ChangeSet 1.1938.439.47, 2005/01/06 13:55:26-08:00, khali at linux-fr.org [PATCH] I2C: Fix MAX6657/8/9 detection in lm90 I received no additional feedback about my MAX6657/8/9 detection fix. Since it was correct for the only chips I got a report for, I propose we apply it. After all, maybe people don't know they have such a chip because the detection was previously not correct. The patch below is the one I sent to the LM Sensors and Linux Kernel mailing-lists two weeks ago, unchanged. Thanks. Signed-off-by: Jean Delvare <khali at linux-fr.org> Signed-off-by: Greg Kroah-Hartman <greg at kroah.com> drivers/i2c/chips/lm90.c | 28 ++++++++++++++++++++-------- 1 files changed, 20 insertions(+), 8 deletions(-) diff -Nru a/drivers/i2c/chips/lm90.c b/drivers/i2c/chips/lm90.c --- a/drivers/i2c/chips/lm90.c 2005-01-07 14:54:33 -08:00 +++ b/drivers/i2c/chips/lm90.c 2005-01-07 14:54:33 -08:00 @@ -35,12 +35,13 @@ * Among others, it has a higher accuracy than the LM90, much like the * LM86 does. * - * This driver also supports the MAX6657 and MAX6658, sensor chips made - * by Maxim. These chips are similar to the LM86. Complete datasheet - * can be obtained at Maxim's website at: + * This driver also supports the MAX6657, MAX6658 and MAX6659 sensor + * chips made by Maxim. These chips are similar to the LM86. Complete + * datasheet can be obtained at Maxim's website at: * http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578 - * Note that there is no way to differenciate between both chips (but - * no need either). + * Note that there is no easy way to differenciate between the three + * variants. The extra address and features of the MAX6659 are not + * supported by this driver. * * Since the LM90 was the first chipset supported by this driver, most * comments will refer to this chipset, but are actually general and @@ -70,9 +71,11 @@ /* * Addresses to scan - * Address is fully defined internally and cannot be changed. + * Address is fully defined internally and cannot be changed except for + * MAX6659. * LM86, LM89, LM90, LM99, ADM1032, MAX6657 and MAX6658 have address 0x4c. * LM89-1, and LM99-1 have address 0x4d. + * MAX6659 can have address 0x4c, 0x4d or 0x4e (unsupported). */ static unsigned short normal_i2c[] = { 0x4c, 0x4d, I2C_CLIENT_END }; @@ -386,8 +389,17 @@ } } else if (man_id == 0x4D) { /* Maxim */ - if (address == 0x4C - && (reg_config1 & 0x1F) == 0 + /* + * The Maxim variants do NOT have a chip_id register. + * Reading from that address will return the last read + * value, which in our case is those of the man_id + * register. Likewise, the config1 register seems to + * lack a low nibble, so the value will be those of the + * previous read, so in our case those of the man_id + * register. + */ + if (chip_id == man_id + && (reg_config1 & 0x1F) == (man_id & 0x0F) && reg_convrate <= 0x09) { kind = max6657; }
