[PATCH net v3] net: pcs: rzn1-miic: Reset PRCMD state before unprotect sequence
From: Yoshihisa Yamamoto <hidden>
Date: 2026-09-18 04:30:19
Also in:
linux-devicetree, linux-renesas-soc, lkml
Subsystem:
ethernet phy library, networking drivers, renesas rz/n1 a5psw switch driver, the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Clément Léger, Linus Torvalds
On RZ/T2H MIIC, writing 0x0000 to PRCMD resets the command state
machine to the IDLE state.
Reset PRCMD before issuing the unprotect sequence so that it always
starts from a known state, regardless of any previous PRCMD activity.
Fixes: 419747319e3a ("net: pcs: rzn1-miic: Add per-SoC control for MIIC register unlock/lock")
Signed-off-by: Yoshihisa Yamamoto <redacted>
---
v3:
- Add Fixes tag
v2: https://lore.kernel.org/all/TYCPR01MB748157ECB6B92D8E3FFD433BA4B82@TYCPR01MB7481.jpnprd01.prod.outlook.com (local)
- Fix indentation
v1: https://lore.kernel.org/all/TYCPR01MB748139F059DF2459B9813416A4B92@TYCPR01MB7481.jpnprd01.prod.outlook.com (local)
drivers/net/pcs/pcs-rzn1-miic.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index 2b72fa98d..818756bb8 100644
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c@@ -270,6 +270,9 @@ static struct miic_port *phylink_pcs_to_miic_port(struct phylink_pcs *pcs) static void miic_unlock_regs(struct miic *miic) { + /* Reset PRCMD state before unprotect sequence */ + writel(0x0000, miic->base + MIIC_PRCMD); + /* Unprotect register writes */ writel(0x00A5, miic->base + MIIC_PRCMD); writel(0x0001, miic->base + MIIC_PRCMD);
--
2.34.1