Patchwork [v2,2/4] rtc: OMAP: Add system pm_power_off to rtc driver

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Submitter AnilKumar Chimata
Date Nov. 16, 2012, 12:08 p.m.
Message ID <1353067706-29491-3-git-send-email-anilkumar@ti.com>
Download mbox | patch
Permalink /patch/199558/
State New
Headers show

Comments

AnilKumar Chimata - Nov. 16, 2012, 12:08 p.m.
From: Colin Foe-Parker <colin.foeparker@logicpd.com>

Add system power off control to rtc driver which is the in-charge
of controlling the BeagleBone system power. The power_off routine
can be hooked up to "pm_power_off" system call.

System power off sequence:-
* Set PMIC STATUS_OFF when PMIC_POWER_EN is pulled low
* Enable PMIC_POWER_EN in rtc module
* Set rtc ALARM2 time
* Enable ALARM2 interrupt

Added while (1); after the above steps to make sure that no other
process acquire cpu. Otherwise we might see an unexpected behaviour
because we are shutting down all the power rails of SoC except RTC.

Signed-off-by: Colin Foe-Parker <colin.foeparker@logicpd.com>
[anilkumar@ti.com: move poweroff additions to rtc driver]
Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
---
 Documentation/devicetree/bindings/rtc/rtc-omap.txt |    5 ++
 drivers/rtc/rtc-omap.c                             |   81 +++++++++++++++++++-
 2 files changed, 85 insertions(+), 1 deletion(-)

Patch

diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
index b47aa41..8d9f4f9 100644
--- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
+++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
@@ -6,6 +6,10 @@  Required properties:
 - interrupts: rtc timer, alarm interrupts in order
 - interrupt-parent: phandle for the interrupt controller
 
+Optional properties:
+- ti,system-power-controller: Telling whether or not rtc is controlling
+  the system power.
+
 Example:
 
 rtc@1c23000 {
@@ -14,4 +18,5 @@  rtc@1c23000 {
 	interrupts = <19
 		      19>;
 	interrupt-parent = <&intc>;
+	ti,system-power-controller;
 };
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 6009714..c31f93a 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -72,6 +72,14 @@ 
 #define OMAP_RTC_KICK0_REG		0x6c
 #define OMAP_RTC_KICK1_REG		0x70
 
+#define OMAP_RTC_ALARM2_SECONDS_REG	0x80
+#define OMAP_RTC_ALARM2_MINUTES_REG	0x84
+#define OMAP_RTC_ALARM2_HOURS_REG	0x88
+#define OMAP_RTC_ALARM2_DAYS_REG	0x8c
+#define OMAP_RTC_ALARM2_MONTHS_REG	0x90
+#define OMAP_RTC_ALARM2_YEARS_REG	0x94
+#define OMAP_RTC_PMIC_REG		0x98
+
 /* OMAP_RTC_CTRL_REG bit fields: */
 #define OMAP_RTC_CTRL_SPLIT		(1<<7)
 #define OMAP_RTC_CTRL_DISABLE		(1<<6)
@@ -93,15 +101,21 @@ 
 #define OMAP_RTC_STATUS_BUSY            (1<<0)
 
 /* OMAP_RTC_INTERRUPTS_REG bit fields: */
+#define OMAP_RTC_INTERRUPTS_IT_ALARM2   (1<<4)
 #define OMAP_RTC_INTERRUPTS_IT_ALARM    (1<<3)
 #define OMAP_RTC_INTERRUPTS_IT_TIMER    (1<<2)
 
+/* OMAP_RTC_PMIC_REG bit fields: */
+#define OMAP_RTC_PMIC_POWER_EN_EN       (1<<16)
+
 /* OMAP_RTC_KICKER values */
 #define	KICK0_VALUE			0x83e70b13
 #define	KICK1_VALUE			0x95a4f1e0
 
 #define	OMAP_RTC_HAS_KICKER		0x1
 
+#define SHUTDOWN_TIME_SEC		2
+
 static void __iomem	*rtc_base;
 
