Date:	Tue, 5 Apr 2011 20:06:23 -0700
From:	<achew@...dia.com>
To:	<khali@...ux-fr.org>, <guenter.roeck@...csson.com>
CC:	<lm-sensors@...sensors.org>, <linux-kernel@...r.kernel.org>,
	<w30289@...orola.com>, <toddpoynor@...gle.com>, <wni@...dia.com>,
	<olofj@...omium.org>, Andrew Chew <achew@...dia.com>
Subject: [PATCH 1/1] [hwmon] nct1008: Initial NCT1008 driver

From: Andrew Chew <achew@...dia.com>

This is a digital temperature sensor I2C peripheral from ON Semiconductor.

Signed-off-by: Andrew Chew <achew@...dia.com>
---
 drivers/hwmon/Kconfig   |   11 ++
 drivers/hwmon/Makefile  |    1 +
 drivers/hwmon/nct1008.c |  423 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 435 insertions(+), 0 deletions(-)
 create mode 100644 drivers/hwmon/nct1008.c

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 060ef63..daa6159 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -738,6 +738,17 @@ config SENSORS_MAX6650
 	  This driver can also be built as a module.  If so, the module
 	  will be called max6650.
 
+config SENSORS_NCT1008
+	tristate "ON Semiconductor Temperature Sensor"
+	default n
+	depends on I2C
+	help
+	  Say yes here if you wish to include the ON Semiconductor
+	  NCT1008 Temperature sensor.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called nct1008.
+
 config SENSORS_PC87360
 	tristate "National Semiconductor PC87360 family"
 	select HWMON_VID
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 967d0ea..803893c 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o
 obj-$(CONFIG_SENSORS_MAX6639)	+= max6639.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
+obj-$(CONFIG_SENSORS_NCT1008)	+= nct1008.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
 obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
 obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
diff --git a/drivers/hwmon/nct1008.c b/drivers/hwmon/nct1008.c
new file mode 100644
index 0000000..ebae3b6
--- /dev/null
+++ b/drivers/hwmon/nct1008.c
@@ -0,0 +1,423 @@
+/*
+ * Driver for NCT1008, temperature monitoring device from ON Semiconductors
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+
+#include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+
+#include <linux/nct1008.h>
+#include <linux/hwmon.h>
+
+#define DRIVER_NAME "nct1008"
+
+/* Register Addresses */
+#define LOCAL_TEMP_RD			0x00
+#define EXT_HI_TEMP_RD			0x01
+#define EXT_LO_TEMP_RD			0x10
+#define STATUS_RD			0x02
+#define CONFIG_RD			0x03
+
+#define CONFIG_WR			0x09
+#define CONV_RATE_WR			0x0A
+#define LOCAL_TEMP_HI_LIMIT_WR		0x0B
+#define EXT_TEMP_HI_LIMIT_HI_BYTE	0x0D
+#define OFFSET_WR			0x11
+#define EXT_THERM_LIMIT_WR		0x19
+#define LOCAL_THERM_LIMIT_WR		0x20
+#define THERM_HYSTERESIS_WR		0x21
+
+/* Configuration Register Bits */
+#define EXTENDED_RANGE_BIT		(0x1 << 2)
+#define THERM2_BIT			(0x1 << 5)
+#define STANDBY_BIT			(0x1 << 6)
+
+/* Max Temperature Measurements */
+#define EXTENDED_RANGE_OFFSET		64U
+#define STANDARD_RANGE_MAX		127U
+#define EXTENDED_RANGE_MAX		(150U + EXTENDED_RANGE_OFFSET)
+
+static inline u8 temperature_to_value(bool extended, u8 temp);
+
+struct nct1008_data {
+	struct device *hwmon_dev;
+	struct work_struct work;
+	struct i2c_client *client;
+	struct mutex mutex;
+	u8 config;
+	void (*alarm_fn)(bool raised);
+};
+
+static ssize_t nct1008_show_temp(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	signed int temp_value = 0;
+	u8 data = 0;
+
+	if (!dev || !buf || !attr)
+		return -EINVAL;
+
+	data = i2c_smbus_read_byte_data(client, LOCAL_TEMP_RD);
+	if (data < 0) {
+		dev_err(&client->dev, "%s: failed to read "
+			"temperature\n", __func__);
+		return -EINVAL;
+	}
+
+	temp_value = (signed int)data;
+	return sprintf(buf, "%d\n", temp_value);
+}
+
+static ssize_t nct1008_show_ext_temp(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	signed int temp_value = 0;
+	u8 data = 0;
+
+	if (!dev || !buf || !attr)
+		return -EINVAL;
