Hi, On 01/04/2015 at 11:24:56 +0530, Lokesh Vutla wrote : > RTC module contains a kicker mechanism to prevent any spurious writes > from changing the register values. This mechanism requires two MMR > writes to the KICK0 and KICK1 registers with exact data values > before the kicker lock mechanism is released. > > Currently the driver release the lock in the probe and leaves it enabled > until the rtc driver removal. This eliminates the idea of preventing > spurious writes when RTC driver is loaded. > So implement rtc lock and unlock functions before and after register writes. > > Signed-off-by: Lokesh Vutla <lokeshvutla@xxxxxx> > --- > - This is as advised by Paul to implement lock and unlock functions in > the driver and not to unlock and leave it in probe. > The same discussion can be seen here: > http://www.mail-archive.com/linux-omap%40vger.kernel.org/msg111588.html > > drivers/rtc/rtc-omap.c | 46 ++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 38 insertions(+), 8 deletions(-) > > diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c > index 8e5851a..96cc613 100644 > --- a/drivers/rtc/rtc-omap.c > +++ b/drivers/rtc/rtc-omap.c > @@ -156,6 +156,22 @@ static inline void rtc_writel(struct omap_rtc *rtc, unsigned int reg, u32 val) > writel(val, rtc->base + reg); > } > > +static void rtc_unlock(struct omap_rtc *rtc) > +{ > + if (rtc->type->has_kicker) { Instead of testing for has_kicker each time, I would add .lock and .unlock to omap_rtc_device_type and directly use rtc->type->lock and rtc->type->unlock. > + rtc_writel(rtc, OMAP_RTC_KICK0_REG, KICK0_VALUE); > + rtc_writel(rtc, OMAP_RTC_KICK1_REG, KICK1_VALUE); > + } > +} > + -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
