hwmon: Support for Dallas Semiconductor DS620 (60994698) · Commits · e / devices / android_kernel_xiaomi_markw

Documentation/hwmon/ds620

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		Kernel driver ds620
		===================

		Supported chips:
		* Dallas Semiconductor DS620
		Prefix: 'ds620'
		Datasheet: Publicly available at the Dallas Semiconductor website
		http://www.dalsemi.com/

		Authors:
		Roland Stigge <stigge@antcom.de>
		based on ds1621.c by
		Christian W. Zuckschwerdt <zany@triq.net>

		Description
		-----------

		The DS620 is a (one instance) digital thermometer and thermostat. It has both
		high and low temperature limits which can be user defined (i.e. programmed
		into non-volatile on-chip registers). Temperature range is -55 degree Celsius
		to +125. Between 0 and 70 degree Celsius, accuracy is 0.5 Kelvin. The value
		returned via sysfs displays post decimal positions.

		The thermostat function works as follows: When configured via platform_data
		(struct ds620_platform_data) .pomode == 0 (default), the thermostat output pin
		PO is always low. If .pomode == 1, the thermostat is in PO_LOW mode. I.e., the
		output pin PO becomes active when the temperature falls below temp1_min and
		stays active until the temperature goes above temp1_max.

		Likewise, with .pomode == 2, the thermostat is in PO_HIGH mode. I.e., the PO
		output pin becomes active when the temperature goes above temp1_max and stays
		active until the temperature falls below temp1_min.

		The PO output pin of the DS620 operates active-low.

drivers/hwmon/Kconfig

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		@@ -274,6 +274,16 @@ config SENSORS_ATXP1
		This driver can also be built as a module. If so, the module
		will be called atxp1.

		config SENSORS_DS620
		tristate "Dallas Semiconductor DS620"
		depends on I2C
		help
		If you say yes here you get support for Dallas Semiconductor
		DS620 sensor chip.

		This driver can also be built as a module. If so, the module
		will be called ds620.

		config SENSORS_DS1621
		tristate "Dallas Semiconductor DS1621 and DS1625"
		depends on I2C

drivers/hwmon/Makefile

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		@@ -41,6 +41,7 @@ obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
		obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
		obj-$(CONFIG_SENSORS_PKGTEMP) += pkgtemp.o
		obj-$(CONFIG_SENSORS_DME1737) += dme1737.o
		obj-$(CONFIG_SENSORS_DS620) += ds620.o
		obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
		obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o
		obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o

drivers/hwmon/ds620.c

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		/*
		* ds620.c - Support for temperature sensor and thermostat DS620
		*
		* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
		*
		* based on ds1621.c by Christian W. Zuckschwerdt <zany@triq.net>
		*
		* 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.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program; if not, write to the Free Software
		* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
		*/

		#include <linux/module.h>
		#include <linux/init.h>
		#include <linux/slab.h>
		#include <linux/jiffies.h>
		#include <linux/i2c.h>
		#include <linux/hwmon.h>
		#include <linux/hwmon-sysfs.h>
		#include <linux/err.h>
		#include <linux/mutex.h>
		#include <linux/sysfs.h>
		#include <linux/i2c/ds620.h>

		/*
		* Many DS620 constants specified below
		* 15 14 13 12 11 10 09 08
		* \|Done\|NVB \|THF \|TLF \|R1 \|R0 \|AUTOC\|1SHOT\|
		*
		* 07 06 05 04 03 02 01 00
		* \|PO2 \|PO1 \|A2 \|A1 \|A0 \| \| \| \|
		*/
		#define DS620_REG_CONFIG_DONE 0x8000
		#define DS620_REG_CONFIG_NVB 0x4000
		#define DS620_REG_CONFIG_THF 0x2000
		#define DS620_REG_CONFIG_TLF 0x1000
		#define DS620_REG_CONFIG_R1 0x0800
		#define DS620_REG_CONFIG_R0 0x0400
		#define DS620_REG_CONFIG_AUTOC 0x0200
		#define DS620_REG_CONFIG_1SHOT 0x0100
		#define DS620_REG_CONFIG_PO2 0x0080
		#define DS620_REG_CONFIG_PO1 0x0040
		#define DS620_REG_CONFIG_A2 0x0020
		#define DS620_REG_CONFIG_A1 0x0010
		#define DS620_REG_CONFIG_A0 0x0008

