static struct i2c_driver foo_driver = {
.owner = THIS_MODULE,
.name = "Foo version 2.3 driver",
- .id = I2C_DRIVERID_FOO, /* from i2c-id.h, optional */
.flags = I2C_DF_NOTIFY,
.attach_adapter = &foo_attach_adapter,
.detach_client = &foo_detach_client,
The name can be chosen freely, and may be upto 40 characters long. Please
use something descriptive here.
-If used, the id should be a unique ID. The range 0xf000 to 0xffff is
-reserved for local use, and you can use one of those until you start
-distributing the driver, at which time you should contact the i2c authors
-to get your own ID(s). Note that most of the time you don't need an ID
-at all so you can just omit it.
-
Don't worry about the flags field; just put I2C_DF_NOTIFY into it. This
means that your driver will be notified when new adapters are found.
This is almost always what you want.
detection algorithm.
You do not have to use this parameter interface; but don't try to use
-function i2c_probe() (or i2c_detect()) if you don't.
+function i2c_probe() if you don't.
NOTE: If you want to write a `sensors' driver, the interface is slightly
different! See below.
-Probing classes (i2c)
----------------------
+Probing classes
+---------------
All parameters are given as lists of unsigned 16-bit integers. Lists are
terminated by I2C_CLIENT_END.
ignore: insmod parameter.
A list of pairs. The first value is a bus number (-1 for any I2C bus),
the second is the I2C address. These addresses are never probed.
- This parameter overrules 'normal' and 'probe', but not the 'force' lists.
+ This parameter overrules the 'normal_i2c' list only.
force: insmod parameter.
A list of pairs. The first value is a bus number (-1 for any I2C bus),
the second is the I2C address. A device is blindly assumed to be on
the given address, no probing is done.
+Additionally, kind-specific force lists may optionally be defined if
+the driver supports several chip kinds. They are grouped in a
+NULL-terminated list of pointers named forces, those first element if the
+generic force list mentioned above. Each additional list correspond to an
+insmod parameter of the form force_<kind>.
+
Fortunately, as a module writer, you just have to define the `normal_i2c'
parameter. The complete declaration could look like this:
/* Magic definition of all other variables and things */
I2C_CLIENT_INSMOD;
+ /* Or, if your driver supports, say, 2 kind of devices: */
+ I2C_CLIENT_INSMOD_2(foo, bar);
+
+If you use the multi-kind form, an enum will be defined for you:
+ enum chips { any_chip, foo, bar, ... }
+You can then (and certainly should) use it in the driver code.
Note that you *have* to call the defined variable `normal_i2c',
without any prefix!
-Probing classes (sensors)
--------------------------
-
-If you write a `sensors' driver, you use a slightly different interface.
-As well as I2C addresses, we have to cope with ISA addresses. Also, we
-use a enum of chip types. Don't forget to include `sensors.h'.
-
-The following lists are used internally. They are all lists of integers.
-
- normal_i2c: filled in by the module writer. Terminated by SENSORS_I2C_END.
- A list of I2C addresses which should normally be examined.
- normal_isa: filled in by the module writer. Terminated by SENSORS_ISA_END.
- A list of ISA addresses which should normally be examined.
- probe: insmod parameter. Initialize this list with SENSORS_I2C_END values.
- A list of pairs. The first value is a bus number (SENSORS_ISA_BUS for
- the ISA bus, -1 for any I2C bus), the second is the address. These
- addresses are also probed, as if they were in the 'normal' list.
- ignore: insmod parameter. Initialize this list with SENSORS_I2C_END values.
- A list of pairs. The first value is a bus number (SENSORS_ISA_BUS for
- the ISA bus, -1 for any I2C bus), the second is the I2C address. These
- addresses are never probed. This parameter overrules 'normal' and
- 'probe', but not the 'force' lists.
-
-Also used is a list of pointers to sensors_force_data structures:
- force_data: insmod parameters. A list, ending with an element of which
- the force field is NULL.
- Each element contains the type of chip and a list of pairs.
- The first value is a bus number (SENSORS_ISA_BUS for the ISA bus,
- -1 for any I2C bus), the second is the address.
