1 files changed, 48 insertions, 2 deletions

diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
index 5e14651b71a8..7ad2d7965b4e 100644
--- a/drivers/rtc/rtc-jz4740.c
+++ b/drivers/rtc/rtc-jz4740.c
@@ -29,6 +29,10 @@
 #define JZ_REG_RTC_HIBERNATE	0x20
 #define JZ_REG_RTC_SCRATCHPAD	0x34
 
+/* The following are present on the jz4780 */
+#define JZ_REG_RTC_WENR	0x3C
+#define JZ_RTC_WENR_WEN	BIT(31)
+
 #define JZ_RTC_CTRL_WRDY	BIT(7)
 #define JZ_RTC_CTRL_1HZ		BIT(6)
 #define JZ_RTC_CTRL_1HZ_IRQ	BIT(5)
@@ -37,8 +41,17 @@
 #define JZ_RTC_CTRL_AE		BIT(2)
 #define JZ_RTC_CTRL_ENABLE	BIT(0)
 
+/* Magic value to enable writes on jz4780 */
+#define JZ_RTC_WENR_MAGIC	0xA55A
+
+enum jz4740_rtc_type {
+	ID_JZ4740,
+	ID_JZ4780,
+};
+
 struct jz4740_rtc {
 	void __iomem *base;
+	enum jz4740_rtc_type type;
 
 	struct rtc_device *rtc;
 
@@ -64,11 +77,33 @@ static int jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
 	return timeout ? 0 : -EIO;
 }
 
+static inline int jz4780_rtc_enable_write(struct jz4740_rtc *rtc)
+{
+	uint32_t ctrl;
+	int ret, timeout = 1000;
+
+	ret = jz4740_rtc_wait_write_ready(rtc);
+	if (ret != 0)
+		return ret;
+
+	writel(JZ_RTC_WENR_MAGIC, rtc->base + JZ_REG_RTC_WENR);
+
+	do {
+		ctrl = readl(rtc->base + JZ_REG_RTC_WENR);
+	} while (!(ctrl & JZ_RTC_WENR_WEN) && --timeout);
+
+	return timeout ? 0 : -EIO;
+}
+
 static inline int jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
 	uint32_t val)
 {
-	int ret;
-	ret = jz4740_rtc_wait_write_ready(rtc);
+	int ret = 0;
+
+	if (rtc->type >= ID_JZ4780)
+		ret = jz4780_rtc_enable_write(rtc);
+	if (ret == 0)
+		ret = jz4740_rtc_wait_write_ready(rtc);
 	if (ret == 0)
 		writel(val, rtc->base + reg);
 
@@ -216,11 +251,14 @@ static int jz4740_rtc_probe(struct platform_device *pdev)
 	struct jz4740_rtc *rtc;
 	uint32_t scratchpad;
 	struct resource *mem;
+	const struct platform_device_id *id = platform_get_device_id(pdev);
 
 	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
 	if (!rtc)
 		return -ENOMEM;
 
+	rtc->type = id->driver_data;
+
 	rtc->irq = platform_get_irq(pdev, 0);
 	if (rtc->irq < 0) {
 		dev_err(&pdev->dev, "Failed to get platform irq\n");
@@ -295,12 +333,20 @@ static const struct dev_pm_ops jz4740_pm_ops = {
 #define JZ4740_RTC_PM_OPS NULL
 #endif  /* CONFIG_PM */
 
+static const struct platform_device_id jz4740_rtc_ids[] = {
+	{ "jz4740-rtc", ID_JZ4740 },
+	{ "jz4780-rtc", ID_JZ4780 },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, jz4740_rtc_ids);
+
 static struct platform_driver jz4740_rtc_driver = {
 	.probe	 = jz4740_rtc_probe,
 	.driver	 = {
 		.name  = "jz4740-rtc",
 		.pm    = JZ4740_RTC_PM_OPS,
 	},
+	.id_table = jz4740_rtc_ids,
 };
 
 module_platform_driver(jz4740_rtc_driver);