rtc: stmp3xxx: add wdt-accessor function
This RTC also includes a watchdog timer. Provide an accessor function
for setting the watchdog timeout value which will be picked up by a
watchdog driver. Also register the platform_device for the watchdog here
to get the boot-time dependencies right.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index b2a8ed9..98f0d3c 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -27,6 +27,8 @@
#include <linux/slab.h>
#include <linux/of_device.h>
#include <linux/of.h>
+#include <linux/stmp_device.h>
+#include <linux/stmp3xxx_rtc_wdt.h>
#include <mach/common.h>
@@ -36,6 +38,7 @@
#define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001
#define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002
#define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004
+#define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010
#define STMP3XXX_RTC_STAT 0x10
#define STMP3XXX_RTC_STAT_STALE_SHIFT 16
@@ -45,6 +48,8 @@
#define STMP3XXX_RTC_ALARM 0x40
+#define STMP3XXX_RTC_WATCHDOG 0x50
+
#define STMP3XXX_RTC_PERSISTENT0 0x60
#define STMP3XXX_RTC_PERSISTENT0_SET 0x64
#define STMP3XXX_RTC_PERSISTENT0_CLR 0x68
@@ -52,12 +57,70 @@
#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN 0x00000004
#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE 0x00000080
+#define STMP3XXX_RTC_PERSISTENT1 0x70
+/* missing bitmask in headers */
+#define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000
+
struct stmp3xxx_rtc_data {
struct rtc_device *rtc;
void __iomem *io;
int irq_alarm;
};
+#if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
+/**
+ * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
+ * @dev: the parent device of the watchdog (= the RTC)
+ * @timeout: the desired value for the timeout register of the watchdog.
+ * 0 disables the watchdog
+ *
+ * The watchdog needs one register and two bits which are in the RTC domain.
+ * To handle the resource conflict, the RTC driver will create another
+ * platform_device for the watchdog driver as a child of the RTC device.
+ * The watchdog driver is passed the below accessor function via platform_data
+ * to configure the watchdog. Locking is not needed because accessing SET/CLR
+ * registers is atomic.
+ */
+
+static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
+{
+ struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+
+ if (timeout) {
+ writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
+ writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
+ rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
+ writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
+ rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET);
+ } else {
+ writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
+ rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
+ writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
+ rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR);
+ }
+}
+
+static struct stmp3xxx_wdt_pdata wdt_pdata = {
+ .wdt_set_timeout = stmp3xxx_wdt_set_timeout,
+};
+
+static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
+{
+ struct platform_device *wdt_pdev =
+ platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
+
+ if (wdt_pdev) {
+ wdt_pdev->dev.parent = &rtc_pdev->dev;
+ wdt_pdev->dev.platform_data = &wdt_pdata;
+ platform_device_add(wdt_pdev);
+ }
+}
+#else
+static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
+{
+}
+#endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
+
static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
{
/*
@@ -233,6 +296,7 @@
goto out_irq_alarm;
}
+ stmp3xxx_wdt_register(pdev);
return 0;
out_irq_alarm: