diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/device-drivers.tmpl | 27 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/pwm/lpc1850-sct-pwm.txt | 20 |
2 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index abba93f9d64a..1d6008d51b55 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl @@ -490,4 +490,31 @@ X!Ilib/fonts/fonts.c !Edrivers/hsi/hsi.c </chapter> + <chapter id="pwm"> + <title>Pulse-Width Modulation (PWM)</title> + <para> + Pulse-width modulation is a modulation technique primarily used to + control power supplied to electrical devices. + </para> + <para> + The PWM framework provides an abstraction for providers and consumers + of PWM signals. A controller that provides one or more PWM signals is + registered as <structname>struct pwm_chip</structname>. Providers are + expected to embed this structure in a driver-specific structure. This + structure contains fields that describe a particular chip. + </para> + <para> + A chip exposes one or more PWM signal sources, each of which exposed + as a <structname>struct pwm_device</structname>. Operations can be + performed on PWM devices to control the period, duty cycle, polarity + and active state of the signal. + </para> + <para> + Note that PWM devices are exclusive resources: they can always only be + used by one consumer at a time. + </para> +!Iinclude/linux/pwm.h +!Edrivers/pwm/core.c + </chapter> + </book> diff --git a/Documentation/devicetree/bindings/pwm/lpc1850-sct-pwm.txt b/Documentation/devicetree/bindings/pwm/lpc1850-sct-pwm.txt new file mode 100644 index 000000000000..36e49d4325cd --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/lpc1850-sct-pwm.txt @@ -0,0 +1,20 @@ +* NXP LPC18xx State Configurable Timer - Pulse Width Modulator driver + +Required properties: + - compatible: Should be "nxp,lpc1850-sct-pwm" + - reg: Should contain physical base address and length of pwm registers. + - clocks: Must contain an entry for each entry in clock-names. + See ../clock/clock-bindings.txt for details. + - clock-names: Must include the following entries. + - pwm: PWM operating clock. + - #pwm-cells: Should be 3. See pwm.txt in this directory for the description + of the cells format. + +Example: + pwm: pwm@40000000 { + compatible = "nxp,lpc1850-sct-pwm"; + reg = <0x40000000 0x1000>; + clocks =<&ccu1 CLK_CPU_SCT>; + clock-names = "pwm"; + #pwm-cells = <3>; + }; |