On Wed, Aug 20, 2025 at 06:09:13PM +0100, Prabhakar wrote: > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > 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@xxxxxxxxxx > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > Reviewed-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> I had a look now. Because the bootloader of my N1D board already set up MODCTRL correctly, this write to the wrong register went unnoticed. I verified that the now correctly written value (depending on DT config) matches the value previously set by the bootloader. As a result, everything keeps working. We were lucky. Or unlucky. Depending how you look at it. Tested-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> Thanks for this fix!
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