diff options
Diffstat (limited to 'drivers/rtc/rtc-stmp3xxx.c')
| -rw-r--r-- | drivers/rtc/rtc-stmp3xxx.c | 66 |
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 | |