hwmon: (tmp102) Various fixes

Fixes from my driver review:
http://lists.lm-sensors.org/pipermail/lm-sensors/2010-March/028051.html

Only the small changes are in there, more important changes will come
later separately as time permits.

* Drop the remnants of the now gone detect function
* The TMP102 has no known compatible chip
* Include the right header files
* Clarify why byte swapping of register values is needed
* Strip resolution info bit from temperature register value
* Set cache lifetime to 1/3 second
* Don't arbitrarily reject limit values; clamp as needed
* Make limit writing unconditional
* Don't check for transaction types the driver doesn't use
* Properly check for error when setting configuration
* Report error on failed probe
* Make the driver load automatically where needed
* Various other minor fixes

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Steven King <sfking@fdwdc.com>

3 files changed, 39 insertions, 42 deletions

diff --git a/Documentation/hwmon/tmp102 b/Documentation/hwmon/tmp102
index 239dded8539f..8454a7763122 100644
--- a/Documentation/hwmon/tmp102
+++ b/Documentation/hwmon/tmp102
@@ -4,7 +4,7 @@ Kernel driver tmp102
 Supported chips:
   * Texas Instruments TMP102
     Prefix: 'tmp102'
-    Addresses scanned: I2C 0x48 0x49 0x4a 0x4b
+    Addresses scanned: none
     Datasheet: http://focus.ti.com/docs/prod/folders/print/tmp102.html
 
 Author:
@@ -15,13 +15,12 @@ Description
 
 The Texas Instruments TMP102 implements one temperature sensor.  Limits can be
 set through the Overtemperature Shutdown register and Hysteresis register.  The
-sensor is accurate to 0.5 degrees over the range of -25 to +85 C, and to 1.0
-degrees from -40 to +125 C. Resolution of the sensor is 0.0625 degree.  The
+sensor is accurate to 0.5 degree over the range of -25 to +85 C, and to 1.0
+degree from -40 to +125 C. Resolution of the sensor is 0.0625 degree.  The
 operating temperature has a minimum of -55 C and a maximum of +150 C.
 
 The TMP102 has a programmable update rate that can select between 8, 4, 1, and
 0.5 Hz. (Currently the driver only supports the default of 4 Hz).
 
 The driver provides the common sysfs-interface for temperatures (see
-/Documentation/hwmon/sysfs-interface under Temperatures).
-
+Documentation/hwmon/sysfs-interface under Temperatures).
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 6d87892a6639..de22ae41f758 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -843,7 +843,7 @@ config SENSORS_THMC50
           will be called thmc50.
 
 config SENSORS_TMP102
-        tristate "Texas Instruments TMP102 and compatibles"
+        tristate "Texas Instruments TMP102"
         depends on I2C && EXPERIMENTAL
         help
           If you say yes here you get support for Texas Instruments TMP102
diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
index e4def62c0ebf..e9de28df0e4d 100644
--- a/drivers/hwmon/tmp102.c
+++ b/drivers/hwmon/tmp102.c
@@ -1,6 +1,6 @@
-/* Texas Instruments TMP102 SMBUS temperature sensor driver
+/* Texas Instruments TMP102 SMBus temperature sensor driver
  *
- * Copyright 2010 Steven King <sfking@fdwdc.com>
+ * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
  *
  * 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
@@ -17,8 +17,6 @@
  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-
-
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -27,7 +25,7 @@
 #include <linux/hwmon-sysfs.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
-#include <linux/delay.h>
+#include <linux/device.h>
 
 #define DRIVER_NAME "tmp102"
 
@@ -56,26 +54,27 @@ struct tmp102 {
         int temp[3];
 };
 
-/* the TMP102 registers are big endian so we have to swab16 the values */
-static int tmp102_read_reg(struct i2c_client *client, u8 reg)
+/* SMBus specifies low byte first, but the TMP102 returns high byte first,
+ * so we have to swab16 the values */
+static inline int tmp102_read_reg(struct i2c_client *client, u8 reg)
 {
         int result = i2c_smbus_read_word_data(client, reg);
         return result < 0 ? result : swab16(result);
 }
 
-static int tmp102_write_reg(struct i2c_client *client, u8 reg, u16 val)
+static inline int tmp102_write_reg(struct i2c_client *client, u8 reg, u16 val)
 {
         return i2c_smbus_write_word_data(client, reg, swab16(val));
 }
 
-/* convert left adjusted 13bit TMP102 register value to miliCelsius */
-static int tmp102_reg_to_mC(s16 val)
+/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
+static inline int tmp102_reg_to_mC(s16 val)
 {
-        return (val * 1000) / 128;
+        return ((val & ~0x01) * 1000) / 128;
 }
 
