On 03/04/2019 10:27:39+0530, Keerthy wrote: > Prepare rtc driver for rtc-only with DDR in self-refresh mode. > omap_rtc_power_off now should cater to two features: > > 1) RTC plus DDR in self-refresh is power a saving mode where in the > entire system including the different voltage rails from PMIC are > shutdown except the ones feeding on to RTC and DDR. DDR is kept in > self-refresh hence the contents are preserved. RTC ALARM2 is connected > to PMIC_EN line once we the ALARM2 is triggered we enter the mode with > DDR in self-refresh and RTC Ticking. After a predetermined time an RTC > ALARM1 triggers waking up the system[1]. The control goes to bootloader. > The bootloader then checks RTC scratchpad registers to confirm it was an > rtc_only wakeup and follows a different path, configure bare minimal > clocks for ddr and then jumps to the resume address in another RTC > scratchpad registers and transfers the control to Kernel. Kernel then > restores the saved context. omap_rtc_power_off_program does the ALARM2 > programming part. > > [1] http://www.ti.com/lit/ug/spruhl7h/spruhl7h.pdf Page 2884 > > 2) Power-off: This is usual poweroff mode. omap_rtc_power_off calls the > above omap_rtc_power_off_program function and in addition to that > programs the OMAP_RTC_PMIC_REG for any external wake ups for PMIC like > the pushbutton and shuts off the PMIC. > > Hence the split in omap_rtc_power_off. > > Signed-off-by: Keerthy <j-keerthy@xxxxxx> Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> > --- > > Changes in v3: > > * Exported out omap_rtc_power_off_program to rtc-omap header file > > drivers/rtc/rtc-omap.c | 49 ++++++++++++++++++++++++++++++------ > include/linux/rtc/rtc-omap.h | 7 ++++++ > 2 files changed, 48 insertions(+), 8 deletions(-) > create mode 100644 include/linux/rtc/rtc-omap.h > > diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c > index 32994b0dd139..a2941c875a06 100644 > --- a/drivers/rtc/rtc-omap.c > +++ b/drivers/rtc/rtc-omap.c > @@ -403,15 +403,12 @@ static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) > > static struct omap_rtc *omap_rtc_power_off_rtc; > > -/* > - * omap_rtc_poweroff: RTC-controlled power off > - * > - * The RTC can be used to control an external PMIC via the pmic_power_en pin, > - * which can be configured to transition to OFF on ALARM2 events. > - * > - * Called with local interrupts disabled. > +/** > + * omap_rtc_power_off_program: Set the pmic power off sequence. The RTC > + * generates pmic_pwr_enable control, which can be used to control an external > + * PMIC. > */ > -static void omap_rtc_power_off(void) > +int omap_rtc_power_off_program(struct device *dev) > { > struct omap_rtc *rtc = omap_rtc_power_off_rtc; > struct rtc_time tm; > @@ -425,6 +422,9 @@ static void omap_rtc_power_off(void) > rtc_writel(rtc, OMAP_RTC_PMIC_REG, val | OMAP_RTC_PMIC_POWER_EN_EN); > > again: > + /* Clear any existing ALARM2 event */ > + rtc_writel(rtc, OMAP_RTC_STATUS_REG, OMAP_RTC_STATUS_ALARM2); > + > /* set alarm one second from now */ > omap_rtc_read_time_raw(rtc, &tm); > seconds = tm.tm_sec; > @@ -461,6 +461,39 @@ static void omap_rtc_power_off(void) > > rtc->type->lock(rtc); > > + return 0; > +} > +EXPORT_SYMBOL(omap_rtc_power_off_program); > + > +/* > + * omap_rtc_poweroff: RTC-controlled power off > + * > + * The RTC can be used to control an external PMIC via the pmic_power_en pin, > + * which can be configured to transition to OFF on ALARM2 events. > + * > + * Notes: > + * The one-second alarm offset is the shortest offset possible as the alarm > + * registers must be set before the next timer update and the offset > + * calculation is too heavy for everything to be done within a single access > + * period (~15 us). > + * > + * Called with local interrupts disabled. > + */ > +static void omap_rtc_power_off(void) > +{ > + struct rtc_device *rtc = omap_rtc_power_off_rtc->rtc; > + u32 val; > + > + omap_rtc_power_off_program(rtc->dev.parent); > + > + /* Set PMIC power enable and EXT_WAKEUP in case PB power on is used */ > + omap_rtc_power_off_rtc->type->unlock(omap_rtc_power_off_rtc); > + val = rtc_readl(omap_rtc_power_off_rtc, OMAP_RTC_PMIC_REG); > + val |= OMAP_RTC_PMIC_POWER_EN_EN | OMAP_RTC_PMIC_EXT_WKUP_POL(0) | > + OMAP_RTC_PMIC_EXT_WKUP_EN(0); > + rtc_writel(omap_rtc_power_off_rtc, OMAP_RTC_PMIC_REG, val); > + omap_rtc_power_off_rtc->type->lock(omap_rtc_power_off_rtc); > + > /* > * Wait for alarm to trigger (within one second) and external PMIC to > * power off the system. Add a 500 ms margin for external latencies > diff --git a/include/linux/rtc/rtc-omap.h b/include/linux/rtc/rtc-omap.h > new file mode 100644 > index 000000000000..9f03a329e63f > --- /dev/null > +++ b/include/linux/rtc/rtc-omap.h > @@ -0,0 +1,7 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef _LINUX_RTCOMAP_H_ > +#define _LINUX_RTCOMAP_H_ > + > +int omap_rtc_power_off_program(struct device *dev); > +#endif /* _LINUX_RTCOMAP_H_ */ > -- > 2.17.1 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