+
+	data = i2c_smbus_read_byte_data(client, EXT_HI_TEMP_RD);
+	if (data < 0) {
+		dev_err(&client->dev, "%s: failed to read "
+			"ext_temperature\n", __func__);
+		return -EINVAL;
+	}
+
+	temp_value = (signed int)data;
+
+	data = i2c_smbus_read_byte_data(client, EXT_LO_TEMP_RD);
+
+	return sprintf(buf, "%d.%d\n", temp_value, (25 * (data >> 6)));
+}
+
+static ssize_t nct1008_store_throttle_ext_limit(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct nct1008_platform_data *pdata = client->dev.platform_data;
+	unsigned long res;
+	u8 ext_limit;
+	u8 value;
+	int err;
+
+	err = strict_strtoul(buf, 0, &res);
+	if (err)
+		return -EINVAL;
+
+	ext_limit = (u8)res;
+
+	/* External Temperature Throttling limit */
+	value = temperature_to_value(pdata->ext_range, ext_limit);
+	err = i2c_smbus_write_byte_data(client,
+					EXT_TEMP_HI_LIMIT_HI_BYTE, value);
+	if (err < 0)
+		return -EINVAL;
+
+	pdata->throttling_ext_limit = ext_limit;
+	return count;
+}
+
+static ssize_t nct1008_show_throttle_ext_limit(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct nct1008_platform_data *pdata = client->dev.platform_data;
+	u8 ext_limit = 0;
+
+	if (!dev || !buf || !attr)
+		return -EINVAL;
+
+	ext_limit = pdata->throttling_ext_limit;
+
+	return sprintf(buf, "%d\n", ext_limit);
+}
+
+static DEVICE_ATTR(temperature, S_IRUGO, nct1008_show_temp, NULL);
+static DEVICE_ATTR(ext_temperature, S_IRUGO, nct1008_show_ext_temp, NULL);
+static DEVICE_ATTR(throttle_ext_limit, S_IRUGO | S_IWUSR,
+		   nct1008_show_throttle_ext_limit,
+		   nct1008_store_throttle_ext_limit);
+
+static struct attribute *nct1008_attributes[] = {
+	&dev_attr_temperature.attr,
+	&dev_attr_ext_temperature.attr,
+	&dev_attr_throttle_ext_limit.attr,
+	NULL
+};
+
+static const struct attribute_group nct1008_attr_group = {
+	.attrs = nct1008_attributes,
+};
+
+static void nct1008_enable(struct i2c_client *client)
+{
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	i2c_smbus_write_byte_data(client, CONFIG_WR,
+				  data->config & ~STANDBY_BIT);
+}
+
+static void nct1008_disable(struct i2c_client *client)
+{
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	i2c_smbus_write_byte_data(client, CONFIG_WR,
+				  data->config | STANDBY_BIT);
+}
+
+
+static void nct1008_work_func(struct work_struct *work)
+{
+	struct nct1008_data *data =
+		container_of(work, struct nct1008_data, work);
+	int irq = data->client->irq;
+
+	mutex_lock(&data->mutex);
+
+	if (data->alarm_fn) {
+		/* Therm2 line is active low */
+		data->alarm_fn(!gpio_get_value(irq_to_gpio(irq)));
+	}
+
+	mutex_unlock(&data->mutex);
+}
+
+static irqreturn_t nct1008_irq(int irq, void *dev_id)
+{
+	struct nct1008_data *data = dev_id;
+	schedule_work(&data->work);
+
+	return IRQ_HANDLED;
+}
+
+static inline u8 value_to_temperature(bool extended, u8 value)
+{
+	return extended ? (u8)(value - EXTENDED_RANGE_OFFSET) : value;
+}
+
+static inline u8 temperature_to_value(bool extended, u8 temp)
+{
+	return extended ? (u8)(temp + EXTENDED_RANGE_OFFSET) : temp;
+}
+
+static int __devinit nct1008_configure_sensor(struct nct1008_data* data)
+{
+	struct i2c_client *client           = data->client;
+	struct nct1008_platform_data *pdata = client->dev.platform_data;
+	u8 value;
+	int err;
+
+	if (!pdata || !pdata->supported_hwrev)
+		return -ENODEV;
+
+	/*
+	 * Initial Configuration - device is placed in standby and
+	 * ALERT/THERM2 pin is configured as THERM2
+	 */
+	data->config = value = pdata->ext_range ?
+		(STANDBY_BIT | THERM2_BIT | EXTENDED_RANGE_BIT) :
+		(STANDBY_BIT | THERM2_BIT);
+
+	err = i2c_smbus_write_byte_data(client, CONFIG_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* Temperature conversion rate */
+	err = i2c_smbus_write_byte_data(client, CONV_RATE_WR, pdata->conv_rate);
+	if (err < 0)
+		goto error;
+
+	/* External temperature h/w shutdown limit */
+	value = temperature_to_value(pdata->ext_range,
