From e2b1d186d75a4af26ba06f94282f953b79b6bad6 Mon Sep 17 00:00:00 2001
From: Jani Paalijarvi <jani.paalijarvi@unikie.com>
Date: Wed, 20 Nov 2024 14:33:50 +0200
Subject: [PATCH] drivers/net/ksz9477.c: Errata 16, reset SGMII always on init

---
 drivers/net/ksz9477.c     | 8 ++++++++
 drivers/net/ksz9477_reg.h | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/net/ksz9477.c b/drivers/net/ksz9477.c
index cbce7506c45..296dfc797d5 100644
--- a/drivers/net/ksz9477.c
+++ b/drivers/net/ksz9477.c
@@ -640,6 +640,14 @@ int ksz9477_init(ksz9477_port_t master_port)
       return ret ? ret : -EINVAL;
     }
 
+  /* Errata 16: SGMII registers are not initialized by hardware reset
+   * To ensure clean environment, reset the switch now.
+   */
+
+  regval16 = SGMII_CONTROL_SOFT_RESET;
+  ret = ksz9477_sgmii_write_indirect(KSZ9477_SGMII_CONTROL,
+                                     &regval16, 1);
+
   /* Check that indirect access to PHY MMD works.
    * Write LED mode to single-LED mode and verify access by
    * reading back the value.
diff --git a/drivers/net/ksz9477_reg.h b/drivers/net/ksz9477_reg.h
index 001a78a0e90..142a1e4590b 100644
--- a/drivers/net/ksz9477_reg.h
+++ b/drivers/net/ksz9477_reg.h
@@ -100,6 +100,10 @@
 
 /* Register bit definitions */
 
+/* KSZ9477_SGMII_CONTROL */
+
+#define SGMII_CONTROL_SOFT_RESET          (1 << 15)
+
 /* KSZ9477_ID2, KSZ9477_ID1 */
 
 #define KSZ9477_ID                         0x9477