pmic: Add Renesas RAA215300 PMIC driver

The RZ/G2L SMARC module is powered via a Renesas RAA215300 PMIC which
provides several voltage converters, a real time clock (RTC) and reset
control. A basic driver is implemented for this device so that we can
read, write and dump the PMIC registers.

The raa215300_bind() function is added as a stub, binding of the
sysreset driver will be added in a later patch.

Additional features of this PMIC (such as reset control) may be
supported by future patches.

Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/power/pmic/raa215300.c b/drivers/power/pmic/raa215300.c
new file mode 100644
index 0000000..b93a0d3
--- /dev/null
+++ b/drivers/power/pmic/raa215300.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Renesas Electronics Corporation
+ */
+
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <i2c.h>
+#include <power/pmic.h>
+
+#define RAA215300_REG_COUNT 0x80
+
+static int raa215300_reg_count(struct udevice *dev)
+{
+	return RAA215300_REG_COUNT;
+}
+
+static struct dm_pmic_ops raa215300_ops = {
+	.reg_count = raa215300_reg_count,
+	.read = dm_i2c_read,
+	.write = dm_i2c_write,
+};
+
+static const struct udevice_id raa215300_ids[] = {
+	{ .compatible = "renesas,raa215300" },
+	{ /* sentinel */ }
+};
+
+static int raa215300_bind(struct udevice *dev)
+{
+	return 0;
+}
+
+U_BOOT_DRIVER(raa215300_pmic) = {
+	.name = "raa215300_pmic",
+	.id = UCLASS_PMIC,
+	.of_match = raa215300_ids,
+	.bind = raa215300_bind,
+	.ops = &raa215300_ops,
+};