[PATCH v3 2/6] hwmon: pwm-fan: Simplify enable/disable check

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Instead of comparing the current to the new pwm duty to decide whether to
enable the PWM, use a dedicated flag. Also apply the new PWM duty in any
case. This is a preparation to enable/disable the regulator dynamically.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
 drivers/hwmon/pwm-fan.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 458914d01155..2b7b26ab9b88 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -29,10 +29,13 @@ struct pwm_fan_tach {
 };
 
 struct pwm_fan_ctx {
+	struct device *dev;
+
 	struct mutex lock;
 	struct pwm_device *pwm;
 	struct pwm_state pwm_state;
 	struct regulator *reg_en;
+	bool enabled;
 
 	int tach_count;
 	struct pwm_fan_tach *tachs;
@@ -85,14 +88,21 @@ static void sample_timer(struct timer_list *t)
 static int pwm_fan_power_on(struct pwm_fan_ctx *ctx)
 {
 	struct pwm_state *state = &ctx->pwm_state;
-	unsigned long period;
 	int ret;
 
-	period = state->period;
-	state->duty_cycle = DIV_ROUND_UP(ctx->pwm_value * (period - 1), MAX_PWM);
+	if (ctx->enabled)
+		return 0;
+
 	state->enabled = true;
 	ret = pwm_apply_state(ctx->pwm, state);
+	if (ret) {
+		dev_err(ctx->dev, "failed to enable PWM\n");
+		goto err;
+	}
 
+	ctx->enabled = true;
+
+err:
 	return ret;
 }
 
@@ -100,26 +110,36 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx)
 {
 	struct pwm_state state;
 
+	if (!ctx->enabled)
+		return 0;
+
 	state.enabled = false;
 	state.duty_cycle = 0;
 	pwm_apply_state(ctx->pwm, &state);
 
+	ctx->enabled = false;
+
 	return 0;
 }
 
 static int  __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
 {
+	struct pwm_state *state = &ctx->pwm_state;
+	unsigned long period;
 	int ret = 0;
 
 	mutex_lock(&ctx->lock);
-	if (ctx->pwm_value == pwm)
-		goto exit_set_pwm_err;
 
-	if (pwm > 0)
+	if (pwm > 0) {
+		period = state->period;
+		state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
+		ret = pwm_apply_state(ctx->pwm, state);
+		if (ret)
+			goto exit_set_pwm_err;
 		ret = pwm_fan_power_on(ctx);
-	else
+	} else {
 		ret = pwm_fan_power_off(ctx);
-
+	}
 	if (!ret)
 		ctx->pwm_value = pwm;
 
@@ -326,6 +346,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
 
 	mutex_init(&ctx->lock);
 
+	ctx->dev = &pdev->dev;
 	ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
 	if (IS_ERR(ctx->pwm))
 		return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
-- 
2.25.1