pwm: Implement tracing for .get_state() and .apply_state()

This allows to log all calls to the driver's lowlevel functions which
simplifies debugging in some cases.

Signed-off-by: Uwe Kleine-König <[e-mail]>
Reviewed-by: Steven Rostedt (VMware) <[e-mail]>
Signed-off-by: Thierry Reding <[e-mail]>

drivers/pwm/core.c

···
 
 #include <dt-bindings/pwm/pwm.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/pwm.h>
+
 #define MAX_PWMS 1024
 
 static DEFINE_MUTEX(pwm_lookup_lock);
···
 		}
 	}
 
-	if (pwm->chip->ops->get_state)
+	if (pwm->chip->ops->get_state) {
 		pwm->chip->ops->get_state(pwm->chip, pwm, &pwm->state);
+		trace_pwm_get(pwm, &pwm->state);
+	}
 
 	set_bit(PWMF_REQUESTED, &pwm->flags);
 	pwm->label = label;
···
 		err = chip->ops->apply(chip, pwm, state);
 		if (err)
 			return err;
+
+		trace_pwm_apply(pwm, state);
 
 		pwm->state = *state;
 	} else {

include/trace/events/pwm.h

···
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pwm
+
+#if !defined(_TRACE_PWM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PWM_H
+
+#include <linux/pwm.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(pwm,
+
+	TP_PROTO(struct pwm_device *pwm, const struct pwm_state *state),
+
+	TP_ARGS(pwm, state),
+
+	TP_STRUCT__entry(
+		__field(struct pwm_device *, pwm)
+		__field(u64, period)
+		__field(u64, duty_cycle)
+		__field(enum pwm_polarity, polarity)
+		__field(bool, enabled)
+	),
+
+	TP_fast_assign(
+		__entry->pwm = pwm;
+		__entry->period = state->period;
+		__entry->duty_cycle = state->duty_cycle;
+		__entry->polarity = state->polarity;
+		__entry->enabled = state->enabled;
+	),
+
+	TP_printk("%p: period=%llu duty_cycle=%llu polarity=%d enabled=%d",
+		  __entry->pwm, __entry->period, __entry->duty_cycle,
+		  __entry->polarity, __entry->enabled)
+
+);
+
+DEFINE_EVENT(pwm, pwm_apply,
+
+	TP_PROTO(struct pwm_device *pwm, const struct pwm_state *state),
+
+	TP_ARGS(pwm, state)
+
+);
+
+DEFINE_EVENT(pwm, pwm_get,
+
+	TP_PROTO(struct pwm_device *pwm, const struct pwm_state *state),
+
+	TP_ARGS(pwm, state)
+
+);
+
+#endif /* _TRACE_PWM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>