From c8d3578f8b76ebd2ed4793b365651ffe8093a675 Mon Sep 17 00:00:00 2001
From: Fenglin Wu <fenglinw@codeaurora.org>
Date: Mon, 3 Jul 2017 12:44:59 +0800
Subject: [PATCH] pwm: pwm-qpnp: Ignore changing period setting if it's not
 requested

It's not necessary to reprogram PWM period setting if only
changing PWM duty cycle.

Change-Id: I366e17a5e2f18c09ab0850d00ec08a35e0f1cb9f
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>
---
 drivers/pwm/pwm-qpnp.c | 46 +++++++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/drivers/pwm/pwm-qpnp.c b/drivers/pwm/pwm-qpnp.c
index d57bf2f3b80c..e46b1d583f40 100644
--- a/drivers/pwm/pwm-qpnp.c
+++ b/drivers/pwm/pwm-qpnp.c
@@ -317,6 +317,7 @@ struct _qpnp_pwm_config {
 	struct pwm_period_config	period;
 	int				supported_sizes;
 	int				force_pwm_size;
+	bool				update_period;
 };
 
 /* Public facing structure */
@@ -1209,30 +1210,34 @@ static int _pwm_config(struct qpnp_pwm_chip *chip,
 			duty_value / NSEC_PER_USEC;
 	qpnp_lpg_calc_pwm_value(pwm_config, period_value, duty_value);
 	rc = qpnp_lpg_save_pwm_value(chip);
-	if (rc)
-		goto out;
-	rc = qpnp_lpg_configure_pwm(chip);
-	if (rc)
-		goto out;
-	rc = qpnp_configure_pwm_control(chip);
 	if (rc)
 		goto out;
 
-	if (!rc && chip->enabled) {
-		rc = qpnp_lpg_configure_pwm_state(chip, QPNP_PWM_ENABLE);
-		if (rc) {
-			pr_err("Error in configuring pwm state, rc=%d\n", rc);
-			return rc;
-		}
+	if (pwm_config->update_period) {
+		rc = qpnp_lpg_configure_pwm(chip);
+		if (rc)
+			goto out;
+		rc = qpnp_configure_pwm_control(chip);
+		if (rc)
+			goto out;
+		if (!rc && chip->enabled) {
+			rc = qpnp_lpg_configure_pwm_state(chip,
+					QPNP_PWM_ENABLE);
+			if (rc) {
+				pr_err("Error in configuring pwm state, rc=%d\n",
+						rc);
+				return rc;
+			}
 
-		/* Enable the glitch removal after PWM is enabled */
-		rc = qpnp_lpg_glitch_removal(chip, true);
-		if (rc) {
-			pr_err("Error in enabling glitch control, rc=%d\n", rc);
-			return rc;
+			/* Enable the glitch removal after PWM is enabled */
+			rc = qpnp_lpg_glitch_removal(chip, true);
+			if (rc) {
+				pr_err("Error in enabling glitch control, rc=%d\n",
+						rc);
+				return rc;
+			}
 		}
 	}
-
 	pr_debug("duty/period=%u/%u %s: pwm_value=%d (of %d)\n",
 		 (unsigned int)duty_value, (unsigned int)period_value,
 		 (tm_lvl == LVL_USEC) ? "usec" : "nsec",
@@ -1375,12 +1380,14 @@ static int qpnp_pwm_config(struct pwm_chip *pwm_chip,
 
 	spin_lock_irqsave(&chip->lpg_lock, flags);
 
+	chip->pwm_config.update_period = false;
 	if (prev_period_us > INT_MAX / NSEC_PER_USEC ||
 			prev_period_us * NSEC_PER_USEC != period_ns) {
 		qpnp_lpg_calc_period(LVL_NSEC, period_ns, chip);
 		qpnp_lpg_save_period(chip);
 		pwm->period = period_ns;
 		chip->pwm_config.pwm_period = period_ns / NSEC_PER_USEC;
+		chip->pwm_config.update_period = true;
 	}
 
 	rc = _pwm_config(chip, LVL_NSEC, duty_ns, period_ns);
@@ -1619,6 +1626,7 @@ int pwm_config_us(struct pwm_device *pwm, int duty_us, int period_us)
 
 	spin_lock_irqsave(&chip->lpg_lock, flags);
 
+	chip->pwm_config.update_period = false;
 	if (chip->pwm_config.pwm_period != period_us) {
 		qpnp_lpg_calc_period(LVL_USEC, period_us, chip);
 		qpnp_lpg_save_period(chip);
@@ -1628,6 +1636,7 @@ int pwm_config_us(struct pwm_device *pwm, int duty_us, int period_us)
 			pwm->period = 0;
 		else
 			pwm->period = (unsigned int)period_us * NSEC_PER_USEC;
+		chip->pwm_config.update_period = true;
 	}
 
 	rc = _pwm_config(chip, LVL_USEC, duty_us, period_us);
@@ -1734,6 +1743,7 @@ static int qpnp_parse_pwm_dt_config(struct device_node *of_pwm_node,
 	qpnp_lpg_calc_period(LVL_USEC, period, chip);
 	qpnp_lpg_save_period(chip);
 	chip->pwm_config.pwm_period = period;
+	chip->pwm_config.update_period = true;
 
 	rc = _pwm_config(chip, LVL_USEC, chip->pwm_config.pwm_duty, period);