TI's TMP421/422/423 are I2C temperature sensor chips. These chips are
similar to TI's TMP401/411 chips, but with reduced functionality (only
temperature measurement). The chips have one local sensor and up to
three (TMP423) remote sensors.
Notes:
Hans, I've dropped two checks in tmp421_detect(). These checks came
from tmp401 (copied by your students).
1. Are reserved bits set to 0 in configuration register?
2. Are unused bits in conversion rate register set to 0?
I haven't any experience with real chips, so my question: Do we need
these checks. Isn't the device id check enough? If so, I will bring
back these checks.
Signed-off-by: Andre Prendel <andre.prendel at gmx.de>
---
Kconfig | 10 +
Makefile | 1
tmp421.c | 331 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 342 insertions(+)
Index: linux-2.6/drivers/hwmon/tmp421.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/drivers/hwmon/tmp421.c 2009-06-12 22:13:34.000000000 +0200
@@ -0,0 +1,331 @@
+/* tmp421.c
+ *
+ * Copyright (C) 2009 Andre Prendel <andre.prendel at gmx.de>
+ * Preliminary support by:
+ * Melvin Rook, Raymond Ng
+ *
+ * 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.
+ */
+
+/*
+ * Driver for the Texas Instruments TMP421 SMBUS temperature sensor IC.
+ * Supported models: TMP421, TMP422, TMP423
+ */
+
+#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>
+
+/* Addresses to scan */
+static unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
+ I2C_CLIENT_END };
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_3(tmp421, tmp422, tmp423);
+
+/* The TMP421 registers */
+#define TMP421_STATUS_REG 0x08
+#define TMP421_CONFIG_REG_1 0x09
+#define TMP421_CONFIG_REG_2 0x0A
+#define TMP421_CONVERSION_RATE_REG 0x0B
+#define TMP421_MANUFACTURER_ID_REG 0xFE
+#define TMP421_DEVICE_ID_REG 0xFF
+
+static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
+static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
+
+/* Flags */
+#define TMP421_CONFIG_SHUTDOWN 0x40
+#define TMP421_CONFIG_RANGE 0x04
+
+/* Manufacturer / Device ID's */
+#define TMP421_MANUFACTURER_ID 0x55
+#define TMP421_DEVICE_ID 0x21
+#define TMP422_DEVICE_ID 0x22
+#define TMP423_DEVICE_ID 0x23
+
+static int tmp421_probe(struct i2c_client *client,
+ const struct i2c_device_id *id);
+static int tmp421_detect(struct i2c_client *client, int kind,
+ struct i2c_board_info *info);
+static int tmp421_remove(struct i2c_client *client);
+static struct tmp421_data *tmp421_update_device(struct device *dev);
+
+static const struct i2c_device_id tmp421_id[] = {
+ { "tmp421", tmp421 },
+ { "tmp422", tmp422 },
+ { "tmp423", tmp423 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, tmp421_id);
+
+static struct i2c_driver tmp421_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "tmp421",
+ },
+ .probe = tmp421_probe,
+ .remove = tmp421_remove,
+ .id_table = tmp421_id,
+ .detect = tmp421_detect,
+ .address_data = &addr_data,
+};
+
+struct tmp421_data {
+ struct device *hwmon_dev;
+ struct mutex update_lock;
+ char valid;
+ unsigned long last_updated;
+ int kind;
+ u8 config;
+ s16 temp[4];
+};
+
+static int temp_from_s16(s16 reg)
+{
+ int temp = reg;
+
+ return (temp * 1000 + 128) / 256;
+}
+
+static int temp_from_u16(u16 reg)
+{
+ int temp = reg;
+
+ /* Add offset for extended temperature range. */
+ temp -= 64 * 256;
+
+ return (temp * 1000 + 128) / 256;
+}
+
+static ssize_t show_temp_value(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ int index = to_sensor_dev_attr(devattr)->index;
+ struct tmp421_data *data = tmp421_update_device(dev);
+ int temp;
+
+ if (data->config & TMP421_CONFIG_RANGE)
+ temp = temp_from_u16(data->temp[index]);
+ else
+ temp = temp_from_s16(data->temp[index]);
+
+ return sprintf(buf, "%d\n", temp);
+}
+
+static ssize_t show_fault(struct device *dev,
+ struct device_attribute *devattr, char *buf)
+{
+ int index = to_sensor_dev_attr(devattr)->index;
+ struct tmp421_data *data = tmp421_update_device(dev);
+
+ /*
+ * The OPEN bit signals a fault. This is bit 0 of the temperature
+ * register (low byte).
