[PATCH v3] net: pcs: rzn1-miic: Correct MODCTRL register offset

[PATCH v3] net: pcs: rzn1-miic: Correct MODCTRL register offset

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Correct the Mode Control Register (MODCTRL) offset for RZ/N MIIC.
According to the R-IN Engine and Ethernet Peripherals Manual (Rev.1.30)
[0], Table 10.1 "Ethernet Accessory Register List", MODCTRL is at offset
0x8, not 0x20 as previously defined.

Offset 0x20 actually maps to the Port Trigger Control Register (PTCTRL),
which controls PTP_MODE[3:0] and RGMII_CLKSEL[4]. Using this incorrect
definition prevented the driver from configuring the SW_MODE[4:0] bits
in MODCTRL, which control the internal connection of Ethernet ports. As
a result, the MIIC could not be switched into the correct mode, leading
to link setup failures and non-functional Ethernet ports on affected
systems.

[0] https://www.renesas.com/en/document/mah/rzn1d-group-rzn1s-group-rzn1l-group-users-manual-r-engine-and-ethernet-peripherals?r=1054571

Fixes: 7dc54d3b8d91 ("net: pcs: add Renesas MII converter driver")
Cc: stable@kernel.org
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
v2->v3:
- Dropped net-next prefix as this is a fix.
- Added tested-by tag from Wolfram.

v1->v2:
- Used correct subject prefix
- Updated commit message to clarify the issue.
---
 drivers/net/pcs/pcs-rzn1-miic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index d79bb9b06cd2..ce73d9474d5b 100644
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -19,7 +19,7 @@
 #define MIIC_PRCMD			0x0
 #define MIIC_ESID_CODE			0x4
 
-#define MIIC_MODCTRL			0x20
+#define MIIC_MODCTRL			0x8
 #define MIIC_MODCTRL_SW_MODE		GENMASK(4, 0)
 
 #define MIIC_CONVCTRL(port)		(0x100 + (port) * 4)
-- 
2.51.0

Re: [PATCH v3] net: pcs: rzn1-miic: Correct MODCTRL register offset

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon,  1 Sep 2025 12:20:19 +0100 you wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> Correct the Mode Control Register (MODCTRL) offset for RZ/N MIIC.
> According to the R-IN Engine and Ethernet Peripherals Manual (Rev.1.30)
> [0], Table 10.1 "Ethernet Accessory Register List", MODCTRL is at offset
> 0x8, not 0x20 as previously defined.
> 
> [...]

Here is the summary with links:
  - [v3] net: pcs: rzn1-miic: Correct MODCTRL register offset
    https://git.kernel.org/netdev/net/c/a7195a3d67da

You are awesome, thank you!
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