video: backlight: lp855x: Get PWM for PWM mode during probe

Also deprecate the pwm-period DT property, as it is now redundant
(pwms property already contains period value).

Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230519180728.2281-3-aweber.kernel@gmail.com

Author: refractionware

drivers/video/backlight/lp855x_bl.c

@@ -218,23 +218,10 @@ static int lp855x_configure(struct lp855x *lp)
 
 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 {
-	struct pwm_device *pwm;
 	struct pwm_state state;
 
-	/* request pwm device with the consumer name */
-	if (!lp->pwm) {
-		pwm = devm_pwm_get(lp->dev, lp->chipname);
-		if (IS_ERR(pwm))
-			return;
-
-		lp->pwm = pwm;
-
-		pwm_init_state(lp->pwm, &state);
-	} else {
-		pwm_get_state(lp->pwm, &state);
-	}
+	pwm_get_state(lp->pwm, &state);
 
-	state.period = lp->pdata->period_ns;
 	state.duty_cycle = div_u64(br * state.period, max_br);
 	state.enabled = state.duty_cycle;
 
@@ -339,6 +326,7 @@ static int lp855x_parse_dt(struct lp855x *lp)
 	of_property_read_string(node, "bl-name", &pdata->name);
 	of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
 	of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
+	/* Deprecated, specify period in pwms property instead */
 	of_property_read_u32(node, "pwm-period", &pdata->period_ns);
 
 	/* Fill ROM platform data if defined */
@@ -399,6 +387,7 @@ static int lp855x_probe(struct i2c_client *cl)
 	const struct i2c_device_id *id = i2c_client_get_device_id(cl);
 	const struct acpi_device_id *acpi_id = NULL;
 	struct device *dev = &cl->dev;
+	struct pwm_state pwmstate;
 	struct lp855x *lp;
 	int ret;
 
@@ -457,11 +446,6 @@ static int lp855x_probe(struct i2c_client *cl)
 		}
 	}
 
-	if (lp->pdata->period_ns > 0)
-		lp->mode = PWM_BASED;
-	else
-		lp->mode = REGISTER_BASED;
-
 	lp->supply = devm_regulator_get(dev, "power");
 	if (IS_ERR(lp->supply)) {
 		if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
@@ -472,11 +456,31 @@ static int lp855x_probe(struct i2c_client *cl)
 	lp->enable = devm_regulator_get_optional(dev, "enable");
 	if (IS_ERR(lp->enable)) {
 		ret = PTR_ERR(lp->enable);
-		if (ret == -ENODEV) {
+		if (ret == -ENODEV)
 			lp->enable = NULL;
-		} else {
+		else
 			return dev_err_probe(dev, ret, "getting enable regulator\n");
-		}
+	}
+
+	lp->pwm = devm_pwm_get(lp->dev, lp->chipname);
+	if (IS_ERR(lp->pwm)) {
+		ret = PTR_ERR(lp->pwm);
+		if (ret == -ENODEV || ret == -EINVAL)
+			lp->pwm = NULL;
+		else
+			return dev_err_probe(dev, ret, "getting PWM\n");
+
+		lp->mode = REGISTER_BASED;
+		dev_dbg(dev, "mode: register based\n");
+	} else {
+		pwm_init_state(lp->pwm, &pwmstate);
+		/* Legacy platform data compatibility */
+		if (lp->pdata->period_ns > 0)
+			pwmstate.period = lp->pdata->period_ns;
+		pwm_apply_state(lp->pwm, &pwmstate);
+
+		lp->mode = PWM_BASED;
+		dev_dbg(dev, "mode: PWM based\n");
 	}
 
 	if (lp->supply) {