diff options
Diffstat (limited to 'Documentation')
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. |