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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-13 11:49:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-13 11:49:52 -0700
commit38f7d2da4e39d454f2cb3e7c1ae35afde3d61123 (patch)
tree159ae37207d3fa86cf8f8c06f93f7483e0fdc976 /Documentation
parentdc087d1ef1485363c21b8d781869eb8076342adf (diff)
parent5ec8c48a6235175f7ff59ed1acbe91d4d0398026 (diff)
Merge tag 'pwm/for-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding: "This release cycle's changes include mostly updates and cleanups to existing drivers along with a few cleanups to the core, documentation and device tree bindings" * tag 'pwm/for-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: pwm: cros-ec: Fix transposed param settings pwm: meson: Improve PWM calculation precision dt-bindings: pwm: meson: Add compatible for gxbb ao PWMs pwm: meson: Add compatible for the gxbb ao PWMs pwm: sun4i: Drop legacy callbacks pwm: sun4i: Switch to atomic PWM pwm: sun4i: Improve hardware read out pwm: hibvt: Constify hibvt_pwm_ops pwm: Silently error out on EPROBE_DEFER pwm: Standardize document format pwm: bfin: Remove unneeded error message dt-bindings: pwm: Update STM32 timers clock names dt-bindings: pwm: Add R-Car M3-W device tree bindings pwm: tegra: Set maximum pwm clock source per SoC tapeout
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/pwm/pwm-meson.txt4
-rw-r--r--Documentation/devicetree/bindings/pwm/pwm-stm32.txt2
-rw-r--r--Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt1
-rw-r--r--Documentation/pwm.txt46
4 files changed, 33 insertions, 20 deletions
diff --git a/Documentation/devicetree/bindings/pwm/pwm-meson.txt b/Documentation/devicetree/bindings/pwm/pwm-meson.txt
index 5376a4468cb6..5b07bebbf6f7 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-meson.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm-meson.txt
@@ -2,7 +2,9 @@ Amlogic Meson PWM Controller
============================
Required properties:
-- compatible: Shall contain "amlogic,meson8b-pwm" or "amlogic,meson-gxbb-pwm".
+- compatible: Shall contain "amlogic,meson8b-pwm"
+ or "amlogic,meson-gxbb-pwm"
+ or "amlogic,meson-gxbb-ao-pwm"
- #pwm-cells: Should be 3. See pwm.txt in this directory for a description of
the cells format.
diff --git a/Documentation/devicetree/bindings/pwm/pwm-stm32.txt b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
index 6dd040363e5e..3e6d55018d7a 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm-stm32.txt
@@ -24,7 +24,7 @@ Example:
compatible = "st,stm32-timers";
reg = <0x40010000 0x400>;
clocks = <&rcc 0 160>;
- clock-names = "clk_int";
+ clock-names = "int";
pwm {
compatible = "st,stm32-pwm";
diff --git a/Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt b/Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt
index d6de64335022..7e94b802395d 100644
--- a/Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt
+++ b/Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt
@@ -8,6 +8,7 @@ Required Properties:
- "renesas,pwm-r8a7791": for R-Car M2-W
- "renesas,pwm-r8a7794": for R-Car E2
- "renesas,pwm-r8a7795": for R-Car H3
+ - "renesas,pwm-r8a7796": for R-Car M3-W
- reg: base address and length of the registers block for the PWM.
- #pwm-cells: should be 2. See pwm.txt in this directory for a description of
the cells format.
diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
index 789b27c6ec99..8fbf0aa3ba2d 100644
--- a/Documentation/pwm.txt
+++ b/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,
@@ -40,9 +42,9 @@ 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);
+ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
This API controls both the PWM period/duty_cycle config and the
enable/disable 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).
- Value is in nanoseconds and is the sum of the active and inactive
- time of the PWM.
+ 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).
- Value is in nanoseconds and must be less than the period.
+ 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).
- 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".
+ 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).
- 0 - disabled
- 1 - enabled
+ enable
+ Enable/disable the PWM signal (read/write).
+
+ - 0 - disabled
+ - 1 - enabled
Implementing a PWM driver
-------------------------