pwm: dwc: Prepare removing pwm_chip from driver data

This prepares the driver for further changes that will drop struct
pwm_chip chip from struct dwc_pwm. Use the pwm_chip as driver
data and return value of dwc_pwm_alloc() instead of the dwc_pwm to get
access to the pwm_chip in dwc_pwm_probe() and dwc_pwm_suspend() without
using dwc->chip.

Thanks to Raag Jadav for providing a hunk of this patch that Uwe missed
during creation of this patch.

Link: https://lore.kernel.org/r/008ce5ab84b8e3baa3e81ab6d36dbb0e4be5c319.1707900770.git.u.kleine-koenig@pengutronix.de
Link: https://lore.kernel.org/r/20240219033835.11369-2-raag.jadav@intel.comSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-dwc-core.c

@@ -159,21 +159,23 @@ static const struct pwm_ops dwc_pwm_ops = {
 	.get_state = dwc_pwm_get_state,
 };
 
-struct dwc_pwm *dwc_pwm_alloc(struct device *dev)
+struct pwm_chip *dwc_pwm_alloc(struct device *dev)
 {
+	struct pwm_chip *chip;
 	struct dwc_pwm *dwc;
 
 	dwc = devm_kzalloc(dev, sizeof(*dwc), GFP_KERNEL);
 	if (!dwc)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
+	chip = &dwc->chip;
 
 	dwc->clk_ns = 10;
-	dwc->chip.dev = dev;
-	dwc->chip.ops = &dwc_pwm_ops;
-	dwc->chip.npwm = DWC_TIMERS_TOTAL;
+	chip->dev = dev;
+	chip->ops = &dwc_pwm_ops;
+	chip->npwm = DWC_TIMERS_TOTAL;
 
-	dev_set_drvdata(dev, dwc);
-	return dwc;
+	dev_set_drvdata(dev, chip);
+	return chip;
 }
 EXPORT_SYMBOL_GPL(dwc_pwm_alloc);
 

drivers/pwm/pwm-dwc.c

@@ -28,12 +28,14 @@
 static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
 {
 	struct device *dev = &pci->dev;
+	struct pwm_chip *chip;
 	struct dwc_pwm *dwc;
 	int ret;
 
-	dwc = dwc_pwm_alloc(dev);
-	if (!dwc)
-		return -ENOMEM;
+	chip = dwc_pwm_alloc(dev);
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	dwc = to_dwc_pwm(chip);
 
 	ret = pcim_enable_device(pci);
 	if (ret) {
@@ -55,7 +57,7 @@ static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
 		return -ENOMEM;
 	}
 
-	ret = devm_pwmchip_add(dev, &dwc->chip);
+	ret = devm_pwmchip_add(dev, chip);
 	if (ret)
 		return ret;
 
@@ -73,13 +75,14 @@ static void dwc_pwm_remove(struct pci_dev *pci)
 
 static int dwc_pwm_suspend(struct device *dev)
 {
-	struct dwc_pwm *dwc = dev_get_drvdata(dev);
+	struct pwm_chip *chip = dev_get_drvdata(dev);
+	struct dwc_pwm *dwc = to_dwc_pwm(chip);
 	int i;
 
 	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
-		if (dwc->chip.pwms[i].state.enabled) {
+		if (chip->pwms[i].state.enabled) {
 			dev_err(dev, "PWM %u in use by consumer (%s)\n",
-				i, dwc->chip.pwms[i].label);
+				i, chip->pwms[i].label);
 			return -EBUSY;
 		}
 		dwc->ctx[i].cnt = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(i));
@@ -92,7 +95,8 @@ static int dwc_pwm_suspend(struct device *dev)
 
 static int dwc_pwm_resume(struct device *dev)
 {
-	struct dwc_pwm *dwc = dev_get_drvdata(dev);
+	struct pwm_chip *chip = dev_get_drvdata(dev);
+	struct dwc_pwm *dwc = to_dwc_pwm(chip);
 	int i;
 
 	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {

drivers/pwm/pwm-dwc.h

@@ -57,4 +57,4 @@ static inline void dwc_pwm_writel(struct dwc_pwm *dwc, u32 value, u32 offset)
 	writel(value, dwc->base + offset);
 }
 
-extern struct dwc_pwm *dwc_pwm_alloc(struct device *dev);
+extern struct pwm_chip *dwc_pwm_alloc(struct device *dev);