hwmon: Versatile Express hwmon driver

Versatile Express hwmon sensors

-------------------------------

Requires node properties:

- "compatible" value : one of

	"arm,vexpress-volt"

	"arm,vexpress-amp"

	"arm,vexpress-temp"

	"arm,vexpress-power"

	"arm,vexpress-energy"

- "arm,vexpress-sysreg,func" when controlled via vexpress-sysreg

  (see Documentation/devicetree/bindings/arm/vexpress-sysreg.txt

  for more details)

Optional node properties:

- label : string describing the monitored value

Example:

	energy@0 {

		compatible = "arm,vexpress-energy";

		arm,vexpress-sysreg,func = <13 0>;

		label = "A15 Jcore";

	};

Kernel driver vexpress

======================

Supported systems:

  * ARM Ltd. Versatile Express platform

    Prefix: 'vexpress'

    Datasheets:

      * "Hardware Description" sections of the Technical Reference Manuals

        for the Versatile Express boards:

        http://infocenter.arm.com/help/topic/com.arm.doc.subset.boards.express/index.html

      * Section "4.4.14. System Configuration registers" of the V2M-P1 TRM:

        http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0447-/index.html

Author: Pawel Moll

Description

-----------

Versatile Express platform (http://www.arm.com/versatileexpress/) is a

reference & prototyping system for ARM Ltd. processors. It can be set up

from a wide range of boards, each of them containing (apart of the main

chip/FPGA) a number of microcontrollers responsible for platform

configuration and control. Theses microcontrollers can also monitor the

board and its environment by a number of internal and external sensors,

providing information about power lines voltages and currents, board

temperature and power usage. Some of them also calculate consumed energy

and provide a cumulative use counter.

The configuration devices are _not_ memory mapped and must be accessed

via a custom interface, abstracted by the "vexpress_config" API.

As these devices are non-discoverable, they must be described in a Device

Tree passed to the kernel. Details of the DT binding for them can be found

in Documentation/devicetree/bindings/hwmon/vexpress.txt.

	This driver can also be built as a module. If so it will be called

	twl4030-madc-hwmon.

config SENSORS_VEXPRESS

	tristate "Versatile Express"

	depends on VEXPRESS_CONFIG

	help

	  This driver provides support for hardware sensors available on

	  the ARM Ltd's Versatile Express platform. It can provide wide

	  range of information like temperature, power, energy.

config SENSORS_VIA_CPUTEMP

	tristate "VIA CPU temperature sensor"

	depends on X86

obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o

obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o

obj-$(CONFIG_SENSORS_TWL4030_MADC)+= twl4030-madc-hwmon.o

obj-$(CONFIG_SENSORS_VEXPRESS)	+= vexpress.o

obj-$(CONFIG_SENSORS_VIA_CPUTEMP)+= via-cputemp.o

obj-$(CONFIG_SENSORS_VIA686A)	+= via686a.o

obj-$(CONFIG_SENSORS_VT1211)	+= vt1211.o

/*

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * 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.

 *

 * Copyright (C) 2012 ARM Limited

 */

#define DRVNAME "vexpress-hwmon"

#define pr_fmt(fmt) DRVNAME ": " fmt

#include <linux/device.h>

#include <linux/err.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/vexpress.h>

struct vexpress_hwmon_data {

	struct device *hwmon_dev;

	struct vexpress_config_func *func;

};

static ssize_t vexpress_hwmon_name_show(struct device *dev,

		struct device_attribute *dev_attr, char *buffer)

{

	const char *compatible = of_get_property(dev->of_node, "compatible",

			NULL);

	return sprintf(buffer, "%s\n", compatible);

}

static ssize_t vexpress_hwmon_label_show(struct device *dev,

		struct device_attribute *dev_attr, char *buffer)

{

	const char *label = of_get_property(dev->of_node, "label", NULL);

	if (!label)

		return -ENOENT;

	return snprintf(buffer, PAGE_SIZE, "%s\n", label);

}

static ssize_t vexpress_hwmon_u32_show(struct device *dev,

		struct device_attribute *dev_attr, char *buffer)

{

	struct vexpress_hwmon_data *data = dev_get_drvdata(dev);

	int err;

	u32 value;

	err = vexpress_config_read(data->func, 0, &value);

	if (err)

		return err;

	return snprintf(buffer, PAGE_SIZE, "%u\n", value /

			to_sensor_dev_attr(dev_attr)->index);

}

static ssize_t vexpress_hwmon_u64_show(struct device *dev,

		struct device_attribute *dev_attr, char *buffer)

{

	struct vexpress_hwmon_data *data = dev_get_drvdata(dev);

	int err;

	u32 value_hi, value_lo;

	err = vexpress_config_read(data->func, 0, &value_lo);

	if (err)

		return err;

	err = vexpress_config_read(data->func, 1, &value_hi);

	if (err)

		return err;

	return snprintf(buffer, PAGE_SIZE, "%llu\n",

			div_u64(((u64)value_hi << 32) | value_lo,

			to_sensor_dev_attr(dev_attr)->index));

