[PATCH] I2C: New lm92 chip driver

[Greg KH <gregkh@suse.de>]

ChangeSet 1.2324, 2005/03/31 14:05:50-08:00, khali@linux-fr.org

[PATCH] I2C: New lm92 chip driver

This is a new i2c chip driver named lm92. It supports the National
Semiconductor LM92 and Maxim MAX6635 chips. This time I did not port the
driver from the lm_sensors project but instead rewrote it. The reason is
that the original driver has a different structure from the other i2c
chip drivers, which would have made maintenance harder.

I don't have a compatible chip myself but could test my code thanks to
Mark Hoffman's i2c-stub fake bus driver. Later on, James Chapman tested
it on a real chip, successfully.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


 drivers/i2c/chips/Kconfig  |   11 +
 drivers/i2c/chips/Makefile |    1 
 drivers/i2c/chips/lm92.c   |  423 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 435 insertions(+)


diff -Nru a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
--- a/drivers/i2c/chips/Kconfig	2005-03-31 15:19:07 -08:00
+++ b/drivers/i2c/chips/Kconfig	2005-03-31 15:19:07 -08:00
@@ -236,6 +236,17 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called lm90.
 
+config SENSORS_LM92
+	tristate "National Semiconductor LM92 and compatibles"
+	depends on I2C && EXPERIMENTAL
+	select I2C_SENSOR
+	help
+	  If you say yes here you get support for National Semiconductor LM92
+	  and Maxim MAX6635 sensor chips.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called lm92.
+
 config SENSORS_MAX1619
 	tristate "Maxim MAX1619 sensor chip"
 	depends on I2C && EXPERIMENTAL
diff -Nru a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
--- a/drivers/i2c/chips/Makefile	2005-03-31 15:19:07 -08:00
+++ b/drivers/i2c/chips/Makefile	2005-03-31 15:19:07 -08:00
@@ -27,6 +27,7 @@
 obj-$(CONFIG_SENSORS_LM85)	+= lm85.o
 obj-$(CONFIG_SENSORS_LM87)	+= lm87.o
 obj-$(CONFIG_SENSORS_LM90)	+= lm90.o
+obj-$(CONFIG_SENSORS_LM92)	+= lm92.o
 obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o
 obj-$(CONFIG_SENSORS_M41T00)	+= m41t00.o
 obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o
diff -Nru a/drivers/i2c/chips/lm92.c b/drivers/i2c/chips/lm92.c
--- /dev/null	Wed Dec 31 16:00:00 196900
+++ b/drivers/i2c/chips/lm92.c	2005-03-31 15:19:07 -08:00
@@ -0,0 +1,423 @@
+/*
+ * lm92 - Hardware monitoring driver
+ * Copyright (C) 2005  Jean Delvare <khali@linux-fr.org>
+ *
+ * Based on the lm90 driver, with some ideas taken from the lm_sensors
+ * lm92 driver as well.
+ *
+ * The LM92 is a sensor chip made by National Semiconductor. It reports
+ * its own temperature with a 0.0625 deg resolution and a 0.33 deg
+ * accuracy. Complete datasheet can be obtained from National's website
+ * at:
+ *   http://www.national.com/pf/LM/LM92.html
+ *
+ * This driver also supports the MAX6635 sensor chip made by Maxim.
+ * This chip is compatible with the LM92, but has a lesser accuracy
+ * (1.0 deg). Complete datasheet can be obtained from Maxim's website
+ * at:
+ *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
+ *
+ * Since the LM92 was the first chipset supported by this driver, most
+ * comments will refer to this chipset, but are actually general and
+ * concern all supported chipsets, unless mentioned otherwise.
+ *
+ * Support could easily be added for the National Semiconductor LM76
+ * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
+ * with the LM92.
+ *
+ * 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/i2c.h>
+#include <linux/i2c-sensor.h>
+
+
+/* The LM92 and MAX6635 have 2 two-state pins for address selection,
+   resulting in 4 possible addresses. */
+static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
+				       I2C_CLIENT_END };
