On 10/12/11 16:19, Guenter Roeck wrote: > On Wed, 2011-10-12 at 05:36 -0400, michael.hennerich@xxxxxxxxxx wrote: >> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx> >> >> The Analog Devices ADT75 has an additional register at 0x04 >> for initiating oneshot captures. It is not actively used in >> this driver but we must avoid assuming it will behave as >> 0x05-0x07 do and return the last read value. In fact register 0x04 >> reads the same as register 0x00. And all registers are repetitive >> mirrored around register 0x04. This fact is used to detect the ADT75. >> >> This patch is based on an reworked proposal from Jonathan Cameron <jic23@xxxxxxxxx> >> >> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx> >> --- >> Documentation/hwmon/lm75 | 5 +++++ >> drivers/hwmon/Kconfig | 1 + >> drivers/hwmon/lm75.c | 30 ++++++++++++++++++++++++++---- >> 3 files changed, 32 insertions(+), 4 deletions(-) >> >> diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75 >> index a179040..8d40d0f 100644 >> --- a/Documentation/hwmon/lm75 >> +++ b/Documentation/hwmon/lm75 >> @@ -32,6 +32,11 @@ Supported chips: >> Addresses scanned: I2C 0x48 - 0x4f >> Datasheet: Publicly available at the Microchip website >> http://www.microchip.com/ >> + * Analog Devices ADT75 >> + Prefix: 'adt75' >> + Addresses scanned: I2C 0x48 - 0x4f >> + Datasheet: Publicly available at the Analog Devices website >> + http://www.analog.com/adt75 >> >> Author: Frodo Looijaard <frodol@xxxxxx> >> >> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig >> index 0b62c3c..497fd14 100644 >> --- a/drivers/hwmon/Kconfig >> +++ b/drivers/hwmon/Kconfig >> @@ -531,6 +531,7 @@ config SENSORS_LM75 >> If you say yes here you get support for one common type of >> temperature sensor chip, with models including: >> >> + - Analog Devices ADT75 >> - Dallas Semiconductor DS75 and DS1775 >> - Maxim MAX6625 and MAX6626 >> - Microchip MCP980x >> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c >> index ef902d5..0f0291c 100644 >> --- a/drivers/hwmon/lm75.c >> +++ b/drivers/hwmon/lm75.c >> @@ -35,6 +35,7 @@ >> */ >> >> enum lm75_type { /* keep sorted in alphabetical order */ >> + adt75, >> ds1775, >> ds75, >> lm75, >> @@ -213,6 +214,7 @@ static int lm75_remove(struct i2c_client *client) >> } >> >> static const struct i2c_device_id lm75_ids[] = { >> + { "adt75", adt75, }, >> { "ds1775", ds1775, }, >> { "ds75", ds75, }, >> { "lm75", lm75, }, >> @@ -241,7 +243,7 @@ static int lm75_detect(struct i2c_client *new_client, >> struct i2c_adapter *adapter = new_client->adapter; >> int i; >> int conf, hyst, os; >> - bool is_lm75a = 0; >> + bool is_lm75a = 0, is_adt75 = 0; >> >> if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | >> I2C_FUNC_SMBUS_WORD_DATA)) >> @@ -259,7 +261,15 @@ static int lm75_detect(struct i2c_client *new_client, >> LM75s. It has an ID byte of 0xaX (where X is the chip >> revision, with 1 being the only revision in existence) in >> register 7, and unused registers return 0xff rather than the >> - last read value. */ >> + last read value. >> + >> + The Analog Devices ADT75 has an additional register at 0x04 >> + for initiating oneshot captures. It is not actively used in >> + this driver but we must avoid assuming it will behave as >> + 0x05-0x07 do and return the last read value. In fact register 0x04 >> + reads the same as register 0x00. And all registers are repetitive >> + mirrored around register 0x04. >> + */ >> >> /* Unused bits */ >> conf = i2c_smbus_read_byte_data(new_client, 1); >> @@ -277,7 +287,16 @@ static int lm75_detect(struct i2c_client *new_client, >> is_lm75a = 1; >> hyst = i2c_smbus_read_byte_data(new_client, 2); >> os = i2c_smbus_read_byte_data(new_client, 3); >> - } else { /* Traditional style LM75 detection */ >> + } else { /* ADT75 detection: mirrored registers */ >> + os = i2c_smbus_read_byte_data(new_client, 3); >> + hyst = i2c_smbus_read_byte_data(new_client, 2); >> + if (i2c_smbus_read_byte_data(new_client, 7) == os >> + || i2c_smbus_read_byte_data(new_client, 11) == os >> + || i2c_smbus_read_byte_data(new_client, 15) == os) >> + is_adt75 = 1; > > This seems to be quite weak. It assumes the chip is ADT75 if any of > registers {7, 11, 15} matches register 3. We already know that on a > regular LM75, register 11 will match register 3, because the address > cycling code checks for it. So it seems to me that the code here will > always conclude that the chip is an ADT75. Dratt, I read that as a load of ands which I guess is the intent. Good spot Guenter. > > Am I missing something ? Did anyone check this code on a LM75 ? > > Thanks, > Guenter > >> + } >> + >> + if (!is_lm75a && !is_adt75) { /* Traditional style LM75 detection */ >> /* Unused addresses */ >> hyst = i2c_smbus_read_byte_data(new_client, 2); >> if (i2c_smbus_read_byte_data(new_client, 4) != hyst >> @@ -304,7 +323,10 @@ static int lm75_detect(struct i2c_client *new_client, >> return -ENODEV; >> } >> >> - strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); >> + if (!is_adt75) >> + strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); >> + else >> + strlcpy(info->type, "adt75", I2C_NAME_SIZE); >> >> return 0; >> } > > _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