+				     pdata->shutdown_ext_limit);
+	err = i2c_smbus_write_byte_data(client, EXT_THERM_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* Local temperature h/w shutdown limit */
+	value = temperature_to_value(pdata->ext_range,
+				     pdata->shutdown_local_limit);
+	err = i2c_smbus_write_byte_data(client, LOCAL_THERM_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* External Temperature Throttling limit */
+	value = temperature_to_value(pdata->ext_range,
+				     pdata->throttling_ext_limit);
+	err = i2c_smbus_write_byte_data(client, EXT_TEMP_HI_LIMIT_HI_BYTE,
+					value);
+	if (err < 0)
+		goto error;
+
+	/* Local Temperature Throttling limit */
+	value = pdata->ext_range ? EXTENDED_RANGE_MAX : STANDARD_RANGE_MAX;
+	err = i2c_smbus_write_byte_data(client, LOCAL_TEMP_HI_LIMIT_WR, value);
+	if (err < 0)
+		goto error;
+
+	/* Remote channel offset */
+	err = i2c_smbus_write_byte_data(client, OFFSET_WR, pdata->offset);
+	if (err < 0)
+		goto error;
+
+	/* THERM hysteresis */
+	err = i2c_smbus_write_byte_data(client, THERM_HYSTERESIS_WR,
+					pdata->hysteresis);
+	if (err < 0)
+		goto error;
+
+	data->alarm_fn = pdata->alarm_fn;
+	return 0;
+error:
+	return err;
+}
+
+static int __devinit nct1008_configure_irq(struct nct1008_data *data)
+{
+	INIT_WORK(&data->work, nct1008_work_func);
+
+	return request_irq(data->client->irq, nct1008_irq, IRQF_TRIGGER_RISING |
+				IRQF_TRIGGER_FALLING, DRIVER_NAME, data);
+}
+
+static int __devinit nct1008_probe(struct i2c_client *client,
+				   const struct i2c_device_id *id)
+{
+	struct nct1008_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct nct1008_data), GFP_KERNEL);
+
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->mutex);
+
+	err = nct1008_configure_sensor(data);	/* sensor is in standby */
+	if (err < 0)
+		goto error;
+
+	err = nct1008_configure_irq(data);
+	if (err < 0)
+		goto error;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		dev_err(&client->dev, "%s: hwmon_device_register "
+			"failed\n", __func__);
+		goto error;
+	}
+
+	/* register sysfs hooks */
+	err = sysfs_create_group(&client->dev.kobj, &nct1008_attr_group);
+	if (err < 0)
+		goto fail_sys;
+
+	nct1008_enable(client);		/* sensor is running */
+
+	schedule_work(&data->work);		/* check initial state */
+
+	return 0;
+
+fail_sys:
+	hwmon_device_unregister(data->hwmon_dev);
+error:
+	kfree(data);
+	return err;
+}
+
+static int __devexit nct1008_remove(struct i2c_client *client)
+{
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	free_irq(data->client->irq, data);
+	cancel_work_sync(&data->work);
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &nct1008_attr_group);
+	kfree(data);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int nct1008_suspend(struct i2c_client *client, pm_message_t state)
+{
+	disable_irq(client->irq);
+	nct1008_disable(client);
+
+	return 0;
+}
+
+static int nct1008_resume(struct i2c_client *client)
+{
+	struct nct1008_data *data = i2c_get_clientdata(client);
+
+	nct1008_enable(client);
+	enable_irq(client->irq);
+	schedule_work(&data->work);
+
+	return 0;
+}
+#endif
+
+static const struct i2c_device_id nct1008_id[] = {
+	{ DRIVER_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, nct1008_id);
+
+static struct i2c_driver nct1008_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+	},
+	.probe		= nct1008_probe,
+	.remove		= __devexit_p(nct1008_remove),
+	.id_table	= nct1008_id,
+#ifdef CONFIG_PM
+	.suspend	= nct1008_suspend,
+	.resume		= nct1008_resume,
+#endif
+};
+
+static int __init nct1008_init(void)
+{
+	return i2c_add_driver(&nct1008_driver);
+}
+
+static void __exit nct1008_exit(void)
+{
+	i2c_del_driver(&nct1008_driver);
+}
+
+MODULE_DESCRIPTION("Temperature sensor driver for OnSemi NCT1008");
+MODULE_LICENSE("GPL");
+
+module_init(nct1008_init);
+module_exit(nct1008_exit);
-- 
1.7.0.4

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