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diff --git a/Documentation/pcmcia/devicetable.rst b/Documentation/pcmcia/devicetable.rst new file mode 100644 index 000000000..fd1d60d12 --- /dev/null +++ b/Documentation/pcmcia/devicetable.rst @@ -0,0 +1,37 @@ +============ +Device table +============ + +Matching of PCMCIA devices to drivers is done using one or more of the +following criteria: + +- manufactor ID +- card ID +- product ID strings _and_ hashes of these strings +- function ID +- device function (actual and pseudo) + +You should use the helpers in include/pcmcia/device_id.h for generating the +struct pcmcia_device_id[] entries which match devices to drivers. + +If you want to match product ID strings, you also need to pass the crc32 +hashes of the string to the macro, e.g. if you want to match the product ID +string 1, you need to use + +PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)), + +If the hash is incorrect, the kernel will inform you about this in "dmesg" +upon module initialization, and tell you of the correct hash. + +You can determine the hash of the product ID strings by catting the file +"modalias" in the sysfs directory of the PCMCIA device. It generates a string +in the following form: +pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000 + +The hex value after "pa" is the hash of product ID string 1, after "pb" for +string 2 and so on. + +Alternatively, you can use crc32hash (see tools/pcmcia/crc32hash.c) +to determine the crc32 hash. Simply pass the string you want to evaluate +as argument to this program, e.g.: +$ tools/pcmcia/crc32hash "Dual Speed" |