[PATCH 2.6] I2C: New hardware monitor driver: adm9240 (2nd try)
grant_lkml at dodo.com.au
Thu Apr 28 13:39:18 CEST 2005
On Thu, 28 Apr 2005 10:10:27 +0200 (CEST), "Jean Delvare" <khali at linux-fr.org> wrote:
Please forgive my grumpiness in last reply, I was annoyed at myself
for missing that 1 instead of 0 in the cold start code limits clear
>> > reg = adm9240_read_value(client, ADM9240_REG_CONFIG);
>> > adm9240_write_value(client, ADM9240_REG_CONFIG,
>> > (reg | 0x01) & 0x7f);
>> That would fail to start the measurement cycle (...)
>How that? Bit 0 will be set to 1, which starts the measurement cycle,
>exactly like your previous code did.
Need to clear bit 3, powerup = 1, as well as set bit 0, but:
control reg (40h)
7..4 writing zero harmless
3 INT_clear, power-up default = 1 stops measurement, writing zero required
2,1 writing zero harmless
0 start measurement cycle, write '1' to start measurement cycle
powerup value = 0x08: bit 3 set stops measuring cycle, waiting for
interrupt acknowledge, writing 0x01 to start is therefore correct,
however, I can change "cold start" test to (control == 0x08), which
is much more correct as the observed and datasheet power-up value
than (control & 1) NZ indicating measurement cycle is running.
temp mode reg (4bh)
7 ro lsb chip temperature, writing zero harmless
6..2 reserved, = 0, writing zero harmless
1,0 0,3 'default' interrupt mode :)
1 power up = 1 --> one shot mode (so why 0,3 called default?)
2 comparator mode, does not assert temp alarm flags
Therefore writing 0 sets mode zero and is harmless. Leaving it at
powerup default is also harmless as we not using interrupts and alarm
status is correct, comparator mode does not set alarm status for
over-temperature. Since we do not provide an accessor for this value
the driver should set it to 0 or 1 to enable over-temp alarm status.
If the driver finds the chip running no change at all is made to
control or mode.
Maybe I should wait until after 18.104.22.168 before resending patch again,
we're just clogging the works?
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