summaryrefslogtreecommitdiffstats
path: root/Documentation/pcmcia/devicetable.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/pcmcia/devicetable.rst')
-rw-r--r--Documentation/pcmcia/devicetable.rst37
1 files changed, 37 insertions, 0 deletions
diff --git a/Documentation/pcmcia/devicetable.rst b/Documentation/pcmcia/devicetable.rst
new file mode 100644
index 000000000000..fd1d60d12ca1
--- /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"