-/* convert miliCelsius to left adjusted 13bit TMP102 register value */
-static u16 tmp102_mC_to_reg(int val)
+/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
+static inline u16 tmp102_mC_to_reg(int val)
 {
         return (val * 128) / 1000;
 }
@@ -91,7 +90,7 @@ static struct tmp102 *tmp102_update_device(struct i2c_client *client)
         struct tmp102 *tmp102 = i2c_get_clientdata(client);
 
         mutex_lock(&tmp102->lock);
-        if (time_after(jiffies, tmp102->last_update + HZ / 4)) {
+        if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
                 int i;
                 for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
                         int status = tmp102_read_reg(client, tmp102_reg[i]);
@@ -122,16 +121,16 @@ static ssize_t tmp102_set_temp(struct device *dev,
         struct i2c_client *client = to_i2c_client(dev);
         struct tmp102 *tmp102 = i2c_get_clientdata(client);
         long val;
-        int status = 0;
+        int status;
 
-        if ((strict_strtol(buf, 10, &val) < 0) || (abs(val) > 150000))
+        if (strict_strtol(buf, 10, &val) < 0)
                 return -EINVAL;
+        val = SENSORS_LIMIT(val, -256000, 255000);
+
         mutex_lock(&tmp102->lock);
-        if (tmp102->temp[sda->index] != val) {
-                tmp102->temp[sda->index] = val;
-                status = tmp102_write_reg(client, tmp102_reg[sda->index],
-                                          tmp102_mC_to_reg(val));
-        }
+        tmp102->temp[sda->index] = val;
+        status = tmp102_write_reg(client, tmp102_reg[sda->index],
+                                  tmp102_mC_to_reg(val));
         mutex_unlock(&tmp102->lock);
         return status ? : count;
 }
@@ -164,9 +163,10 @@ static int __devinit tmp102_probe(struct i2c_client *client,
         struct tmp102 *tmp102;
         int status;
 
-        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+        if (!i2c_check_functionality(client->adapter,
                                      I2C_FUNC_SMBUS_WORD_DATA)) {
-                dev_dbg(&client->dev, "adapter doesnt support SMBUS\n");
+                dev_err(&client->dev, "adapter doesnt support SMBus word "
+                        "transactions\n");
                 return -ENODEV;
         }
 
@@ -177,16 +177,20 @@ static int __devinit tmp102_probe(struct i2c_client *client,
         }
         i2c_set_clientdata(client, tmp102);
 
-        tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONFIG);
+        status = tmp102_write_reg(client, TMP102_CONF_REG, TMP102_CONFIG);
+        if (status < 0) {
+                dev_err(&client->dev, "error writing config register\n");
+                goto fail0;
+        }
         status = tmp102_read_reg(client, TMP102_CONF_REG);
         if (status < 0) {
-                dev_dbg(&client->dev, "error reading config register\n");
+                dev_err(&client->dev, "error reading config register\n");
                 goto fail0;
         }
         status &= ~TMP102_CONFIG_RD_ONLY;
         if (status != TMP102_CONFIG) {
-                dev_dbg(&client->dev, "could not verify config settings\n");
-                status = -EIO;
+                dev_err(&client->dev, "config settings did not stick\n");
+                status = -ENODEV;
                 goto fail0;
         }
         tmp102->last_update = jiffies - HZ;
@@ -213,7 +217,7 @@ fail0:
         i2c_set_clientdata(client, NULL);
         kfree(tmp102);
 
-        return 0;
+        return status;
 }
 
 static int __devexit tmp102_remove(struct i2c_client *client)
@@ -260,23 +264,18 @@ static const struct dev_pm_ops tmp102_dev_pm_ops = {
 #define TMP102_DEV_PM_OPS NULL
 #endif /* CONFIG_PM */
 
-static const unsigned short normal_i2c[] = {
-        0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END
-};
-
 static const struct i2c_device_id tmp102_id[] = {
-        { DRIVER_NAME, 0 },
+        { "tmp102", 0 },
         { }
 };
+MODULE_DEVICE_TABLE(i2c, tmp102_id);
 
 static struct i2c_driver tmp102_driver = {
         .driver.name    = DRIVER_NAME,
         .driver.pm      = TMP102_DEV_PM_OPS,
-        .class          = I2C_CLASS_HWMON,
         .probe          = tmp102_probe,
         .remove         = __devexit_p(tmp102_remove),
         .id_table       = tmp102_id,
-        .address_list   = normal_i2c,
 };
 
 static int __init tmp102_init(void)
@@ -291,7 +290,6 @@ static void __exit tmp102_exit(void)
 }
 module_exit(tmp102_exit);
 
-
 MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
 MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
 MODULE_LICENSE("GPL");