diff options
Diffstat (limited to 'Documentation/i2c/writing-clients')
-rw-r--r-- | Documentation/i2c/writing-clients | 68 |
1 files changed, 15 insertions, 53 deletions
diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 43d7928056ae..97e138cbb2a9 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients | |||
@@ -155,8 +155,8 @@ NOTE: If you want to write a `sensors' driver, the interface is slightly | |||
155 | 155 | ||
156 | 156 | ||
157 | 157 | ||
158 | Probing classes (i2c) | 158 | Probing classes |
159 | --------------------- | 159 | --------------- |
160 | 160 | ||
161 | All parameters are given as lists of unsigned 16-bit integers. Lists are | 161 | All parameters are given as lists of unsigned 16-bit integers. Lists are |
162 | terminated by I2C_CLIENT_END. | 162 | terminated by I2C_CLIENT_END. |
@@ -171,12 +171,18 @@ The following lists are used internally: | |||
171 | ignore: insmod parameter. | 171 | ignore: insmod parameter. |
172 | A list of pairs. The first value is a bus number (-1 for any I2C bus), | 172 | A list of pairs. The first value is a bus number (-1 for any I2C bus), |
173 | the second is the I2C address. These addresses are never probed. | 173 | the second is the I2C address. These addresses are never probed. |
174 | This parameter overrules 'normal' and 'probe', but not the 'force' lists. | 174 | This parameter overrules the 'normal_i2c' list only. |
175 | force: insmod parameter. | 175 | force: insmod parameter. |
176 | A list of pairs. The first value is a bus number (-1 for any I2C bus), | 176 | A list of pairs. The first value is a bus number (-1 for any I2C bus), |
177 | the second is the I2C address. A device is blindly assumed to be on | 177 | the second is the I2C address. A device is blindly assumed to be on |
178 | the given address, no probing is done. | 178 | the given address, no probing is done. |
179 | 179 | ||
180 | Additionally, kind-specific force lists may optionally be defined if | ||
181 | the driver supports several chip kinds. They are grouped in a | ||
182 | NULL-terminated list of pointers named forces, those first element if the | ||
183 | generic force list mentioned above. Each additional list correspond to an | ||
184 | insmod parameter of the form force_<kind>. | ||
185 | |||
180 | Fortunately, as a module writer, you just have to define the `normal_i2c' | 186 | Fortunately, as a module writer, you just have to define the `normal_i2c' |
181 | parameter. The complete declaration could look like this: | 187 | parameter. The complete declaration could look like this: |
182 | 188 | ||
@@ -186,61 +192,17 @@ parameter. The complete declaration could look like this: | |||
186 | 192 | ||
187 | /* Magic definition of all other variables and things */ | 193 | /* Magic definition of all other variables and things */ |
188 | I2C_CLIENT_INSMOD; | 194 | I2C_CLIENT_INSMOD; |
195 | /* Or, if your driver supports, say, 2 kind of devices: */ | ||
196 | I2C_CLIENT_INSMOD_2(foo, bar); | ||
197 | |||
198 | If you use the multi-kind form, an enum will be defined for you: | ||
199 | enum chips { any_chip, foo, bar, ... } | ||
200 | You can then (and certainly should) use it in the driver code. | ||
189 | 201 | ||
190 | Note that you *have* to call the defined variable `normal_i2c', | 202 | Note that you *have* to call the defined variable `normal_i2c', |
191 | without any prefix! | 203 | without any prefix! |
192 | 204 | ||
193 | 205 | ||
194 | Probing classes (sensors) | ||
195 | ------------------------- | ||
196 | |||
197 | If you write a `sensors' driver, you use a slightly different interface. | ||
198 | Also, we use a enum of chip types. Don't forget to include `sensors.h'. | ||
199 | |||
200 | The following lists are used internally. They are all lists of integers. | ||
201 | |||
202 | normal_i2c: filled in by the module writer. Terminated by I2C_CLIENT_END. | ||
203 | A list of I2C addresses which should normally be examined. | ||
204 | probe: insmod parameter. Initialize this list with I2C_CLIENT_END values. | ||
205 | A list of pairs. The first value is a bus number (ANY_I2C_BUS for any | ||
206 | I2C bus), the second is the address. These addresses are also probed, | ||
207 | as if they were in the 'normal' list. | ||
208 | ignore: insmod parameter. Initialize this list with I2C_CLIENT_END values. | ||
209 | A list of pairs. The first value is a bus number (ANY_I2C_BUS for any | ||
210 | I2C bus), the second is the I2C address. These addresses are never | ||
211 | probed. This parameter overrules 'normal' and 'probe', but not the | ||
212 | 'force' lists. | ||
213 | |||
214 | Also used is a list of pointers to sensors_force_data structures: | ||
215 | force_data: insmod parameters. A list, ending with an element of which | ||
216 | the force field is NULL. | ||
217 | Each element contains the type of chip and a list of pairs. | ||
218 | The first value is a bus number (ANY_I2C_BUS for any I2C bus), the | ||
219 | second is the address. | ||
220 | These are automatically translated to insmod variables of the form | ||
221 | force_foo. | ||
222 | |||
223 | So we have a generic insmod variabled `force', and chip-specific variables | ||
224 | `force_CHIPNAME'. | ||
225 | |||
226 | Fortunately, as a module writer, you just have to define the `normal_i2c' | ||
227 | parameter, and define what chip names are used. The complete declaration | ||
228 | could look like this: | ||
229 | /* Scan i2c addresses 0x37, and 0x48 to 0x4f */ | ||
230 | static unsigned short normal_i2c[] = { 0x37, 0x48, 0x49, 0x4a, 0x4b, 0x4c, | ||
231 | 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; | ||
232 | |||
233 | /* Define chips foo and bar, as well as all module parameters and things */ | ||
234 | SENSORS_INSMOD_2(foo,bar); | ||
235 | |||
236 | If you have one chip, you use macro SENSORS_INSMOD_1(chip), if you have 2 | ||
237 | you use macro SENSORS_INSMOD_2(chip1,chip2), etc. If you do not want to | ||
238 | bother with chip types, you can use SENSORS_INSMOD_0. | ||
239 | |||
240 | A enum is automatically defined as follows: | ||
241 | enum chips { any_chip, chip1, chip2, ... } | ||
242 | |||
243 | |||
244 | Attaching to an adapter | 206 | Attaching to an adapter |
245 | ----------------------- | 207 | ----------------------- |
246 | 208 | ||