- These are automatically translated to insmod variables of the form
- force_foo.
-
-So we have a generic insmod variabled `force', and chip-specific variables
-`force_CHIPNAME'.
-
-Fortunately, as a module writer, you just have to define the `normal_i2c'
-and `normal_isa' parameters, and define what chip names are used.
-The complete declaration could look like this:
- /* Scan i2c addresses 0x37, and 0x48 to 0x4f */
- static unsigned short normal_i2c[] = { 0x37, 0x48, 0x49, 0x4a, 0x4b, 0x4c,
- 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
- /* Scan ISA address 0x290 */
- static unsigned int normal_isa[] = {0x0290,SENSORS_ISA_END};
-
- /* Define chips foo and bar, as well as all module parameters and things */
- SENSORS_INSMOD_2(foo,bar);
-
-If you have one chip, you use macro SENSORS_INSMOD_1(chip), if you have 2
-you use macro SENSORS_INSMOD_2(chip1,chip2), etc. If you do not want to
-bother with chip types, you can use SENSORS_INSMOD_0.
-
-A enum is automatically defined as follows:
- enum chips { any_chip, chip1, chip2, ... }
-
-
Attaching to an adapter
-----------------------
return i2c_probe(adapter,&addr_data,&foo_detect_client);
}
-For `sensors' drivers, use the i2c_detect function instead:
-
- int foo_attach_adapter(struct i2c_adapter *adapter)
- {
- return i2c_detect(adapter,&addr_data,&foo_detect_client);
- }
-
Remember, structure `addr_data' is defined by the macros explained above,
so you do not have to define it yourself.
-The i2c_probe or i2c_detect function will call the foo_detect_client
+The i2c_probe function will call the foo_detect_client
function only for those i2c addresses that actually have a device on
them (unless a `force' parameter was used). In addition, addresses that
are already in use (by some other registered client) are skipped.
The detect client function
--------------------------
-The detect client function is called by i2c_probe or i2c_detect.
-The `kind' parameter contains 0 if this call is due to a `force'
-parameter, and -1 otherwise (for i2c_detect, it contains 0 if
-this call is due to the generic `force' parameter, and the chip type
-number if it is due to a specific `force' parameter).
+The detect client function is called by i2c_probe. The `kind' parameter
+contains -1 for a probed detection, 0 for a forced detection, or a positive
+number for a forced detection with a chip type forced.
Below, some things are only needed if this is a `sensors' driver. Those
parts are between /* SENSORS ONLY START */ and /* SENSORS ONLY END */
markers.
-This function should only return an error (any value != 0) if there is
-some reason why no more detection should be done anymore. If the
-detection just fails for this address, return 0.
+Returning an error different from -ENODEV in a detect function will cause
+the detection to stop: other addresses and adapters won't be scanned.
+This should only be done on fatal or internal errors, such as a memory
+shortage or i2c_attach_client failing.
For now, you can ignore the `flags' parameter. It is there for future use.
const char *type_name = "";
int is_isa = i2c_is_isa_adapter(adapter);
- if (is_isa) {
+ /* Do this only if the chip can additionally be found on the ISA bus
+ (hybrid chip). */
- /* If this client can't be on the ISA bus at all, we can stop now
- (call `goto ERROR0'). But for kicks, we will assume it is all
- right. */
+ if (is_isa) {
/* Discard immediately if this ISA range is already used */
if (check_region(address,FOO_EXTENT))
/* SENSORS ONLY END */
/* Try to detach the client from i2c space */
- if ((err = i2c_detach_client(client))) {
- printk("foo.o: Client deregistration failed, client not detached.\n");
+ if ((err = i2c_detach_client(client)))
return err;
- }
- /* SENSORS ONLY START */
+ /* HYBRID SENSORS CHIP ONLY START */
if i2c_is_isa_client(client)
release_region(client->addr,LM78_EXTENT);
- /* SENSORS ONLY END */
+ /* HYBRID SENSORS CHIP ONLY END */
kfree(client); /* Frees client data too, if allocated at the same time */
return 0;