Hi Per,
On Wed, May 25, 2011 at 12:56:01PM -0400, Per Dalén wrote:
> This patch adds detection of MAX6642 to sensors-detect.
>
> Signed-off-by: Per Dalen <per.dalen@xxxxxxxxxxxx>
> ---
>
> --- prog/detect/sensors-detect (revision 5975)
> +++ prog/detect/sensors-detect (working copy)
> @@ -848,6 +848,11 @@
> i2c_addrs => [0x2c, 0x2e, 0x2f],
> i2c_detect => sub { max6639_detect(@_); },
> }, {
> + name => "Maxim MAX6642",
> + driver => "max6642",
> + i2c_addrs => [0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e,
> 0x4f],
> + i2c_detect => sub { max6642_detect(@_); },
> + }, {
> name => "Maxim MAX6655/MAX6656",
> driver => "max6655",
> i2c_addrs => [0x18..0x1a, 0x29..0x2b, 0x4c..0x4e],
> @@ -5779,6 +5784,36 @@
> return 6;
> }
>
> +# Chip to detect: MAX6642
> +# Registers used:
> +# 0x02: Status register
> +# 0x03: Configuration register
> +# 0xfe: Manufacturer ID
> +# 0x04,0x06,0xff: No registers
> +# We use the 0x04,0x06 and 0xff addresses (unused) to improve the
> reliability.
> +# These are not real registers and will always return the last returned
> value.
> +# This isn't documented.
> +sub max6642_detect
> +{
> + my ($file, $addr) = @_;
> + my ($man_id, $conf, $status);
> +
> + $man_id = i2c_smbus_read_byte_data($file, 0xfe, NO_CACHE);
You might want to more the check for $man_id == 0x4d to here,
to avoid reading the other registers if you don't have to.
> + return if i2c_smbus_read_byte_data($file, 0x04, NO_CACHE) !=
> $man_id;
I think it would be better to read the other non-existing registers here,
because if those are real registers they are more unlikely to return 0x4d
than to return the same value as the status and configuration registers.
Something like
$man_id = i2c_smbus_read_byte_data($file, 0xfe, NO_CACHE);
return unless $man_id == 0x4d; # Maxim
return if i2c_smbus_read_byte_data($file, 0xff, NO_CACHE) != $man_id;
return if i2c_smbus_read_byte_data($file, 0x04, NO_CACHE) != $man_id;
return if i2c_smbus_read_byte_data($file, 0x06, NO_CACHE) != $man_id;
...
Thanks,
Guenter
> + $status = i2c_smbus_read_byte_data($file, 0x02, NO_CACHE);
> + return if i2c_smbus_read_byte_data($file, 0x06, NO_CACHE) !=
> $status;
> + $conf = i2c_smbus_read_byte_data($file, 0x03, NO_CACHE);
> + return if i2c_smbus_read_byte_data($file, 0xff, NO_CACHE) != $conf;
> +
> + return unless $man_id == 0x4d; # Maxim
> + # Bit 5, 3, 1 and 0 should be zero
> + return unless ($status & 0x2b) == 0x00;
> + # The 4 lower bits should be zero
> + return unless ($conf & 0x0f) == 0x00;
> +
> + return 6;
> +}
> +
> sub max6655_detect
> {
> my ($file, $addr) = @_;
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