 #define rtc_read(addr)		readb(rtc_base + (addr))
@@ -290,6 +304,63 @@  static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
 	return 0;
 }
 
+/*
+ * rtc_power_off: Set the pmic power off sequence. The RTC generates
+ * pmic_pwr_enable control, which can be used to control an external
+ * PMIC.
+ */
+static void rtc_power_off(void)
+{
+	u32 val;
+	struct rtc_time tm;
+	spinlock_t lock;
+	unsigned long flags, time;
+
+	spin_lock_init(&lock);
+
+	/* Set PMIC power enable */
+	val = readl(rtc_base + OMAP_RTC_PMIC_REG);
+	writel(val | OMAP_RTC_PMIC_POWER_EN_EN, rtc_base + OMAP_RTC_PMIC_REG);
+
+	/* Read rtc time */
+	omap_rtc_read_time(NULL, &tm);
+
+	/* Convert Gregorian date to seconds since 01-01-1970 00:00:00 */
+	rtc_tm_to_time(&tm, &time);
+
+	/* Add shutdown time to the current value */
+	time += SHUTDOWN_TIME_SEC;
+
+	/* Convert seconds since 01-01-1970 00:00:00 to Gregorian date */
+	rtc_time_to_tm(time, &tm);
+
+	if (tm2bcd(&tm) < 0)
+		return;
+
+	pr_info("System will go to power_off state in approx. %d secs\n",
+			SHUTDOWN_TIME_SEC);
+
+	/*
+	 * pmic_pwr_enable is controlled by means of ALARM2 event. So here
+	 * programming alarm2 expiry time and enabling alarm2 interrupt
+	 */
+	rtc_write(tm.tm_sec, OMAP_RTC_ALARM2_SECONDS_REG);
+	rtc_write(tm.tm_min, OMAP_RTC_ALARM2_MINUTES_REG);
+	rtc_write(tm.tm_hour, OMAP_RTC_ALARM2_HOURS_REG);
+	rtc_write(tm.tm_mday, OMAP_RTC_ALARM2_DAYS_REG);
+	rtc_write(tm.tm_mon, OMAP_RTC_ALARM2_MONTHS_REG);
+	rtc_write(tm.tm_year, OMAP_RTC_ALARM2_YEARS_REG);
+
+	/* Enable alarm2 interrupt */
+	val = readl(rtc_base + OMAP_RTC_INTERRUPTS_REG);
+	writel(val | OMAP_RTC_INTERRUPTS_IT_ALARM2,
+				rtc_base + OMAP_RTC_INTERRUPTS_REG);
+
+	/* Do not allow to execute any other task */
+	spin_lock_irqsave(&lock, flags);
+	while (1);
+}
+
 static struct rtc_class_ops omap_rtc_ops = {
 	.read_time	= omap_rtc_read_time,
 	.set_time	= omap_rtc_set_time,
@@ -327,12 +398,16 @@  static int __init omap_rtc_probe(struct platform_device *pdev)
 	struct resource		*res, *mem;
 	struct rtc_device	*rtc;
 	u8			reg, new_ctrl;
+	bool			pm_off = false;
 	const struct platform_device_id *id_entry;
 	const struct of_device_id *of_id;
 
 	of_id = of_match_device(omap_rtc_of_match, &pdev->dev);
-	if (of_id)
+	if (of_id) {
 		pdev->id_entry = of_id->data;
+		pm_off = of_property_read_bool(pdev->dev.of_node,
+					"ti,system-power-controller");
+	}
 
 	omap_rtc_timer = platform_get_irq(pdev, 0);
 	if (omap_rtc_timer <= 0) {
@@ -385,6 +460,10 @@  static int __init omap_rtc_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, rtc);
 	dev_set_drvdata(&rtc->dev, mem);
 
+	/* RTC power off */
+	if (pm_off && !pm_power_off)
+		pm_power_off = rtc_power_off;
+
 	/* clear pending irqs, and set 1/second periodic,
 	 * which we'll use instead of update irqs
 	 */