[PATCH] I2C: New lm92 chip driver

Greg KH
2005-03-31T23:59:01Z

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);