From mboxrd@z Thu Jan 1 00:00:00 1970 From: keerthy Subject: Re: [PATCH 0/5] AM437x: Add rtc-only + DDR mode support Date: Mon, 25 Mar 2019 07:13:53 +0530 Message-ID: <1fadeed8-b091-43c8-e7ec-f29ad0fff82c@ti.com> References: <20190322171619.4180-1-j-keerthy@ti.com> <20190322183253.w2uuhglttwmmxfnx@shell.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190322183253.w2uuhglttwmmxfnx@shell.armlinux.org.uk> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Russell King - ARM Linux admin Cc: linux-rtc@vger.kernel.org, a.zummo@towertech.it, alexandre.belloni@bootlin.com, d-gerlach@ti.com, tony@atomide.com, t-kristo@ti.com, ssantosh@kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: linux-omap@vger.kernel.org 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. >> 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. > >> 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 >> >