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 <[e-mail]>
[Guenter Roeck: Dropped unnecessary license text (fixes checkpatch warning)]
Signed-off-by: Guenter Roeck <[e-mail]>

Documentation/hwmon/pmbus

···
 	http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf
 	http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf
 	http://www.lineagepower.com/oem/pdf/MDT040A0X.pdf
-  * Texas Instruments TPS40400, TPS40422
-    Prefixes: 'tps40400', 'tps40422'
+  * Texas Instruments TPS40400
+    Prefixes: 'tps40400'
     Addresses scanned: -
     Datasheets:
 	http://www.ti.com/lit/gpn/tps40400
-	http://www.ti.com/lit/gpn/tps40422
   * Generic PMBus devices
     Prefix: 'pmbus'
     Addresses scanned: -

Documentation/hwmon/tps40422

···
+Kernel driver tps40422
+======================
+
+Supported chips:
+  * TI TPS40422
+    Prefix: 'tps40422'
+    Addresses scanned: -
+    Datasheet: http://www.ti.com/lit/gpn/tps40422
+
+Author: Zhu Laiwen <[e-mail]>
+
+
+Description
+-----------
+
+This driver supports TI TPS40422 Dual-Output or Two-Phase Synchronous Buck
+Controller with PMBus
+
+The driver is a client driver to the core PMBus driver.
+Please see Documentation/hwmon/pmbus for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices for
+details.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported.
+
+in[1-2]_label		"vout[1-2]"
+in[1-2]_input		Measured voltage. From READ_VOUT register.
+in[1-2]_alarm		voltage alarm.
+
+curr[1-2]_input		Measured current. From READ_IOUT register.
+curr[1-2]_label		"iout[1-2]"
+curr1_max		Maximum current. From IOUT_OC_WARN_LIMIT register.
+curr1_crit		Critical maximum current. From IOUT_OC_FAULT_LIMIT register.
+curr1_max_alarm		Current high alarm. From IOUT_OC_WARN_LIMIT status.
+curr1_crit_alarm	Current critical high alarm. From IOUT_OC_FAULT status.
+curr2_alarm		Current high alarm. From IOUT_OC_WARNING status.
+
+temp1_input		Measured temperature. From READ_TEMPERATURE_2 register on page 0.
+temp1_max		Maximum temperature. From OT_WARN_LIMIT register.
+temp1_crit		Critical high temperature. From OT_FAULT_LIMIT register.
+temp1_max_alarm		Chip temperature high alarm. Set by comparing
+			READ_TEMPERATURE_2 on page 0 with OT_WARN_LIMIT if TEMP_OT_WARNING
+			status is set.
+temp1_crit_alarm	Chip temperature critical high alarm. Set by comparing
+			READ_TEMPERATURE_2 on page 0 with OT_FAULT_LIMIT if TEMP_OT_FAULT
+			status is set.
+temp2_input		Measured temperature. From READ_TEMPERATURE_2 register on page 1.
+temp2_alarm		Chip temperature alarm on page 1.

drivers/hwmon/pmbus/Kconfig

···
 	help
 	  If you say yes here you get hardware monitoring support for generic
 	  PMBus devices, including but not limited to ADP4000, BMR453, BMR454,
-	  MDT040, NCP4200, NCP4208, PDT003, PDT006, PDT012, UDT020, TPS40400,
-	  and TPS40422.
+	  MDT040, NCP4200, NCP4208, PDT003, PDT006, PDT012, UDT020, and TPS40400.
 
 	  This driver can also be built as a module. If so, the module will
 	  be called pmbus.
···
 
 	  This driver can also be built as a module. If so, the module will
 	  be called max8688.
+
+config SENSORS_TPS40422
+	tristate "TI TPS40422"
+	default n
+	help
+	  If you say yes here you get hardware monitoring support for TI
+	  TPS40422.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called tps40422.
 
 config SENSORS_UCD9000
 	tristate "TI UCD90120, UCD90124, UCD9090, UCD90910"

drivers/hwmon/pmbus/Makefile

···
 obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
 obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
+obj-$(CONFIG_SENSORS_TPS40422)	+= tps40422.o
 obj-$(CONFIG_SENSORS_UCD9000)	+= ucd9000.o
 obj-$(CONFIG_SENSORS_UCD9200)	+= ucd9200.o
 obj-$(CONFIG_SENSORS_ZL6100)	+= zl6100.o

drivers/hwmon/pmbus/pmbus.c

···
 	{"pdt012", 1},
 	{"pmbus", 0},
 	{"tps40400", 1},
-	{"tps40422", 2},
 	{"udt020", 1},
 	{}
 };

drivers/hwmon/pmbus/tps40422.c

···
+/*
+ * 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 <[e-mail]>");
+MODULE_DESCRIPTION("PMBus driver for TI TPS40422");
+MODULE_LICENSE("GPL");