}

static DEVICE_ATTR(name, S_IRUGO, vexpress_hwmon_name_show, NULL);

#define VEXPRESS_HWMON_ATTRS(_name, _label_attr, _input_attr)	\

struct attribute *vexpress_hwmon_attrs_##_name[] = {		\

	&dev_attr_name.attr,					\

	&dev_attr_##_label_attr.attr,				\

	&sensor_dev_attr_##_input_attr.dev_attr.attr,		\

	NULL							\

}

#if !defined(CONFIG_REGULATOR_VEXPRESS)

static DEVICE_ATTR(in1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);

static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, vexpress_hwmon_u32_show,

		NULL, 1000);

static VEXPRESS_HWMON_ATTRS(volt, in1_label, in1_input);

static struct attribute_group vexpress_hwmon_group_volt = {

	.attrs = vexpress_hwmon_attrs_volt,

};

#endif

static DEVICE_ATTR(curr1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);

static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, vexpress_hwmon_u32_show,

		NULL, 1000);

static VEXPRESS_HWMON_ATTRS(amp, curr1_label, curr1_input);

static struct attribute_group vexpress_hwmon_group_amp = {

	.attrs = vexpress_hwmon_attrs_amp,

};

static DEVICE_ATTR(temp1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, vexpress_hwmon_u32_show,

		NULL, 1000);

static VEXPRESS_HWMON_ATTRS(temp, temp1_label, temp1_input);

static struct attribute_group vexpress_hwmon_group_temp = {

	.attrs = vexpress_hwmon_attrs_temp,

};

static DEVICE_ATTR(power1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);

static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, vexpress_hwmon_u32_show,

		NULL, 1);

static VEXPRESS_HWMON_ATTRS(power, power1_label, power1_input);

static struct attribute_group vexpress_hwmon_group_power = {

	.attrs = vexpress_hwmon_attrs_power,

};

static DEVICE_ATTR(energy1_label, S_IRUGO, vexpress_hwmon_label_show, NULL);

static SENSOR_DEVICE_ATTR(energy1_input, S_IRUGO, vexpress_hwmon_u64_show,

		NULL, 1);

static VEXPRESS_HWMON_ATTRS(energy, energy1_label, energy1_input);

static struct attribute_group vexpress_hwmon_group_energy = {

	.attrs = vexpress_hwmon_attrs_energy,

};

static struct of_device_id vexpress_hwmon_of_match[] = {

#if !defined(CONFIG_REGULATOR_VEXPRESS)

	{

		.compatible = "arm,vexpress-volt",

		.data = &vexpress_hwmon_group_volt,

	},

#endif

	{

		.compatible = "arm,vexpress-amp",

		.data = &vexpress_hwmon_group_amp,

	}, {

		.compatible = "arm,vexpress-temp",

		.data = &vexpress_hwmon_group_temp,

	}, {

		.compatible = "arm,vexpress-power",

		.data = &vexpress_hwmon_group_power,

	}, {

		.compatible = "arm,vexpress-energy",

		.data = &vexpress_hwmon_group_energy,

	},

	{}

};

MODULE_DEVICE_TABLE(of, vexpress_hwmon_of_match);

static int vexpress_hwmon_probe(struct platform_device *pdev)

{

	int err;

	const struct of_device_id *match;

	struct vexpress_hwmon_data *data;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;

	platform_set_drvdata(pdev, data);

	match = of_match_device(vexpress_hwmon_of_match, &pdev->dev);

	if (!match)

		return -ENODEV;

	data->func = vexpress_config_func_get_by_dev(&pdev->dev);

	if (!data->func)

		return -ENODEV;

	err = sysfs_create_group(&pdev->dev.kobj, match->data);

	if (err)

		goto error;

	data->hwmon_dev = hwmon_device_register(&pdev->dev);

	if (IS_ERR(data->hwmon_dev)) {

		err = PTR_ERR(data->hwmon_dev);

		goto error;

	}

	return 0;

error:

	sysfs_remove_group(&pdev->dev.kobj, match->data);

	vexpress_config_func_put(data->func);

	return err;

}

static int __devexit vexpress_hwmon_remove(struct platform_device *pdev)

{

	struct vexpress_hwmon_data *data = platform_get_drvdata(pdev);

	const struct of_device_id *match;

	hwmon_device_unregister(data->hwmon_dev);

	match = of_match_device(vexpress_hwmon_of_match, &pdev->dev);

	sysfs_remove_group(&pdev->dev.kobj, match->data);

	vexpress_config_func_put(data->func);

	return 0;

}

static struct platform_driver vexpress_hwmon_driver = {

	.probe = vexpress_hwmon_probe,

	.remove = __devexit_p(vexpress_hwmon_remove),

	.driver	= {

		.name = DRVNAME,

		.owner = THIS_MODULE,

		.of_match_table = vexpress_hwmon_of_match,

	},

};

module_platform_driver(vexpress_hwmon_driver);

MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");

MODULE_DESCRIPTION("Versatile Express hwmon sensors driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:vexpress-hwmon");