power: pmic: add the base TPS80031 PMIC support

Add support to bind the regulators/child nodes with the pmic.
Also adds the pmic i2c based read/write functions to access pmic
registers.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/power/pmic/tps80031.c b/drivers/power/pmic/tps80031.c
new file mode 100644
index 0000000..6b36ebb
--- /dev/null
+++ b/drivers/power/pmic/tps80031.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Copyright(C) 2023 Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <dm.h>
+#include <dm/lists.h>
+#include <power/pmic.h>
+#include <power/tps80031.h>
+
+static const struct pmic_child_info pmic_children_info[] = {
+	{ .prefix = "ldo", .driver = TPS80031_LDO_DRIVER },
+	{ .prefix = "smps", .driver = TPS80031_SMPS_DRIVER },
+	{ },
+};
+
+static int tps80031_write(struct udevice *dev, uint reg, const uint8_t *buff,
+			  int len)
+{
+	int ret;
+
+	ret = dm_i2c_write(dev, reg, buff, len);
+	if (ret) {
+		log_debug("write error to device: %p register: %#x!\n", dev, reg);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tps80031_read(struct udevice *dev, uint reg, uint8_t *buff, int len)
+{
+	int ret;
+
+	ret = dm_i2c_read(dev, reg, buff, len);
+	if (ret) {
+		log_debug("read error from device: %p register: %#x!\n", dev, reg);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tps80031_bind(struct udevice *dev)
+{
+	ofnode regulators_node;
+	int children;
+
+	regulators_node = dev_read_subnode(dev, "regulators");
+	if (!ofnode_valid(regulators_node)) {
+		log_err("%s regulators subnode not found!\n", dev->name);
+		return -ENXIO;
+	}
+
+	debug("%s: '%s' - found regulators subnode\n", __func__, dev->name);
+
+	children = pmic_bind_children(dev, regulators_node, pmic_children_info);
+	if (!children)
+		log_err("%s - no child found\n", dev->name);
+
+	/* Always return success for this device */
+	return 0;
+}
+
+static struct dm_pmic_ops tps80031_ops = {
+	.read = tps80031_read,
+	.write = tps80031_write,
+};
+
+static const struct udevice_id tps80031_ids[] = {
+	{ .compatible = "ti,tps80031" },
+	{ .compatible = "ti,tps80032" },
+	{ }
+};
+
+U_BOOT_DRIVER(pmic_tps80031) = {
+	.name = "tps80031_pmic",
+	.id = UCLASS_PMIC,
+	.of_match = tps80031_ids,
+	.bind = tps80031_bind,
+	.ops = &tps80031_ops,
+};