drivers: pwm_shim: correct api argument inconsistency

Correct the argument definition inconsistency for the set
value API. To be consistent with other pwm sub drivers, the
on and off arguments for the set value api are re-defined.

On: how far (number of timer count) from the beginning of a PWM
    cycle the PWM pin will be asserted.
Off:how far (number of timer count) from the beginning of a PWM
    cycle the PWM pin will be de-asserted.

Jira: ZEP-642

Change-Id: I7b39f98f1935fc3499fb36dd813abed62b86c1e7
Signed-off-by: Baohong Liu <[email protected]>

Author: bliu11-intel

drivers/pwm/pwm_qmsi.c

@@ -158,32 +158,35 @@ static int __set_one_port(struct device *dev, qm_pwm_t id, uint32_t pwm,
 }
 
 /*
- * Set the duration for on/off timer of PWM.
+ * Set the time to assert and de-assert the PWM pin.
  *
- * This sets the duration for the pin to low or high.
+ * This sets the duration for the pin to stay low or high.
  *
- * Assumes a nominal system clock of 32MHz, each count of on/off represents
- * 31.25ns (e.g. on == 2 means the pin stays high for 62.5ns).
- * The duration of 1 count depends on system clock. Refer to the hardware
- * manual for more information.
+ * For example, with a nominal system clock of 32MHz, each count of on/off
+ * represents 31.25ns (e.g. off == 2 means the pin is to be de-asserted at
+ * 62.5ns from the beginning of a PWM cycle). The duration of 1 count depends
+ * on system clock. Refer to the hardware manual for more information.
  *
  * Parameters
- * dev: Device struct
+ * dev: Pointer to PWM device structure
  * access_op: whether to set one pin or all
- * pwm: Which PWM port to set
- * on: Duration for pin to stay high (must be >= 2)
- * off: Duration for pin to stay low (must be >= 2)
+ * pwm: PWM port number to set
+ * on: How far (in timer count) from the beginning of a PWM cycle the PWM
+ *     pin should be asserted. Must be zero, since PWM from Quark MCU always
+ *     starts from high.
+ * off: How far (in timer count) from the beginning of a PWM cycle the PWM
+ *	pin should be de-asserted.
  *
- * return 0, -ENOTSUP
+ * return 0, or negative errno code
  */
 static int pwm_qmsi_set_values(struct device *dev, int access_op,
-				  uint32_t pwm, uint32_t on, uint32_t off)
+			       uint32_t pwm, uint32_t on, uint32_t off)
 {
-	int i;
+	uint32_t *channel_period = dev->config->config_info;
+	int i, high, low;
 
-	if (off == 0) {
-		on--;
-		off = 1;
+	if (on) {
+		return -EINVAL;
 	}
 
 	switch (access_op) {
@@ -192,13 +195,40 @@ static int pwm_qmsi_set_values(struct device *dev, int access_op,
 		if (pwm >= CONFIG_PWM_QMSI_NUM_PORTS) {
 			return -EIO;
 		}
-		return __set_one_port(dev, QM_PWM_0, pwm, on, off);
+
+		high = off;
+		low = channel_period[pwm] - off;
+
+		if (off >= channel_period[pwm]) {
+			high = channel_period[pwm] - 1;
+			low = 1;
+		}
+
+		if (off == 0) {
+			high = 1;
+			low = channel_period[pwm] - 1;
+		}
+
+		return __set_one_port(dev, QM_PWM_0, pwm, high, low);
 
 	case PWM_ACCESS_ALL:
 		for (i = 0; i < CONFIG_PWM_QMSI_NUM_PORTS; i++) {
-			__set_one_port(dev, QM_PWM_0, i, on, off);
+			high = off;
+			low = channel_period[i] - off;
+
+			if (off >= channel_period[i]) {
+				high = channel_period[i] - 1;
+				low = 1;
+			}
+
+			if (off == 0) {
+				high = 1;
+				low = channel_period[i] - 1;
+			}
+
+			return __set_one_port(dev, QM_PWM_0, i, high, low);
 		}
-	break;
+		break;
 	default:
 		return -ENOTSUP;
 	}
@@ -208,7 +238,7 @@ static int pwm_qmsi_set_values(struct device *dev, int access_op,
 }
 
 static int pwm_qmsi_set_period(struct device *dev, int access_op,
-				 uint32_t pwm, uint32_t period)
+			       uint32_t pwm, uint32_t period)
 {
 	uint32_t *channel_period = dev->config->config_info;
 	int ret_val = 0;
@@ -295,12 +325,23 @@ static int pwm_qmsi_set_duty_cycle(struct device *dev, int access_op,
 	return 0;
 }
 
+static int pwm_qmsi_set_phase(struct device *dev, int access_op,
+			      uint32_t pwm, uint8_t phase)
+{
+	ARG_UNUSED(dev);
+	ARG_UNUSED(access_op);
+	ARG_UNUSED(pwm);
+	ARG_UNUSED(phase);
+
+	return -ENOTSUP;
+}
 
 static struct pwm_driver_api pwm_qmsi_drv_api_funcs = {
 	.config = pwm_qmsi_configure,
 	.set_values = pwm_qmsi_set_values,
 	.set_period = pwm_qmsi_set_period,
 	.set_duty_cycle = pwm_qmsi_set_duty_cycle,
+	.set_phase = pwm_qmsi_set_phase
 };
 
 static int pwm_qmsi_init(struct device *dev)

include/pwm.h

@@ -114,8 +114,10 @@ static inline int pwm_pin_configure(struct device *dev, uint8_t pwm,
  *
  * @param dev Pointer to the device structure for the driver instance.
  * @param pwm PWM output.
- * @param on ON value set to the PWM.
- * @param off OFF value set to the PWM.
+ * @param on ON value (number of timer count) set to the PWM. HW specific.
+ *	     How far from the beginning of a PWM cycle the PWM pulse starts.
+ * @param off OFF value (number of timer count) set to the PWM. HW specific.
+ *	      How far from the beginning of a PWM cycle the PWM pulse stops.
  *
  * @retval 0 If successful.
  * @retval Negative errno code if failure.
@@ -220,8 +222,10 @@ static inline int pwm_all_configure(struct device *dev, int flags)
  * @brief Set the ON/OFF values for all PWM outputs.
  *
  * @param dev Pointer to the device structure for the driver instance.
- * @param on ON value set to the PWM.
- * @param off OFF value set to the PWM.
+ * @param on ON value (number of timer count) set to the PWM. HW specific.
+ *	     How far from the beginning of a PWM cycle the PWM pulse starts.
+ * @param off OFF value (number of timer count) set to the PWM. HW specific.
+ *	      How far from the beginning of a PWM cycle the PWM pulse stops.
  *
  * @retval 0 If successful.
  * @retval Negative errno code if failure.