hwmon: (ds1621) Remove detect function
Due to a lack of device and vendor identification registers, the
Dallas/Maxim DS16xx devices cannot be uniquely detected, sometimes
resulting in false positives. Therefore, the detect function is
being removed in favor of explicit device instantiation.
Signed-off-by: Robert Coulson <rob.coulson@gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621
index 1ebaa24..8378066 100644
--- a/Documentation/hwmon/ds1621
+++ b/Documentation/hwmon/ds1621
@@ -4,24 +4,22 @@
Supported chips:
* Dallas Semiconductor / Maxim Integrated DS1621
Prefix: 'ds1621'
- Addresses scanned: I2C 0x48 - 0x4f
+ Addresses scanned: none
Datasheet: Publicly available from www.maximintegrated.com
* Dallas Semiconductor DS1625
- Prefix:
- 'ds1621' - if binding via _detect function
- 'ds1625' - explicit instantiation
- Addresses scanned: I2C 0x48 - 0x4f
+ Prefix: 'ds1625'
+ Addresses scanned: none
Datasheet: Publicly available from www.datasheetarchive.com
* Maxim Integrated DS1631
Prefix: 'ds1631'
- Addresses scanned: I2C 0x48 - 0x4f
+ Addresses scanned: none
Datasheet: Publicly available from www.maximintegrated.com
* Maxim Integrated DS1721
Prefix: 'ds1721'
- Addresses scanned: I2C 0x48 - 0x4f
+ Addresses scanned: none
Datasheet: Publicly available from www.maximintegrated.com
Authors:
@@ -77,12 +75,13 @@
but the DS1621 is meant to replace it. The DS1631 and DS1721 are also
pin compatible with the DS1621, but provide multi-resolution support.
-Since there is no version register, there is no unique identification
-for these devices. In addition, the DS1631 and DS1721 will emulate a
-DS1621 device, if not explicitly instantiated (why? because the detect
-function compares the temperature register values bits and checks for a
-9-bit resolution). Therefore, for correct device identification and
-functionality, explicit device instantiation is required.
+Since there is no version or vendor identification register, there is
+no unique identification for these devices. Therefore, explicit device
+instantiation is required for correct device identification and functionality.
+
+And, for correct identification and operation, each device must be
+explicitly instantiated, one device per address, in this address
+range: 0x48..0x4f.
The DS1721 is pin compatible with the DS1621, has an accuracy of +/- 1.0
degree Celsius over a -10 to +85 degree range, a minimum/maximum alarm
diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c
index 98adf77..8e940ad 100644
--- a/drivers/hwmon/ds1621.c
+++ b/drivers/hwmon/ds1621.c
@@ -46,10 +46,6 @@
#include <linux/sysfs.h>
#include <linux/kernel.h>
-/* Addresses to scan */
-static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
- 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
-
/* Supported devices */
enum chips { ds1621, ds1625, ds1631, ds1721 };
@@ -358,48 +354,6 @@
.is_visible = ds1621_attribute_visible
};
-
-/* Return 0 if detection is successful, -ENODEV otherwise */
-static int ds1621_detect(struct i2c_client *client,
- struct i2c_board_info *info)
-{
- struct i2c_adapter *adapter = client->adapter;
- int conf, temp;
- int i;
-
- if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
- | I2C_FUNC_SMBUS_WORD_DATA
- | I2C_FUNC_SMBUS_WRITE_BYTE))
- return -ENODEV;
-
- /*
- * Now, we do the remaining detection. It is lousy.
- *
- * The NVB bit should be low if no EEPROM write has been requested
- * during the latest 10ms, which is highly improbable in our case.
- */
- conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
- if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
- return -ENODEV;
- /*
- * The ds1621 & ds1625 use 9-bit resolution, so the 7 lowest bits
- * of the temperature should always be 0 (NOTE: The other chips
- * have multi-resolution support, so if they have 9-bit resolution
- * configured and the min/max temperature values set accordingly,
- * then if not explicitly instantiated, they *will* appear as and
- * emulate a ds1621 device).
- */
- for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
- temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
- if (temp < 0 || (temp & 0x7f00))
- return -ENODEV;
- }
-
- strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
-
- return 0;
-}
-
static int ds1621_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -465,8 +419,6 @@
.probe = ds1621_probe,
.remove = ds1621_remove,
.id_table = ds1621_id,
- .detect = ds1621_detect,
- .address_list = normal_i2c,
};
module_i2c_driver(ds1621_driver);