+static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END };
+
+/* Insmod parameters */
+SENSORS_INSMOD_1(lm92);
+
+/* The LM92 registers */
+#define LM92_REG_CONFIG			0x01 /* 8-bit, RW */
+#define LM92_REG_TEMP			0x00 /* 16-bit, RO */
+#define LM92_REG_TEMP_HYST		0x02 /* 16-bit, RW */
+#define LM92_REG_TEMP_CRIT		0x03 /* 16-bit, RW */
+#define LM92_REG_TEMP_LOW		0x04 /* 16-bit, RW */
+#define LM92_REG_TEMP_HIGH		0x05 /* 16-bit, RW */
+#define LM92_REG_MAN_ID			0x07 /* 16-bit, RO, LM92 only */
+
+/* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
+   left-justified in 16-bit registers. No rounding is done, with such
+   a resolution it's just not worth it. Note that the MAX6635 doesn't
+   make use of the 4 lower bits for limits (i.e. effective resolution
+   for limits is 1 degree Celsius). */
+static inline int TEMP_FROM_REG(s16 reg)
+{
+	return reg / 8 * 625 / 10;
+}
+
+static inline s16 TEMP_TO_REG(int val)
+{
+	if (val <= -60000)
+		return -60000 * 10 / 625 * 8;
+	if (val >= 160000)
+		return 160000 * 10 / 625 * 8;
+	return val * 10 / 625 * 8;
+}
+
+/* Alarm flags are stored in the 3 LSB of the temperature register */
+static inline u8 ALARMS_FROM_REG(s16 reg)
+{
+	return reg & 0x0007;
+}
+
+/* Driver data (common to all clients) */
+static struct i2c_driver lm92_driver;
+
+/* Client data (each client gets its own) */
+struct lm92_data {
+	struct i2c_client client;
+	struct semaphore update_lock;
+	char valid; /* zero until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* registers values */
+	s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
+};
+
+
+/*
+ * Sysfs attributes and callback functions
+ */
+
+static struct lm92_data *lm92_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm92_data *data = i2c_get_clientdata(client);
+
+	down(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ)
+	 || !data->valid) {
+		dev_dbg(&client->dev, "Updating lm92 data\n");
+		data->temp1_input = swab16(i2c_smbus_read_word_data(client,
+				    LM92_REG_TEMP));
+		data->temp1_hyst = swab16(i2c_smbus_read_word_data(client,
+				    LM92_REG_TEMP_HYST));
+		data->temp1_crit = swab16(i2c_smbus_read_word_data(client,
+				    LM92_REG_TEMP_CRIT));
+		data->temp1_min = swab16(i2c_smbus_read_word_data(client,
+				    LM92_REG_TEMP_LOW));
+		data->temp1_max = swab16(i2c_smbus_read_word_data(client,
+				    LM92_REG_TEMP_HIGH));
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	up(&data->update_lock);
+
+	return data;
+}
+
+#define show_temp(value) \
+static ssize_t show_##value(struct device *dev, char *buf) \
+{ \
+	struct lm92_data *data = lm92_update_device(dev); \
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
+}
+show_temp(temp1_input);
+show_temp(temp1_crit);
+show_temp(temp1_min);
+show_temp(temp1_max);
+
+#define set_temp(value, reg) \
+static ssize_t set_##value(struct device *dev, const char *buf, \
+	size_t count) \
+{ \
+	struct i2c_client *client = to_i2c_client(dev); \
+	struct lm92_data *data = i2c_get_clientdata(client); \
+	long val = simple_strtol(buf, NULL, 10); \
+	data->value = TEMP_TO_REG(val); \
+	i2c_smbus_write_word_data(client, reg, swab16(data->value)); \
+	return count; \
+}
+set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
+set_temp(temp1_min, LM92_REG_TEMP_LOW);
+set_temp(temp1_max, LM92_REG_TEMP_HIGH);
+
+static ssize_t show_temp1_crit_hyst(struct device *dev, char *buf)
+{
+	struct lm92_data *data = lm92_update_device(dev);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
+		       - TEMP_FROM_REG(data->temp1_hyst));
+}
+static ssize_t show_temp1_max_hyst(struct device *dev, char *buf)
+{
+	struct lm92_data *data = lm92_update_device(dev);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
+		       - TEMP_FROM_REG(data->temp1_hyst));