+ */
+ if (data->temp[index] & 0x01)
+ return sprintf(buf, "1\n");
+ else
+ return sprintf(buf, "0\n");
+}
+
+static struct sensor_device_attribute tmp421_attr[] = {
+ SENSOR_ATTR(temp1_input, 0444, show_temp_value, NULL, 0),
+ SENSOR_ATTR(temp2_input, 0444, show_temp_value, NULL, 1),
+ SENSOR_ATTR(temp2_fault, 0444, show_fault, NULL, 1),
+ SENSOR_ATTR(temp3_input, 0444, show_temp_value, NULL, 2),
+ SENSOR_ATTR(temp3_fault, 0444, show_fault, NULL, 2),
+ SENSOR_ATTR(temp4_input, 0444, show_temp_value, NULL, 3),
+ SENSOR_ATTR(temp4_fault, 0444, show_fault, NULL, 3),
+};
+
+static void tmp421_init_client(struct i2c_client *client)
+{
+ int config, config_orig;
+
+ /* Set the conversion rate to 2 Hz */
+ i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
+
+ /* Start conversions (disable shutdown if necessary) */
+ config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
+ if (config < 0) {
+ dev_warn(&client->dev, "Could not read configuration"
+ "register (%d)\n", config);
+ return;
+ }
+
+ config_orig = config;
+ config &= ~TMP421_CONFIG_SHUTDOWN;
+
+ if (config != config_orig)
+ i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
+}
+
+static int tmp421_detect(struct i2c_client *client, int kind,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -ENODEV;
+
+ if (kind <= 0) {
+ u8 reg;
+
+ reg = i2c_smbus_read_byte_data(client,
+ TMP421_MANUFACTURER_ID_REG);
+
+ if (reg != TMP421_MANUFACTURER_ID)
+ return -ENODEV;
+
+ reg = i2c_smbus_read_byte_data(client,
+ TMP421_DEVICE_ID_REG);
+
+ switch (reg) {
+ case TMP421_DEVICE_ID:
+ kind = tmp421;
+ break;
+ case TMP422_DEVICE_ID:
+ kind = tmp422;
+ break;
+ case TMP423_DEVICE_ID:
+ kind = tmp423;
+ break;
+ default:
+ return -ENODEV;
+
+ }
+ }
+ strlcpy(info->type, tmp421_id[kind - 1].name, I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static int tmp421_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct tmp421_data *data;
+ const char *names[] = { "TMP421", "TMP422", "TMP423" };
+ int i, err;
+
+ data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
+ if (!data)
+ return -ENODEV;
+
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->update_lock);
+ data->kind = id->driver_data;
+
+ tmp421_init_client(client);
+
+ for (i = 0; i < ARRAY_SIZE(tmp421_attr); i++) {
+ err = device_create_file(&client->dev,
+ &tmp421_attr[i].dev_attr);
+
+ if (err)
+ goto exit_remove;
+
+ /*
+ * Create only necessary sysfs files.
+ * TMP421 up to one remote sensor
+ * TMP422 up to two remote sensors
+ * TMP423 up to three remote sensors.
+ */
+ if (i >= data->kind * 2)
+ break;
+ }
+
+ data->hwmon_dev = hwmon_device_register(&client->dev);
+ if (IS_ERR(data->hwmon_dev)) {
+ err = PTR_ERR(data->hwmon_dev);
+ data->hwmon_dev = NULL;
+ goto exit_remove;
+ }
+
+ dev_info(&client->dev, "Detected TI %s chip\n", names[data->kind - 1]);
+ return 0;
+
+exit_remove:
+ tmp421_remove(client);
+ return err;
+}
+
+static int tmp421_remove(struct i2c_client *client)
+{
+ struct tmp421_data *data = i2c_get_clientdata(client);
+ int i;
+
+ if (data->hwmon_dev)
+ hwmon_device_unregister(data->hwmon_dev);
+
+ for (i = 0; i < ARRAY_SIZE(tmp421_attr); i++)
+ device_remove_file(&client->dev, &tmp421_attr[i].dev_attr);
+
+ kfree(data);
+
+ return 0;
+}
+
+static struct tmp421_data *tmp421_update_device(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct tmp421_data *data = i2c_get_clientdata(client);
+ int i;
+
+ mutex_lock(&data->update_lock);
+
+ if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
+ data->config = i2c_smbus_read_byte_data(client,
+ TMP421_CONFIG_REG_1);
+
+ for (i = 0; i <= data->kind; i++) {
+ data->temp[i] = i2c_smbus_read_byte_data(client,
+ TMP421_TEMP_MSB[i]) << 8;
+ data->temp[i] |= i2c_smbus_read_byte_data(client,
+ TMP421_TEMP_LSB[i]);
+ }
+ data->last_updated = jiffies;
+ data->valid = 1;
+ }
+
+ mutex_unlock(&data->update_lock);
+
+ return data;
+}
+
+static int __init tmp421_init(void)
+{
+ return i2c_add_driver(&tmp421_driver);
+}
+
+static void __exit tmp421_exit(void)
+{
+ i2c_del_driver(&tmp421_driver);
+}
+
+MODULE_AUTHOR("Andre Prendel");
+MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
+ "driver");
+MODULE_LICENSE("GPL");
+
+module_init(tmp421_init);
+module_exit(tmp421_exit);
Index: linux-2.6/drivers/hwmon/Kconfig
===================================================================
--- linux-2.6.orig/drivers/hwmon/Kconfig 2009-06-11 21:50:46.000000000 +0200
+++ linux-2.6/drivers/hwmon/Kconfig 2009-06-11 21:50:46.000000000 +0200
@@ -797,6 +797,16 @@
This driver can also be built as a module. If so, the module
will be called tmp401.
+config SENSORS_TMP421
+ tristate "Texas Instruments TMP421 and compatibles"
+ depends on I2C && EXPERIMENTAL
+ help
+ If you say yes here you get support for Texas Instruments TMP421
+ temperature sensor chips.
+
+ This driver can also be built as a module. If so, the module
+ will be called tmp421.
+
config SENSORS_VIA686A
tristate "VIA686A"
depends on PCI
Index: linux-2.6/drivers/hwmon/Makefile
===================================================================
--- linux-2.6.orig/drivers/hwmon/Makefile 2009-06-11 21:50:46.000000000 +0200
+++ linux-2.6/drivers/hwmon/Makefile 2009-06-11 21:50:46.000000000 +0200
@@ -83,6 +83,7 @@
obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
obj-$(CONFIG_SENSORS_THMC50) += thmc50.o
obj-$(CONFIG_SENSORS_TMP401) += tmp401.o
+obj-$(CONFIG_SENSORS_TMP421) += tmp421.o
obj-$(CONFIG_SENSORS_VIA686A) += via686a.o
obj-$(CONFIG_SENSORS_VT1211) += vt1211.o
obj-$(CONFIG_SENSORS_VT8231) += vt8231.o
