rtc: mt6397: improvements of rtc driver

- use regmap_read_poll_timeout to drop while-loop
- use devm-api to drop remove-callback

Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Josef Friedl <josef.friedl@speed.at>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/rtc/rtc-mt6397.c

@@ -4,36 +4,33 @@
 * Author: Tianping.Fang <tianping.fang@mediatek.com>
 */
 
-#include <linux/delay.h>
-#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/mt6397/core.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/rtc.h>
 #include <linux/mfd/mt6397/rtc.h>
+#include <linux/mod_devicetable.h>
 
 static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
 {
-	unsigned long timeout = jiffies + HZ;
 	int ret;
 	u32 data;
 
 	ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_WRTGR, 1);
 	if (ret < 0)
 		return ret;
 
-	while (1) {
-		ret = regmap_read(rtc->regmap, rtc->addr_base + RTC_BBPU,
-				  &data);
-		if (ret < 0)
-			break;
-		if (!(data & RTC_BBPU_CBUSY))
-			break;
-		if (time_after(jiffies, timeout)) {
-			ret = -ETIMEDOUT;
-			break;
-		}
-		cpu_relax();
-	}
+	ret = regmap_read_poll_timeout(rtc->regmap,
+					rtc->addr_base + RTC_BBPU, data,
+					!(data & RTC_BBPU_CBUSY),
+					MTK_RTC_POLL_DELAY_US,
+					MTK_RTC_POLL_TIMEOUT);
+	if (ret < 0)
+		dev_err(rtc->dev, "failed to write WRTGE: %d\n", ret);
 
 	return ret;
 }
@@ -266,19 +263,19 @@ static int mtk_rtc_probe(struct platform_device *pdev)
 		return rtc->irq;
 
 	rtc->regmap = mt6397_chip->regmap;
-	rtc->dev = &pdev->dev;
 	mutex_init(&rtc->lock);
 
 	platform_set_drvdata(pdev, rtc);
 
-	rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev);
+	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(rtc->rtc_dev))
 		return PTR_ERR(rtc->rtc_dev);
 
-	ret = request_threaded_irq(rtc->irq, NULL,
-				   mtk_rtc_irq_handler_thread,
-				   IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
-				   "mt6397-rtc", rtc);
+	ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL,
+					mtk_rtc_irq_handler_thread,
+					IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
+					"mt6397-rtc", rtc);
+
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
 			rtc->irq, ret);
@@ -300,15 +297,6 @@ static int mtk_rtc_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int mtk_rtc_remove(struct platform_device *pdev)
-{
-	struct mt6397_rtc *rtc = platform_get_drvdata(pdev);
-
-	free_irq(rtc->irq, rtc);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM_SLEEP
 static int mt6397_rtc_suspend(struct device *dev)
 {
@@ -347,7 +335,6 @@ static struct platform_driver mtk_rtc_driver = {
 		.pm = &mt6397_pm_ops,
 	},
 	.probe	= mtk_rtc_probe,
-	.remove = mtk_rtc_remove,
 };
 
 module_platform_driver(mtk_rtc_driver);