pwm: Standardize document format

Each text file under Documentation follows a different format. Some
don't even have titles!

Change its representation to follow the adopted standard, using ReST
markup for it to be parseable by Sphinx:

- mark document title;
- mark literal blocks;
- better format the parameters.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Documentation/pwm.txt

@@ -1,4 +1,6 @@
+======================================
 Pulse Width Modulation (PWM) interface
+======================================
 
 This provides an overview about the Linux PWM interface
 
@@ -16,7 +18,7 @@ Users of the legacy PWM API use unique IDs to refer to PWM devices.
 
 Instead of referring to a PWM device via its unique ID, board setup code
 should instead register a static mapping that can be used to match PWM
-consumers to providers, as given in the following example:
+consumers to providers, as given in the following example::
 
 	static struct pwm_lookup board_pwm_lookup[] = {
 		PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL,
@@ -40,7 +42,7 @@ New users should use the pwm_get() function and pass to it the consumer
 device or a consumer name. pwm_put() is used to free the PWM device. Managed
 variants of these functions, devm_pwm_get() and devm_pwm_put(), also exist.
 
-After being requested, a PWM has to be configured using:
+After being requested, a PWM has to be configured using::
 
 	int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
 
@@ -72,11 +74,14 @@ interface is provided to use the PWMs from userspace. It is exposed at
 pwmchipN, where N is the base of the PWM chip. Inside the directory you
 will find:
 
-npwm - The number of PWM channels this chip supports (read-only).
+  npwm
+    The number of PWM channels this chip supports (read-only).
 
-export - Exports a PWM channel for use with sysfs (write-only).
+  export
+    Exports a PWM channel for use with sysfs (write-only).
 
-unexport - Unexports a PWM channel from sysfs (write-only).
+  unexport
+   Unexports a PWM channel from sysfs (write-only).
 
 The PWM channels are numbered using a per-chip index from 0 to npwm-1.
 
@@ -84,21 +89,26 @@ When a PWM channel is exported a pwmX directory will be created in the
 pwmchipN directory it is associated with, where X is the number of the
 channel that was exported. The following properties will then be available:
 
-period - The total period of the PWM signal (read/write).
+  period
+    The total period of the PWM signal (read/write).
     Value is in nanoseconds and is the sum of the active and inactive
     time of the PWM.
 
-duty_cycle - The active time of the PWM signal (read/write).
+  duty_cycle
+    The active time of the PWM signal (read/write).
     Value is in nanoseconds and must be less than the period.
 
-polarity - Changes the polarity of the PWM signal (read/write).
+  polarity
+    Changes the polarity of the PWM signal (read/write).
     Writes to this property only work if the PWM chip supports changing
     the polarity. The polarity can only be changed if the PWM is not
     enabled. Value is the string "normal" or "inversed".
 
-enable - Enable/disable the PWM signal (read/write).
+  enable
-	0 - disabled
+    Enable/disable the PWM signal (read/write).
-	1 - enabled
+
+	- 0 - disabled
+	- 1 - enabled
 
 Implementing a PWM driver
 -------------------------