+}
+static ssize_t show_temp1_min_hyst(struct device *dev, char *buf)
+{
+	struct lm92_data *data = lm92_update_device(dev);
+	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
+		       + TEMP_FROM_REG(data->temp1_hyst));
+}
+
+static ssize_t set_temp1_crit_hyst(struct device *dev, const char *buf,
+	size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct lm92_data *data = i2c_get_clientdata(client);
+	data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) -
+			   simple_strtol(buf, NULL, 10);
+	i2c_smbus_write_word_data(client, LM92_REG_TEMP_HYST,
+				  swab16(TEMP_TO_REG(data->temp1_hyst)));
+	return count;
+}
+
+static ssize_t show_alarms(struct device *dev, char *buf)
+{
+	struct lm92_data *data = lm92_update_device(dev);
+	return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
+}
+
+static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
+static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
+	set_temp1_crit);
+static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
+	set_temp1_crit_hyst);
+static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
+	set_temp1_min);
+static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
+static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
+	set_temp1_max);
+static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
+static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
+
+
+/*
+ * Detection and registration
+ */
+
+static void lm92_init_client(struct i2c_client *client)
+{
+	u8 config;
+
+	/* Start the conversions if needed */
+	config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
+	if (config & 0x01)
+		i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
+					  config & 0xFE);
+}
+
+/* The MAX6635 has no identification register, so we have to use tricks
+   to identify it reliably. This is somewhat slow.
+   Note that we do NOT rely on the 2 MSB of the configuration register
+   always reading 0, as suggested by the datasheet, because it was once
+   reported not to be true. */
+static int max6635_check(struct i2c_client *client)
+{
+	u16 temp_low, temp_high, temp_hyst, temp_crit;
+	u8 conf;
+	int i;
+
+	/* No manufacturer ID register, so a read from this address will
+	   always return the last read value. */
+	temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
+	if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
+		return 0;
+	temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
+	if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
+		return 0;
+	
+	/* Limits are stored as integer values (signed, 9-bit). */
+	if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
+		return 0;
+	temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
+	temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
+	if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
+		return 0;
+
+	/* Registers addresses were found to cycle over 16-byte boundaries.
+	   We don't test all registers with all offsets so as to save some
+	   reads and time, but this should still be sufficient to dismiss
+	   non-MAX6635 chips. */
+	conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
+	for (i=16; i<96; i*=2) {
+		if (temp_hyst != i2c_smbus_read_word_data(client,
+		 		 LM92_REG_TEMP_HYST + i - 16)
+		 || temp_crit != i2c_smbus_read_word_data(client,
+		 		 LM92_REG_TEMP_CRIT + i)
+		 || temp_low != i2c_smbus_read_word_data(client,
+				LM92_REG_TEMP_LOW + i + 16)
+		 || temp_high != i2c_smbus_read_word_data(client,
+		 		 LM92_REG_TEMP_HIGH + i + 32)
+		 || conf != i2c_smbus_read_byte_data(client,
+		 	    LM92_REG_CONFIG + i))
+			return 0;
+	}
+
+	return 1;
+}
+
+/* The following function does more than just detection. If detection
