hwmon: (pmbus) Add tps40422 front-end driver

For TI power management chip TPS40422, READ_TEMPERATURE_2 command is supported on
page 1 of the chip, but the original driver(pmbus.c) only tried to detect this command
on page 0, this will lead to a result that the temperature sensor in page 1 couldn't
be detected. This change is to isolate the tps40422 driver from pmbus.c into a solo
front-end driver.

Signed-off-by: Zhu Laiwen <richard.zhu@nsn.com>
[Guenter Roeck: Dropped unnecessary license text (fixes checkpatch warning)]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/tps40422.c

@@ -0,0 +1,64 @@
+/*
+ * Hardware monitoring driver for TI TPS40422
+ *
+ * Copyright (c) 2014 Nokia Solutions and Networks.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+static struct pmbus_driver_info tps40422_info = {
+	.pages = 2,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_TEMP2
+		| PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_TEMP
+		| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
+	.func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_TEMP2
+		| PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_TEMP
+		| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
+};
+
+static int tps40422_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	return pmbus_do_probe(client, id, &tps40422_info);
+}
+
+static const struct i2c_device_id tps40422_id[] = {
+	{"tps40422", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, tps40422_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver tps40422_driver = {
+	.driver = {
+		   .name = "tps40422",
+		   },
+	.probe = tps40422_probe,
+	.remove = pmbus_do_remove,
+	.id_table = tps40422_id,
+};
+
+module_i2c_driver(tps40422_driver);
+
+MODULE_AUTHOR("Zhu Laiwen <richard.zhu@nsn.com>");
+MODULE_DESCRIPTION("PMBus driver for TI TPS40422");
+MODULE_LICENSE("GPL");