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path: root/drivers/rtc/rtc-stmp3xxx.c
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Diffstat (limited to 'drivers/rtc/rtc-stmp3xxx.c')
-rw-r--r--drivers/rtc/rtc-stmp3xxx.c66
1 files changed, 60 insertions, 6 deletions
diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 2939cdcb2688..eb09eddf39b8 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -42,6 +42,8 @@
#define STMP3XXX_RTC_STAT 0x10
#define STMP3XXX_RTC_STAT_STALE_SHIFT 16
#define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000
+#define STMP3XXX_RTC_STAT_XTAL32000_PRESENT 0x10000000
+#define STMP3XXX_RTC_STAT_XTAL32768_PRESENT 0x08000000
#define STMP3XXX_RTC_SECONDS 0x30
@@ -52,9 +54,13 @@
#define STMP3XXX_RTC_PERSISTENT0 0x60
#define STMP3XXX_RTC_PERSISTENT0_SET 0x64
#define STMP3XXX_RTC_PERSISTENT0_CLR 0x68
-#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN 0x00000002
-#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN 0x00000004
-#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE 0x00000080
+#define STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE (1 << 0)
+#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN (1 << 1)
+#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN (1 << 2)
+#define STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP (1 << 4)
+#define STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP (1 << 5)
+#define STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ (1 << 6)
+#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE (1 << 7)
#define STMP3XXX_RTC_PERSISTENT1 0x70
/* missing bitmask in headers */
@@ -248,6 +254,9 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
{
struct stmp3xxx_rtc_data *rtc_data;
struct resource *r;
+ u32 rtc_stat;
+ u32 pers0_set, pers0_clr;
+ u32 crystalfreq = 0;
int err;
rtc_data = devm_kzalloc(&pdev->dev, sizeof(*rtc_data), GFP_KERNEL);
@@ -268,8 +277,8 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
rtc_data->irq_alarm = platform_get_irq(pdev, 0);
- if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
- STMP3XXX_RTC_STAT_RTC_PRESENT)) {
+ rtc_stat = readl(rtc_data->io + STMP3XXX_RTC_STAT);
+ if (!(rtc_stat & STMP3XXX_RTC_STAT_RTC_PRESENT)) {
dev_err(&pdev->dev, "no device onboard\n");
return -ENODEV;
}
@@ -282,9 +291,54 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev)
return err;
}
+ /*
+ * Obviously the rtc needs a clock input to be able to run.
+ * This clock can be provided by an external 32k crystal. If that one is
+ * missing XTAL must not be disabled in suspend which consumes a
+ * lot of power. Normally the presence and exact frequency (supported
+ * are 32000 Hz and 32768 Hz) is detectable from fuses, but as reality
+ * proves these fuses are not blown correctly on all machines, so the
+ * frequency can be overridden in the device tree.
+ */
+ if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32000_PRESENT)
+ crystalfreq = 32000;
+ else if (rtc_stat & STMP3XXX_RTC_STAT_XTAL32768_PRESENT)
+ crystalfreq = 32768;
+
+ of_property_read_u32(pdev->dev.of_node, "stmp,crystal-freq",
+ &crystalfreq);
+
+ switch (crystalfreq) {
+ case 32000:
+ /* keep 32kHz crystal running in low-power mode */
+ pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ |
+ STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
+ STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
+ pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
+ break;
+ case 32768:
+ /* keep 32.768kHz crystal running in low-power mode */
+ pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
+ STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
+ pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP |
+ STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ;
+ break;
+ default:
+ dev_warn(&pdev->dev,
+ "invalid crystal-freq specified in device-tree. Assuming no crystal\n");
+ /* fall-through */
+ case 0:
+ /* keep XTAL on in low-power mode */
+ pers0_set = STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP;
+ pers0_clr = STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP |
+ STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE;
+ }
+
+ writel(pers0_set, rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
+
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
- STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
+ STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE | pers0_clr,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |