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authorLinus Torvalds <torvalds@linux-foundation.org>2024-01-13 01:59:50 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2024-01-13 01:59:50 +0300
commit42bff4d0f9b9c8b669c5cef25c5116f41eb45c6b (patch)
treefe9cefffc83c2e8cb4afe8d5fbfa632691dc3e91 /Documentation
parentfef018d8199661962b5fc0f0d1501caa54b2b533 (diff)
parent7afc0e7f681e6efd6b826f003fc14c17b5093643 (diff)
downloadlinux-42bff4d0f9b9c8b669c5cef25c5116f41eb45c6b.tar.xz
Merge tag 'pwm/for-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm
Pull pwm updates from Thierry Reding: "This contains a bunch of cleanups and simplifications across the board, as well as a number of small fixes. Perhaps the most notable change here is the addition of an API that allows PWMs to be used in atomic contexts, which is useful when time- critical operations are involved, such as using a PWM to generate IR signals. Finally, I have decided to step down as PWM subsystem maintainer. Due to other responsibilities I have lately not been able to find the time that the subsystem deserves and Uwe, who has been helping out a lot for the past few years and has many things planned for the future, has kindly volunteered to take over. I have no doubt that he will be a suitable replacement" * tag 'pwm/for-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (44 commits) MAINTAINERS: pwm: Thierry steps down, Uwe takes over pwm: linux/pwm.h: fix Excess kernel-doc description warning pwm: Add pwm_apply_state() compatibility stub pwm: cros-ec: Drop documentation for dropped struct member pwm: Drop two unused API functions pwm: lpc18xx-sct: Don't modify the cached period of other PWM outputs pwm: meson: Simplify using dev_err_probe() pwm: stmpe: Silence duplicate error messages pwm: Reduce number of pointer dereferences in pwm_device_request() pwm: crc: Use consistent variable naming for driver data pwm: omap-dmtimer: Drop locking dt-bindings: pwm: ti,pwm-omap-dmtimer: Update binding for yaml media: pwm-ir-tx: Trigger edges from hrtimer interrupt context pwm: bcm2835: Allow PWM driver to be used in atomic context pwm: Make it possible to apply PWM changes in atomic context pwm: renesas: Remove unused include pwm: Replace ENOTSUPP with EOPNOTSUPP pwm: Rename pwm_apply_state() to pwm_apply_might_sleep() pwm: Stop referencing pwm->chip pwm: Update kernel doc for struct pwm_chip ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml1
-rw-r--r--Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt22
-rw-r--r--Documentation/devicetree/bindings/pwm/ti,omap-dmtimer-pwm.yaml59
-rw-r--r--Documentation/driver-api/pwm.rst17
4 files changed, 72 insertions, 27 deletions
diff --git a/Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml b/Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml
index 153e146df7d4..afcdeed4e88a 100644
--- a/Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml
+++ b/Documentation/devicetree/bindings/pwm/mediatek,pwm-disp.yaml
@@ -8,7 +8,6 @@ title: MediaTek DISP_PWM Controller
maintainers:
- Jitao Shi <jitao.shi@mediatek.com>
- - Xinlei Lee <xinlei.lee@mediatek.com>
allOf:
- $ref: pwm.yaml#
diff --git a/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt b/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt
deleted file mode 100644
index 25ecfe14c698..000000000000
--- a/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt
+++ /dev/null
@@ -1,22 +0,0 @@
-* OMAP PWM for dual-mode timers
-
-Required properties:
-- compatible: Shall contain "ti,omap-dmtimer-pwm".
-- ti,timers: phandle to PWM capable OMAP timer. See timer/ti,timer-dm.yaml for info
- about these timers.
-- #pwm-cells: Should be 3. See pwm.yaml in this directory for a description of
- the cells format.
