-
-The sensors sysctl/proc interface
-=================================
-
-This section only applies if you write `sensors' drivers.
-
-Each sensors driver creates a directory in /proc/sys/dev/sensors for each
-registered client. The directory is called something like foo-i2c-4-65.
-The sensors module helps you to do this as easily as possible.
-
-The template
-------------
-
-You will need to define a ctl_table template. This template will automatically
-be copied to a newly allocated structure and filled in where necessary when
-you call sensors_register_entry.
-
-First, I will give an example definition.
- static ctl_table foo_dir_table_template[] = {
- { FOO_SYSCTL_FUNC1, "func1", NULL, 0, 0644, NULL, &i2c_proc_real,
- &i2c_sysctl_real,NULL,&foo_func },
- { FOO_SYSCTL_FUNC2, "func2", NULL, 0, 0644, NULL, &i2c_proc_real,
- &i2c_sysctl_real,NULL,&foo_func },
- { FOO_SYSCTL_DATA, "data", NULL, 0, 0644, NULL, &i2c_proc_real,
- &i2c_sysctl_real,NULL,&foo_data },
- { 0 }
- };
-
-In the above example, three entries are defined. They can either be
-accessed through the /proc interface, in the /proc/sys/dev/sensors/*
-directories, as files named func1, func2 and data, or alternatively
-through the sysctl interface, in the appropriate table, with identifiers
-FOO_SYSCTL_FUNC1, FOO_SYSCTL_FUNC2 and FOO_SYSCTL_DATA.
-
-The third, sixth and ninth parameters should always be NULL, and the
-fourth should always be 0. The fifth is the mode of the /proc file;
-0644 is safe, as the file will be owned by root:root.
-
-The seventh and eighth parameters should be &i2c_proc_real and
-&i2c_sysctl_real if you want to export lists of reals (scaled
-integers). You can also use your own function for them, as usual.
-Finally, the last parameter is the call-back to gather the data
-(see below) if you use the *_proc_real functions.
-
-
-Gathering the data
-------------------
-
-The call back functions (foo_func and foo_data in the above example)
-can be called in several ways; the operation parameter determines
-what should be done:
-
- * If operation == SENSORS_PROC_REAL_INFO, you must return the
- magnitude (scaling) in nrels_mag;
- * If operation == SENSORS_PROC_REAL_READ, you must read information
- from the chip and return it in results. The number of integers
- to display should be put in nrels_mag;
- * If operation == SENSORS_PROC_REAL_WRITE, you must write the
- supplied information to the chip. nrels_mag will contain the number
- of integers, results the integers themselves.
-
-The *_proc_real functions will display the elements as reals for the
-/proc interface. If you set the magnitude to 2, and supply 345 for
-SENSORS_PROC_REAL_READ, it would display 3.45; and if the user would
-write 45.6 to the /proc file, it would be returned as 4560 for
-SENSORS_PROC_REAL_WRITE. A magnitude may even be negative!
-
-An example function:
-
- /* FOO_FROM_REG and FOO_TO_REG translate between scaled values and
- register values. Note the use of the read cache. */
- void foo_in(struct i2c_client *client, int operation, int ctl_name,
- int *nrels_mag, long *results)
- {
- struct foo_data *data = client->data;
- int nr = ctl_name - FOO_SYSCTL_FUNC1; /* reduce to 0 upwards */
-
- if (operation == SENSORS_PROC_REAL_INFO)
- *nrels_mag = 2;
- else if (operation == SENSORS_PROC_REAL_READ) {
- /* Update the readings cache (if necessary) */
- foo_update_client(client);
- /* Get the readings from the cache */
- results[0] = FOO_FROM_REG(data->foo_func_base[nr]);
- results[1] = FOO_FROM_REG(data->foo_func_more[nr]);
- results[2] = FOO_FROM_REG(data->foo_func_readonly[nr]);
- *nrels_mag = 2;
- } else if (operation == SENSORS_PROC_REAL_WRITE) {
- if (*nrels_mag >= 1) {
- /* Update the cache */
- data->foo_base[nr] = FOO_TO_REG(results[0]);
- /* Update the chip */
- foo_write_value(client,FOO_REG_FUNC_BASE(nr),data->foo_base[nr]);
- }
- if (*nrels_mag >= 2) {
- /* Update the cache */
- data->foo_more[nr] = FOO_TO_REG(results[1]);
- /* Update the chip */
- foo_write_value(client,FOO_REG_FUNC_MORE(nr),data->foo_more[nr]);
- }
- }
- }
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