mt7621-qtn-rgmii: enable RGMII connected Quantenna QV840

Write a magic value to a magic destination.  This might
be specific to the Mitrastar designed ZyXEL WAP6805.

Signed-off-by: Bjørn Mork <bjorn@mork.no>

1 files changed, 48 insertions, 0 deletions

diff --git a/package/kernel/mt7621-qtn-rgmii/src/mt7621-qtn-rgmii.c b/package/kernel/mt7621-qtn-rgmii/src/mt7621-qtn-rgmii.c
new file mode 100644
index 0000000000..5f223b5d75
--- /dev/null
+++ b/package/kernel/mt7621-qtn-rgmii/src/mt7621-qtn-rgmii.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020  Bjørn Mork <bjorn@mork.no>
+ */
+#include <linux/io.h>
+#include <linux/module.h>
+
+#define MODULE_NAME "mt7621-qtn-rgmii"
+#define RGMII_REG_BASE	0x1e110008
+#define RGMII_REG_SIZE	4
+#define RGMII_REG_VALUE	0x9000c
+
+static u32 oldval;
+
+static int __init mt7621_qtn_rgmii_init(void)
+{
+	void __iomem *base = ioremap(RGMII_REG_BASE, RGMII_REG_SIZE);
+
+	if (!base)
+		return -ENOMEM;
+	oldval = ioread32(base);
+	if (oldval != RGMII_REG_VALUE) {
+		iowrite32(RGMII_REG_VALUE, base);
+		pr_info(MODULE_NAME ": changed register 0x%08x value from 0x%08x to 0x%08x\n", RGMII_REG_BASE, oldval,  RGMII_REG_VALUE);
+	}
+	iounmap(base);
+	return 0;
+}
+
+static void __exit mt7621_qtn_rgmii_exit(void)
+{
+	void __iomem *base = ioremap(RGMII_REG_BASE, RGMII_REG_SIZE);
+
+	if (!base)
+		return;
+	if (oldval != RGMII_REG_VALUE) {
+		iowrite32(oldval, base);
+		pr_info(MODULE_NAME ": reset register 0x%08x back to 0x%08x\n", RGMII_REG_BASE, oldval);
+	}
+	iounmap(base);
+}
+
+module_init(mt7621_qtn_rgmii_init);
+module_exit(mt7621_qtn_rgmii_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bjørn Mork <bjorn@mork.no>");
+MODULE_DESCRIPTION("Enable RGMII connected Quantenna module on MT7621");