		/* The DS620 registers */
		static const u8 DS620_REG_TEMP[3] = {
		0xAA, /* input, word, RO */
		0xA2, /* min, word, RW */
		0xA0, /* max, word, RW */
		};

		#define DS620_REG_CONF 0xAC /* word, RW */
		#define DS620_COM_START 0x51 /* no data */
		#define DS620_COM_STOP 0x22 /* no data */

		/* Each client has this additional data */
		struct ds620_data {
		struct device *hwmon_dev;
		struct mutex update_lock;
		char valid; /* !=0 if following fields are valid */
		unsigned long last_updated; /* In jiffies */

		u16 temp[3]; /* Register values, word */
		};

		/*
		* Temperature registers are word-sized.
		* DS620 uses a high-byte first convention, which is exactly opposite to
		* the SMBus standard.
		*/
		static int ds620_read_temp(struct i2c_client *client, u8 reg)
		{
		int ret;

		ret = i2c_smbus_read_word_data(client, reg);
		if (ret < 0)
		return ret;
		return swab16(ret);
		}

		static int ds620_write_temp(struct i2c_client *client, u8 reg, u16 value)
		{
		return i2c_smbus_write_word_data(client, reg, swab16(value));
		}

		static void ds620_init_client(struct i2c_client *client)
		{
		struct ds620_platform_data *ds620_info = client->dev.platform_data;
		u16 conf, new_conf;

		new_conf = conf =
		swab16(i2c_smbus_read_word_data(client, DS620_REG_CONF));

		/* switch to continuous conversion mode */
		new_conf &= ~DS620_REG_CONFIG_1SHOT;
		/* already high at power-on, but don't trust the BIOS! */
		new_conf \|= DS620_REG_CONFIG_PO2;
		/* thermostat mode according to platform data */
		if (ds620_info && ds620_info->pomode == 1)
		new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
		else if (ds620_info && ds620_info->pomode == 2)
		new_conf \|= DS620_REG_CONFIG_PO1; /* PO_HIGH */
		else
		new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
		/* with highest precision */
		new_conf \|= DS620_REG_CONFIG_R1 \| DS620_REG_CONFIG_R0;

		if (conf != new_conf)
		i2c_smbus_write_word_data(client, DS620_REG_CONF,
		swab16(new_conf));

		/* start conversion */
		i2c_smbus_write_byte(client, DS620_COM_START);
		}

		static struct ds620_data ds620_update_client(struct device dev)
		{
		struct i2c_client *client = to_i2c_client(dev);
		struct ds620_data *data = i2c_get_clientdata(client);
		struct ds620_data *ret = data;

		mutex_lock(&data->update_lock);

		if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
		\|\| !data->valid) {
		int i;
		int res;

		dev_dbg(&client->dev, "Starting ds620 update\n");

		for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
		res = ds620_read_temp(client,
		DS620_REG_TEMP[i]);
		if (res < 0) {
		ret = ERR_PTR(res);
		goto abort;
		}

		data->temp[i] = res;
		}

		data->last_updated = jiffies;
		data->valid = 1;
		}
		abort:
		mutex_unlock(&data->update_lock);

		return ret;
		}

		static ssize_t show_temp(struct device dev, struct device_attribute da,
		char *buf)
		{
		struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
		struct ds620_data *data = ds620_update_client(dev);

		if (IS_ERR(data))
		return PTR_ERR(data);

		return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
		}

		static ssize_t set_temp(struct device dev, struct device_attribute da,
		const char *buf, size_t count)
		{
		int res;
		long val;

		struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
		struct i2c_client *client = to_i2c_client(dev);
		struct ds620_data *data = i2c_get_clientdata(client);

		res = strict_strtol(buf, 10, &val);

		if (res)
		return res;

		val = (val * 10 / 625) * 8;

		mutex_lock(&data->update_lock);
		data->temp[attr->index] = val;
		ds620_write_temp(client, DS620_REG_TEMP[attr->index],
		data->temp[attr->index]);
		mutex_unlock(&data->update_lock);
		return count;
		}

		static ssize_t show_alarm(struct device dev, struct device_attribute da,
		char *buf)
		{
		struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
		struct ds620_data *data = ds620_update_client(dev);
		struct i2c_client *client = to_i2c_client(dev);
		u16 conf, new_conf;
		int res;

		if (IS_ERR(data))
		return PTR_ERR(data);

