Re: [PATCH 0/5] AM437x: Add rtc-only + DDR mode support

[Russell King - ARM Linux admin <linux@armlinux.org.uk>]

On Mon, Mar 25, 2019 at 07:13:53AM +0530, keerthy wrote:
> 
> 
> On 3/23/2019 12:02 AM, Russell King - ARM Linux admin wrote:
> > On Fri, Mar 22, 2019 at 10:46:14PM +0530, Keerthy wrote:
> > > RTC plus DDR in self-refresh is power a saving mode where in the entire
> >                                   "a power" ?
> 
> Will correct the above typo.
> 
> > 
> > > 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
> 
> As explained above All the voltage rails of PMIC are shut off except for RTC
> and DDR Rails.

You seem to be replying to yourself there - the quote above your reply
there is what you wrote.

> 
> > > 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
> > 
> > Doesn't make sense.
> > 
> > > and RTC Ticking. After a predetermined time an RTC ALARM1 triggers waking
> > > up the system.
> > 
> > Huh, you start off explaining the wiring above... how does RTC ALARM1
> > trigger waking up the system if RTC ALARM2 is connected to the PMIC
> > and all other power is shut down?
> The entire PMIC is shutdown but for RTC rail. RTC is a separate voltage
> domain and is powered up during this power save mode.
> 
> http://www.ti.com/lit/ug/spruhl7h/spruhl7h.pdf Page 2884.

I'm not asking for a reference, I'm asking for your cover letter to
make sense and actually be useful.  Right now, it's far from that.

Thanks.

> 
> > 
> > > 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.
> > > 
> > > The patch series adds rtc-only + DDR mode support am am437x
> > > Tested DS0, rtc+ddr back and forth on am437x-gp-evm board.
> > > 
> > > This mode works only with u-boot built with am43xx_evm_rtconly_defconfig
> > > 
> > > Additional patch is needed for omap-gpio save restore which will
> > > come as fixes later.
> > > 
> > > Keerthy (5):
> > >    rtc: OMAP: Add support for rtc-only mode
> > >    rtc: interface: Add power_off_program to rtc_class_ops
> > >    arm: mach-omap2: pm33xx: Add support for rtc+ddr in self refresh mode
> > >    soc: ti: pm33xx: Push the am33xx_push_sram_idle to the top
> > >    soc: ti: pm33xx: AM437X: Add rtc_only with ddr in self-refresh support
> > > 
> > >   arch/arm/mach-omap2/pm33xx-core.c    |  76 +++++++-
> > >   drivers/rtc/interface.c              |  12 ++
> > >   drivers/rtc/rtc-omap.c               |  49 ++++-
> > >   drivers/soc/ti/Kconfig               |   5 +-
> > >   drivers/soc/ti/pm33xx.c              | 272 ++++++++++++++++++++++-----
> > >   include/linux/platform_data/pm33xx.h |   5 +
> > >   include/linux/rtc.h                  |   2 +
> > >   7 files changed, 360 insertions(+), 61 deletions(-)
> > > 
> > > -- 
> > > 2.17.1
> > > 
> > > 
> > > _______________________________________________
> > > linux-arm-kernel mailing list
> > > linux-arm-kernel@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> > > 
> > 
> 

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