[RFC PATCH net-next v2 10/10] net: dsa: b53: ensure BCM5325 PHYs are enabled

["Álvaro Fernández Rojas" <noltari@gmail.com>]

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@gmail.com>
---
 drivers/net/dsa/b53/b53_common.c | 13 +++++++++++++
 drivers/net/dsa/b53/b53_regs.h   |  2 ++
 2 files changed, 15 insertions(+)

 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 a9b19451ffb30..38c08f6278d27 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -659,6 +659,19 @@ 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) &&
+	    (port >= B53_PD_MODE_PORT_MIN) &&
+	    (port <= B53_PD_MODE_PORT_MAX)) {
+		u8 reg;
+
+		b53_read8(dev, B53_CTRL_PAGE, B53_PD_MODE_CTRL_25, &reg);
+		if (dsa_is_unused_port(ds, port))
+			reg |= BIT(port);
+		else
+			reg &= ~BIT(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 d6849cf6b0a3a..880c67130a9fc 100644
--- a/drivers/net/dsa/b53/b53_regs.h
+++ b/drivers/net/dsa/b53/b53_regs.h
@@ -105,6 +105,8 @@
 
 /* Power-down mode control */
 #define B53_PD_MODE_CTRL_25		0x0f
+#define  B53_PD_MODE_PORT_MIN		1
+#define  B53_PD_MODE_PORT_MAX		4
 
 /* IP Multicast control (8 bit) */
 #define B53_IP_MULTICAST_CTRL		0x21
-- 
2.39.5