xref: /linux/Documentation/pcmcia/devicetable.rst (revision ed32f8d42cee118b075e4372a55c7739a11094b2)
1============
2Device table
3============
4
5Matching of PCMCIA devices to drivers is done using one or more of the
6following criteria:
7
8- manufactor ID
9- card ID
10- product ID strings _and_ hashes of these strings
11- function ID
12- device function (actual and pseudo)
13
14You should use the helpers in include/pcmcia/device_id.h for generating the
15struct pcmcia_device_id[] entries which match devices to drivers.
16
17If you want to match product ID strings, you also need to pass the crc32
18hashes of the string to the macro, e.g. if you want to match the product ID
19string 1, you need to use
20
21PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
22
23If the hash is incorrect, the kernel will inform you about this in "dmesg"
24upon module initialization, and tell you of the correct hash.
25
26You can determine the hash of the product ID strings by catting the file
27"modalias" in the sysfs directory of the PCMCIA device. It generates a string
28in the following form:
29pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
30
31The hex value after "pa" is the hash of product ID string 1, after "pb" for
32string 2 and so on.
33
34Alternatively, you can use crc32hash (see tools/pcmcia/crc32hash.c)
35to determine the crc32 hash.  Simply pass the string you want to evaluate
36as argument to this program, e.g.:
37$ tools/pcmcia/crc32hash "Dual Speed"
38