/14] net: dsa: b53: ensure BCM5325 PHYs are enabled

According to the datasheet, BCM5325 uses B53_PD_MODE_CTRL_25 register to
disable clocking to individual PHYs.
Only ports 1-4 can be enabled or disabled and the datasheet is explicit
about not toggling BIT(0) since it disables the PLL power and the switch.

Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
---
 drivers/net/dsa/b53/b53_common.c | 13 +++++++++++++
 drivers/net/dsa/b53/b53_regs.h   |  5 ++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

 v4: add changes requested by Jonas:
  - Avoid in_range() confusion.
  - Ensure PD_MODE_POWER_DOWN_PORT(0) is cleared.
  - Improve B53_PD_MODE_CTRL_25 register defines.

 v3: add changes requested by Florian:
  - Use in_range() helper.

 v2: add changes requested by Florian:
  - Move B53_PD_MODE_CTRL_25 to b53_setup_port().

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 29f207a69b9c..46978757c972 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -660,6 +660,19 @@ int b53_setup_port(struct dsa_switch *ds, int port)
 	if (dsa_is_user_port(ds, port))
 		b53_set_eap_mode(dev, port, EAP_MODE_SIMPLIFIED);
 
+	if (is5325(dev) &&
+	    in_range(port, 1, 4)) {
+		u8 reg;
+
+		b53_read8(dev, B53_CTRL_PAGE, B53_PD_MODE_CTRL_25, &reg);
+		reg &= ~PD_MODE_POWER_DOWN_PORT(0);
+		if (dsa_is_unused_port(ds, port))
+			reg |= PD_MODE_POWER_DOWN_PORT(port);
+		else
+			reg &= ~PD_MODE_POWER_DOWN_PORT(port);
+		b53_write8(dev, B53_CTRL_PAGE, B53_PD_MODE_CTRL_25, reg);
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL(b53_setup_port);
diff --git a/drivers/net/dsa/b53/b53_regs.h b/drivers/net/dsa/b53/b53_regs.h
index d6849cf6b0a3..309fe0e46dad 100644
--- a/drivers/net/dsa/b53/b53_regs.h
+++ b/drivers/net/dsa/b53/b53_regs.h
@@ -103,8 +103,11 @@
 #define   PORT_OVERRIDE_SPEED_2000M	BIT(6) /* BCM5301X only, requires setting 1000M */
 #define   PORT_OVERRIDE_EN		BIT(7) /* Use the register contents */
 
-/* Power-down mode control */
+/* Power-down mode control (8 bit) */
 #define B53_PD_MODE_CTRL_25		0x0f
+#define  PD_MODE_PORT_MASK		0x1f
+/* Bit 0 also powers down the switch. */
+#define  PD_MODE_POWER_DOWN_PORT(i)	BIT(i)
 
 /* IP Multicast control (8 bit) */
 #define B53_IP_MULTICAST_CTRL		0x21
-- 
2.39.5