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authorAlvaro G. M <alvaro.gamez@hazent.com>2018-03-21 16:04:52 +0100
committerGuenter Roeck <linux@roeck-us.net>2018-03-22 09:32:05 -0700
commit05993e226ad997682929dec2c42477d5e3e6c274 (patch)
treecf271dc92ae6b750b80c48618851d86a29cd94c0 /drivers/hwmon
parent72816cb06e7153c22aed8776949f558b635aa2c0 (diff)
hwmon: (lm92) Do not try to detect MAX6635
Maxim MAX663x family are mostly compatible with LM92, but they lack any identification register. Weakening the detect function would make it prone to false positives, and current one doesn't detect all chips. Therefore, the detect function for max6635 devices is removed in favor of explicit device instatiation. Signed-off-by: Alvaro Gamez Machado <alvaro.gamez@hazent.com> Reviewed-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/lm92.c58
1 files changed, 0 insertions, 58 deletions
diff --git a/drivers/hwmon/lm92.c b/drivers/hwmon/lm92.c
index 2a91974a10bb..18509b5af11e 100644
--- a/drivers/hwmon/lm92.c
+++ b/drivers/hwmon/lm92.c
@@ -259,62 +259,6 @@ static void lm92_init_client(struct i2c_client *client)
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;
-}
-
static struct attribute *lm92_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_crit.dev_attr.attr,
@@ -348,8 +292,6 @@ static int lm92_detect(struct i2c_client *new_client,
if ((config & 0xe0) == 0x00 && man_id == 0x0180)
pr_info("lm92: Found National Semiconductor LM92 chip\n");
- else if (max6635_check(new_client))
- pr_info("lm92: Found Maxim MAX6635 chip\n");
else
return -ENODEV;