hwmon: Add driver for MPS MPQ8785 Synchronous Step-Down Converter

Add support for mpq8785 device from Monolithic Power Systems, Inc.
(MPS) vendor. This is synchronous step-down controller.

Signed-off-by: Charles Hsu <ythsu0511@gmail.com>
Link: https://lore.kernel.org/r/20240131074822.2962078-2-ythsu0511@gmail.com
[groeck: probe_new --> probe; add MODULE_IMPORT_NS(PMBUS)]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 90 insertions, 0 deletions

diff --git a/drivers/hwmon/pmbus/mpq8785.c b/drivers/hwmon/pmbus/mpq8785.c
new file mode 100644
index 000000000000..4e2549cc8120
--- /dev/null
+++ b/drivers/hwmon/pmbus/mpq8785.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MPS MPQ8785 Step-Down Converter
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include "pmbus.h"
+
+static int mpq8785_identify(struct i2c_client *client,
+			    struct pmbus_driver_info *info)
+{
+	int vout_mode;
+
+	vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
+	if (vout_mode < 0 || vout_mode == 0xff)
+		return vout_mode < 0 ? vout_mode : -ENODEV;
+	switch (vout_mode >> 5) {
+	case 0:
+		info->format[PSC_VOLTAGE_OUT] = linear;
+		break;
+	case 1:
+	case 2:
+		info->format[PSC_VOLTAGE_OUT] = direct,
+		info->m[PSC_VOLTAGE_OUT] = 64;
+		info->b[PSC_VOLTAGE_OUT] = 0;
+		info->R[PSC_VOLTAGE_OUT] = 1;
+		break;
+	default:
+		return -ENODEV;
+	}
+
+	return 0;
+};
+
+static struct pmbus_driver_info mpq8785_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = direct,
+	.format[PSC_CURRENT_OUT] = direct,
+	.format[PSC_TEMPERATURE] = direct,
+	.m[PSC_VOLTAGE_IN] = 4,
+	.b[PSC_VOLTAGE_IN] = 0,
+	.R[PSC_VOLTAGE_IN] = 1,
+	.m[PSC_CURRENT_OUT] = 16,
+	.b[PSC_CURRENT_OUT] = 0,
+	.R[PSC_CURRENT_OUT] = 0,
+	.m[PSC_TEMPERATURE] = 1,
+	.b[PSC_TEMPERATURE] = 0,
+	.R[PSC_TEMPERATURE] = 0,
+	.func[0] =
+		PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
+		PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+	.identify = mpq8785_identify,
+};
+
+static int mpq8785_probe(struct i2c_client *client)
+{
+	return pmbus_do_probe(client, &mpq8785_info);
+};
+
+static const struct i2c_device_id mpq8785_id[] = {
+	{ "mpq8785", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, mpq8785_id);
+
+static const struct of_device_id __maybe_unused mpq8785_of_match[] = {
+	{ .compatible = "mps,mpq8785" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mpq8785_of_match);
+
+static struct i2c_driver mpq8785_driver = {
+	.driver = {
+		   .name = "mpq8785",
+		   .of_match_table = of_match_ptr(mpq8785_of_match),
+	},
+	.probe = mpq8785_probe,
+	.id_table = mpq8785_id,
+};
+
+module_i2c_driver(mpq8785_driver);
+
+MODULE_AUTHOR("Charles Hsu <ythsu0511@gmail.com>");
+MODULE_DESCRIPTION("PMBus driver for MPS MPQ8785");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);