> -----Original Message----- > From: Kim, Milo [mailto:milo....@ti.com] > Sent: Thursday, November 29, 2012 2:18 PM > To: Andrew Morton > Cc: Samuel Ortiz; a.zu...@towertech.it; swar...@wwwdotorg.org; Venu > Byravarasu; Sivaram Nair; linux-kernel@vger.kernel.org > Subject: [PATCH 2/2] rtc-tps65910: enable RTC power domain on initialization > > Enabling RTC HW block depends on the default value of TPS65910 register. > In some mode, RTC block is disabled by default.(eg. AM3517 Craneboard) > In this case, RTC_PWDN(RTC power down) bit should be cleared to enable > the RTC HW block.
>From the description of RTC_PWDN bit of DEVCTRL_REG in TPS65910 data sheet it is very evident that the default value of RTC_PWDN is 0. Probably on "AM3517 Craneboard", some code is running prior to the RTC driver which might be writing 1 on to this bit. IMO you must disable that write operation instead of just writing default value into a register. > > This patch also works in case that RTC block is active by default, > because there is no side effect even if the bit is updated again. > > Tested on AM3517 Craneboard. > > Signed-off-by: Milo(Woogyom) Kim <milo....@ti.com> > --- > drivers/rtc/rtc-tps65910.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/rtc/rtc-tps65910.c b/drivers/rtc/rtc-tps65910.c > index e8d44bc..b4d9f02 100644 > --- a/drivers/rtc/rtc-tps65910.c > +++ b/drivers/rtc/rtc-tps65910.c > @@ -247,6 +247,13 @@ static int __devinit tps65910_rtc_probe(struct > platform_device *pdev) > return ret; > > dev_dbg(&pdev->dev, "Enabling rtc-tps65910.\n"); > + > + /* Enable RTC digital power domain */ > + ret = regmap_update_bits(tps65910->regmap, TPS65910_DEVCTRL, > + DEVCTRL_RTC_PWDN_MASK, 0 << > DEVCTRL_RTC_PWDN_SHIFT); > + if (ret < 0) > + return ret; > + > rtc_reg = TPS65910_RTC_CTRL_STOP_RTC; > ret = regmap_write(tps65910->regmap, TPS65910_RTC_CTRL, > rtc_reg); > if (ret < 0) > -- > 1.7.9.5 > > > Best Regards, > Milo > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