-
-Optional properties:
-- ti,prescaler: Should be a value between 0 and 7, see the timers datasheet
-- ti,clock-source: Set dmtimer parent clock, values between 0 and 2:
- - 0x00 - high-frequency system clock (timer_sys_ck)
- - 0x01 - 32-kHz always-on clock (timer_32k_ck)
- - 0x02 - external clock (timer_ext_ck, OMAP2 only)
-
-Example:
- pwm9: dmtimer-pwm@9 {
- compatible = "ti,omap-dmtimer-pwm";
- ti,timers = <&timer9>;
- #pwm-cells = <3>;
- };
diff --git a/Documentation/devicetree/bindings/pwm/ti,omap-dmtimer-pwm.yaml b/Documentation/devicetree/bindings/pwm/ti,omap-dmtimer-pwm.yaml
new file mode 100644
index 000000000000..1e8e094aad74
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/ti,omap-dmtimer-pwm.yaml
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/ti,omap-dmtimer-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI dual mode timer PWM controller
+
+maintainers:
+ - Tony Lindgren <tony@atomide.com>
+
+description:
+ TI dual mode timer instances have an IO pin for PWM capability
+
+allOf:
+ - $ref: pwm.yaml#
+
+properties:
+ compatible:
+ const: ti,omap-dmtimer-pwm
+
+ "#pwm-cells":
+ const: 3
+
+ ti,timers:
+ description: Timer instance phandle for the PWM
+ $ref: /schemas/types.yaml#/definitions/phandle
+
+ ti,prescaler:
+ description: |
+ Legacy clock prescaler for timer. The timer counter is prescaled
+ with 2^n where n is the prescaler.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [ 0, 1, 2, 3, 4, 5, 6, 7 ]
+ deprecated: true
+
+ ti,clock-source:
+ description: |
+ Legacy clock for timer, please use assigned-clocks instead.
+ 0x00 - high-frequency system clock (timer_sys_ck)
+ 0x01 - 32-kHz always-on clock (timer_32k_ck)
+ 0x02 - external clock (timer_ext_ck, OMAP2 only)
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [ 0, 1, 2 ]
+ deprecated: true
+
+required:
+ - compatible
+ - ti,timers
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ pwm9: pwm {
+ compatible = "ti,omap-dmtimer-pwm";
+ ti,timers = <&timer9>;
+ #pwm-cells = <3>;
+ };
diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst
index bb264490a87a..3c28ccc4b611 100644
--- a/Documentation/driver-api/pwm.rst
+++ b/Documentation/driver-api/pwm.rst
@@ -41,11 +41,20 @@ the getter, devm_pwm_get() and devm_fwnode_pwm_get(), also exist.
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_might_sleep(struct pwm_device *pwm, struct pwm_state *state);
This API controls both the PWM period/duty_cycle config and the
enable/disable state.
+PWM devices can be used from atomic context, if the PWM does not sleep. You
+can check if this the case with::
+
+ bool pwm_might_sleep(struct pwm_device *pwm);
+
+If false, the PWM can also be configured from atomic context with::
+
+ int pwm_apply_atomic(struct pwm_device *pwm, struct pwm_state *state);
+
As a consumer, don't rely on the output's state for a disabled PWM. If it's
easily possible, drivers are supposed to emit the inactive state, but some
drivers cannot. If you rely on getting the inactive state, use .duty_cycle=0,
@@ -57,13 +66,13 @@ If supported by the driver, the signal can be optimized, for example to improve
EMI by phase shifting the individual channels of a chip.
The pwm_config(), pwm_enable() and pwm_disable() functions are just wrappers
-around pwm_apply_state() and should not be used if the user wants to change
+around pwm_apply_might_sleep() and should not be used if the user wants to change
several parameter at once. For example, if you see pwm_config() and
pwm_{enable,disable}() calls in the same function, this probably means you
-should switch to pwm_apply_state().
+should switch to pwm_apply_might_sleep().
The PWM user API also allows one to query the PWM state that was passed to the
-last invocation of pwm_apply_state() using pwm_get_state(). Note this is
+last invocation of pwm_apply_might_sleep() using pwm_get_state(). Note this is
different to what the driver has actually implemented if the request cannot be
satisfied exactly with the hardware in use. There is currently no way for
consumers to get the actually implemented settings.