4 files changed, 106 insertions, 0 deletions
diff --git a/lib/utils/regmap/Kconfig b/lib/utils/regmap/Kconfig
index 8db5c8b8..b1ff501b 100644
--- a/lib/utils/regmap/Kconfig
+++ b/lib/utils/regmap/Kconfig
@@ -2,6 +2,12 @@
 
 menu "Regmap Support"
 
+config FDT_REGMAP
+	bool "FDT based regmap drivers"
+	depends on FDT
+	select REGMAP
+	default n
+
 config REGMAP
 	bool "Regmap support"
 	default n
diff --git a/lib/utils/regmap/fdt_regmap.c b/lib/utils/regmap/fdt_regmap.c
new file mode 100644
index 00000000..fffac1de
--- /dev/null
+++ b/lib/utils/regmap/fdt_regmap.c
@@ -0,0 +1,94 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ *
+ * Authors:
+ *   Anup Patel <[email protected]>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_error.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/regmap/fdt_regmap.h>
+
+/* List of FDT regmap drivers generated at compile time */
+extern struct fdt_regmap *fdt_regmap_drivers[];
+extern unsigned long fdt_regmap_drivers_size;
+
+static int fdt_regmap_init(void *fdt, int nodeoff, u32 phandle)
+{
+	int pos, rc;
+	struct fdt_regmap *drv;
+	const struct fdt_match *match;
+
+	/* Try all I2C drivers one-by-one */
+	for (pos = 0; pos < fdt_regmap_drivers_size; pos++) {
+		drv = fdt_regmap_drivers[pos];
+		match = fdt_match_node(fdt, nodeoff, drv->match_table);
+		if (match && drv->init) {
+			rc = drv->init(fdt, nodeoff, phandle, match);
+			if (rc == SBI_ENODEV)
+				continue;
+			if (rc)
+				return rc;
+			return 0;
+		}
+	}
+
+	return SBI_ENOSYS;
+}
+
+static int fdt_regmap_find(void *fdt, int nodeoff, u32 phandle,
+			   struct regmap **out_rmap)
+{
+	int rc;
+	struct regmap *rmap = regmap_find(phandle);
+
+	if (!rmap) {
+		/* Regmap not found so initialize matching driver */
+		rc = fdt_regmap_init(fdt, nodeoff, phandle);
+		if (rc)
+			return rc;
+
+		/* Try to find regmap again */
+		rmap = regmap_find(phandle);
+		if (!rmap)
+			return SBI_ENOSYS;
+	}
+
+	if (out_rmap)
+		*out_rmap = rmap;
+
+	return 0;
+}
+
+int fdt_regmap_get_by_phandle(void *fdt, u32 phandle,
+			      struct regmap **out_rmap)
+{
+	int pnodeoff;
+
+	if (!fdt || !out_rmap)
+		return SBI_EINVAL;
+
+	pnodeoff = fdt_node_offset_by_phandle(fdt, phandle);
+	if (pnodeoff < 0)
+		return pnodeoff;
+
+	return fdt_regmap_find(fdt, pnodeoff, phandle, out_rmap);
+}
+
+int fdt_regmap_get(void *fdt, int nodeoff, struct regmap **out_rmap)
+{
+	int len;
+	const fdt32_t *val;
+
+	if (!fdt || (nodeoff < 0) || !out_rmap)
+		return SBI_EINVAL;
+
+	val = fdt_getprop(fdt, nodeoff, "regmap", &len);
+	if (!val)
+		return SBI_ENOENT;
+
+	return fdt_regmap_get_by_phandle(fdt, fdt32_to_cpu(*val), out_rmap);
+}
diff --git a/lib/utils/regmap/fdt_regmap_drivers.carray b/lib/utils/regmap/fdt_regmap_drivers.carray
new file mode 100644
index 00000000..c2f1c9d0
--- /dev/null
+++ b/lib/utils/regmap/fdt_regmap_drivers.carray
@@ -0,0 +1,3 @@
+HEADER: sbi_utils/regmap/fdt_regmap.h
+TYPE: struct fdt_regmap
+NAME: fdt_regmap_drivers
diff --git a/lib/utils/regmap/objects.mk b/lib/utils/regmap/objects.mk
index 5d1bead0..5ce2373e 100644
--- a/lib/utils/regmap/objects.mk
+++ b/lib/utils/regmap/objects.mk
@@ -7,4 +7,7 @@
 #   Anup Patel <[email protected]>
 #
 
+libsbiutils-objs-$(CONFIG_FDT_REGMAP) += regmap/fdt_regmap.o
+libsbiutils-objs-$(CONFIG_FDT_REGMAP) += regmap/fdt_regmap_drivers.o
+
 libsbiutils-objs-$(CONFIG_REGMAP) += regmap/regmap.o