1 /* SPDX-License-Identifier: GPL-2.0 */
12  * enum pwm_polarity - polarity of a PWM signal
13  * @PWM_POLARITY_NORMAL: a high signal for the duration of the duty-
14  * cycle, followed by a low signal for the remainder of the pulse
16  * @PWM_POLARITY_INVERSED: a low signal for the duration of the duty-
17  * cycle, followed by a high signal for the remainder of the pulse
26  * struct pwm_args - board-dependent PWM arguments
30  * This structure describes board-dependent arguments attached to a PWM
49  * struct pwm_state - state of a PWM channel
51  * @duty_cycle: PWM duty cycle (in nanoseconds)
68  * struct pwm_device - PWM channel object
71  * @hwpwm: per-chip relative index of the PWM device
89  * pwm_get_state() - retrieve the current PWM state
101 	*state = pwm->state;  in pwm_get_state()
143 	*args = pwm->args;  in pwm_get_args()
147  * pwm_init_state() - prepare a new state to be applied with pwm_apply_might_sleep()
154  * and polarity fields with the reference values defined in pwm->args.
155  * Once the function returns, you can adjust the ->enabled and ->duty_cycle
158  * ->duty_cycle is initially set to zero to avoid cases where the current
159  * ->duty_cycle value exceed the pwm_args->period one, which would trigger
160  * an error if the user calls pwm_apply_might_sleep() without adjusting ->duty_cycle
174 	state->period = args.period;  in pwm_init_state()
175 	state->polarity = args.polarity;  in pwm_init_state()
176 	state->duty_cycle = 0;  in pwm_init_state()
177 	state->usage_power = false;  in pwm_init_state()
181  * pwm_get_relative_duty_cycle() - Get a relative duty cycle value
182  * @state: PWM state to extract the duty cycle from
183  * @scale: target scale of the relative duty cycle
185  * This functions converts the absolute duty cycle stored in @state (expressed
191  * duty = pwm_get_relative_duty_cycle(&state, 100);
196 	if (!state->period)  in pwm_get_relative_duty_cycle()
199 	return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale,  in pwm_get_relative_duty_cycle()
200 				     state->period);  in pwm_get_relative_duty_cycle()
204  * pwm_set_relative_duty_cycle() - Set a relative duty cycle value
206  * @duty_cycle: relative duty cycle value
209  * This functions converts a relative into an absolute duty cycle (expressed
210  * in nanoseconds), and puts the result in state->duty_cycle.
212  * For example if you want to configure a 50% duty cycle, call:
218  * This functions returns -EINVAL if @duty_cycle and/or @scale are
226 		return -EINVAL;  in pwm_set_relative_duty_cycle()
228 	state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle *  in pwm_set_relative_duty_cycle()
229 						  state->period,  in pwm_set_relative_duty_cycle()
236  * struct pwm_capture - PWM capture data
238  * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
246  * struct pwm_ops - PWM controller operations
267  * struct pwm_chip - abstract a PWM controller
275  * @atomic: can the driver's ->apply() be called in atomic context
301  * pwm_config() - change a PWM device configuration
304  * @period_ns: duration (in nanoseconds) of one cycle
314 		return -EINVAL;  in pwm_config()
317 		return -EINVAL;  in pwm_config()
329  * pwm_enable() - start a PWM output toggling
339 		return -EINVAL;  in pwm_enable()
350  * pwm_disable() - stop a PWM output toggling
369  * pwm_might_sleep() - is pwm_apply_atomic() supported?
376 	return !pwm->chip->atomic;  in pwm_might_sleep()
416 	return -EOPNOTSUPP;  in pwm_apply_might_sleep()
422 	return -EOPNOTSUPP;  in pwm_apply_atomic()
427 	return -EOPNOTSUPP;  in pwm_adjust_config()
434 	return -EINVAL;  in pwm_config()
440 	return -EINVAL;  in pwm_enable()
452 	return -EINVAL;  in pwm_capture()
457 	return -EINVAL;  in pwmchip_add()
462 	return -EINVAL;  in pwmchip_remove()
467 	return -EINVAL;  in devm_pwmchip_add()
475 	return ERR_PTR(-ENODEV);  in pwm_request_from_chip()
482 	return ERR_PTR(-ENODEV);  in pwm_get()
494 	return ERR_PTR(-ENODEV);  in devm_pwm_get()
502 	return ERR_PTR(-ENODEV);  in devm_fwnode_pwm_get()
532 	state.polarity = pwm->args.polarity;  in pwm_apply_args()
533 	state.period = pwm->args.period;  in pwm_apply_args()
539 /* only for backwards-compatibility, new code should not use this */