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Mon, 1 Apr 2019 22:42:43 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DLEE104.ent.ti.com (157.170.170.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5 via Frontend Transport; Mon, 1 Apr 2019 22:42:43 -0500 Received: from a0393675ula.india.ti.com (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id x323gb9F070613; Mon, 1 Apr 2019 22:42:41 -0500 From: Keerthy To: , , , Subject: [PATCH v2 1/5] rtc: OMAP: Add support for rtc-only mode Date: Tue, 2 Apr 2019 09:12:49 +0530 Message-ID: <20190402034253.4928-2-j-keerthy@ti.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190402034253.4928-1-j-keerthy@ti.com> References: <20190402034253.4928-1-j-keerthy@ti.com> MIME-Version: 1.0 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190401_204250_681924_EDAA7766 X-CRM114-Status: GOOD ( 17.38 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-rtc@vger.kernel.org, d-gerlach@ti.com, j-keerthy@ti.com, ssantosh@kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- drivers/rtc/rtc-omap.c | 48 +++++++++++++++++++++++++++++++++++------- 1 file changed, 40 insertions(+), 8 deletions(-) diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c index 32994b0dd139..b467154443a4 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) +static 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 +461,38 @@ static void omap_rtc_power_off(void) rtc->type->lock(rtc); + return 0; +} + +/* + * 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