+   succeeds, it also registers the new chip. */
+static int lm92_detect(struct i2c_adapter *adapter, int address, int kind)
+{
+	struct i2c_client *new_client;
+	struct lm92_data *data;
+	int err = 0;
+	char *name;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
+					    | I2C_FUNC_SMBUS_WORD_DATA))
+		goto exit;
+
+	if (!(data = kmalloc(sizeof(struct lm92_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+	memset(data, 0, sizeof(struct lm92_data));
+
+	/* Fill in enough client fields so that we can read from the chip,
+	   which is required for identication */
+	new_client = &data->client;
+	i2c_set_clientdata(new_client, data);
+	new_client->addr = address;
+	new_client->adapter = adapter;
+	new_client->driver = &lm92_driver;
+	new_client->flags = 0;
+
+	/* A negative kind means that the driver was loaded with no force
+	   parameter (default), so we must identify the chip. */
+	if (kind < 0) {
+		u8 config = i2c_smbus_read_byte_data(new_client,
+			     LM92_REG_CONFIG);
+		u16 man_id = i2c_smbus_read_word_data(new_client,
+			     LM92_REG_MAN_ID);
+
+		if ((config & 0xe0) == 0x00
+		 && man_id == 0x0180) {
+			pr_info("lm92: Found National Semiconductor LM92 chip\n");
+	 		kind = lm92;
+		} else
+		if (max6635_check(new_client)) {
+			pr_info("lm92: Found Maxim MAX6635 chip\n");
+			kind = lm92; /* No separate prefix */
+		}
+		else
+			goto exit_free;
+	} else
+	if (kind == 0) /* Default to an LM92 if forced */
+		kind = lm92;
+
+	/* Give it the proper name */
+	if (kind == lm92) {
+		name = "lm92";
+	} else { /* Supposedly cannot happen */
+		dev_dbg(&new_client->dev, "Kind out of range?\n");
+		goto exit_free;
+	}
+
+	/* Fill in the remaining client fields */
+	strlcpy(new_client->name, name, I2C_NAME_SIZE);
+	data->valid = 0;
+	init_MUTEX(&data->update_lock);
+
+	/* Tell the i2c subsystem a new client has arrived */
+	if ((err = i2c_attach_client(new_client)))
+		goto exit_free;
+
+	/* Initialize the chipset */
+	lm92_init_client(new_client);
+
+	/* Register sysfs hooks */
+	device_create_file(&new_client->dev, &dev_attr_temp1_input);
+	device_create_file(&new_client->dev, &dev_attr_temp1_crit);
+	device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst);
+	device_create_file(&new_client->dev, &dev_attr_temp1_min);
+	device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst);
+	device_create_file(&new_client->dev, &dev_attr_temp1_max);
+	device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst);
+	device_create_file(&new_client->dev, &dev_attr_alarms);
+
+	return 0;
+
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static int lm92_attach_adapter(struct i2c_adapter *adapter)
+{
+	if (!(adapter->class & I2C_CLASS_HWMON))
+		return 0;
+	return i2c_detect(adapter, &addr_data, lm92_detect);
+}
+
+static int lm92_detach_client(struct i2c_client *client)
+{
+	int err;
+
+	if ((err = i2c_detach_client(client))) {
+		dev_err(&client->dev, "Client deregistration failed, "
+			"client not detached.\n");
+		return err;
+	}
+
+	kfree(i2c_get_clientdata(client));
+	return 0;
+}
+
+
+/*
+ * Module and driver stuff
+ */
+
+static struct i2c_driver lm92_driver = {
+	.owner		= THIS_MODULE,
+	.name		= "lm92",
+	.id		= I2C_DRIVERID_LM92,
+	.flags		= I2C_DF_NOTIFY,
+	.attach_adapter	= lm92_attach_adapter,
+	.detach_client	= lm92_detach_client,
+};
+
+static int __init sensors_lm92_init(void)
+{
+	return i2c_add_driver(&lm92_driver);
+}
+
+static void __exit sensors_lm92_exit(void)
+{
+	i2c_del_driver(&lm92_driver);
+}
+
+MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
+MODULE_DESCRIPTION("LM92/MAX6635 driver");
+MODULE_LICENSE("GPL");
+
+module_init(sensors_lm92_init);
+module_exit(sensors_lm92_exit);

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