		/* reset alarms if necessary */
		res = i2c_smbus_read_word_data(client, DS620_REG_CONF);
		if (res < 0)
		return res;

		conf = swab16(res);
		new_conf = conf;
		new_conf &= ~attr->index;
		if (conf != new_conf) {
		res = i2c_smbus_write_word_data(client, DS620_REG_CONF,
		swab16(new_conf));
		if (res < 0)
		return res;
		}

		return sprintf(buf, "%d\n", !!(conf & attr->index));
		}

		static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
		static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR \| S_IRUGO, show_temp, set_temp, 1);
		static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR \| S_IRUGO, show_temp, set_temp, 2);
		static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
		DS620_REG_CONFIG_TLF);
		static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
		DS620_REG_CONFIG_THF);

		static struct attribute *ds620_attributes[] = {
		&sensor_dev_attr_temp1_input.dev_attr.attr,
		&sensor_dev_attr_temp1_min.dev_attr.attr,
		&sensor_dev_attr_temp1_max.dev_attr.attr,
		&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
		&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
		NULL
		};

		static const struct attribute_group ds620_group = {
		.attrs = ds620_attributes,
		};

		static int ds620_probe(struct i2c_client *client,
		const struct i2c_device_id *id)
		{
		struct ds620_data *data;
		int err;

		data = kzalloc(sizeof(struct ds620_data), GFP_KERNEL);
		if (!data) {
		err = -ENOMEM;
		goto exit;
		}

		i2c_set_clientdata(client, data);
		mutex_init(&data->update_lock);

		/* Initialize the DS620 chip */
		ds620_init_client(client);

		/* Register sysfs hooks */
		err = sysfs_create_group(&client->dev.kobj, &ds620_group);
		if (err)
		goto exit_free;

		data->hwmon_dev = hwmon_device_register(&client->dev);
		if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove_files;
		}

		dev_info(&client->dev, "temperature sensor found\n");

		return 0;

		exit_remove_files:
		sysfs_remove_group(&client->dev.kobj, &ds620_group);
		exit_free:
		kfree(data);
		exit:
		return err;
		}

		static int ds620_remove(struct i2c_client *client)
		{
		struct ds620_data *data = i2c_get_clientdata(client);

		hwmon_device_unregister(data->hwmon_dev);
		sysfs_remove_group(&client->dev.kobj, &ds620_group);

		kfree(data);

		return 0;
		}

		static const struct i2c_device_id ds620_id[] = {
		{"ds620", 0},
		{}
		};

		MODULE_DEVICE_TABLE(i2c, ds620_id);

		/* This is the driver that will be inserted */
		static struct i2c_driver ds620_driver = {
		.class = I2C_CLASS_HWMON,
		.driver = {
		.name = "ds620",
		},
		.probe = ds620_probe,
		.remove = ds620_remove,
		.id_table = ds620_id,
		};

		static int __init ds620_init(void)
		{
		return i2c_add_driver(&ds620_driver);
		}

		static void __exit ds620_exit(void)
		{
		i2c_del_driver(&ds620_driver);
		}

		MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
		MODULE_DESCRIPTION("DS620 driver");
		MODULE_LICENSE("GPL");

		module_init(ds620_init);
		module_exit(ds620_exit);

include/linux/i2c/ds620.h

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		#ifndef _LINUX_DS620_H
		#define _LINUX_DS620_H

		#include <linux/types.h>
		#include <linux/i2c.h>

		/* platform data for the DS620 temperature sensor and thermostat */

		struct ds620_platform_data {
		/*
		* Thermostat output pin PO mode:
		* 0 = always low (default)
		* 1 = PO_LOW
		* 2 = PO_HIGH
		*
		* (see Documentation/hwmon/ds620)
		*/
		int pomode;
		};

		#endif /* _LINUX_DS620_H */