pm: Add power off control

From: Colin Foe-Parker <[email protected]>

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 <[email protected]>

[anilkumar at ti.com: move poweroff additions to rtc driver]

Signed-off-by AnilKumar Ch <[email protected]>

---
 Documentation/devicetree/bindings/rtc/rtc-omap.txt |    5 ++
 drivers/rtc/rtc-omap.c                             |   81 +++++++++++++++++++-
 2 files changed, 85 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/rtc/rtc-omap.txt +5 -0

index b47aa41..8d9f4f9 100644
@@ -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 at 1c23000 {

@@ -14,4 +18,5 @@ rtc at 1c23000 {
 	interrupts = <19
 		      19>;
 	interrupt-parent = <&intc>;
+	ti,system-power-controller;
 };

drivers/rtc/rtc-omap.c +80 -1

index 6009714..c31f93a 100644
@@ -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
 	 */

Signature · 1 line

1.7.9.5

+Andrew Morton

Quoted 15 lines · Chimata

From: Colin Foe-Parker <[email protected]>

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.

From: Colin Foe-Parker <[email protected]>

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 <[email protected]>

[anilkumar at ti.com: move poweroff additions to rtc driver]

Signed-off-by AnilKumar Ch <[email protected]>

...

drivers/rtc/rtc-omap.c +35 -0

+	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);

+}

...

drivers/rtc/rtc-omap.c static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) · line 361

Quoted 3 lines

drivers/rtc/rtc-omap.c +3 -0

+	/* Do not allow to execute any other task */
+	spin_lock_irqsave(&lock, flags);
+	while (1);

I suspect this doesn't do what you want it to do.

Firstly, please provide adequate code comments here so that code readers do not also need to be mind readers.

If you want to stop this CPU dead in its tracks (why?) then

	local_irq_disable();
	while (1)
		;		/* Note correct code layout */

will do it. But it means that the NMI watchdog (if present) will come along and whack the machine in the head a few seconds later. And this does nothing to stop other CPUs.

But not being a mind reader, I'm really at a loss to suggest what should be done here.

Quoted 15 lines · Andrew Morton

drivers/rtc/rtc-omap.c static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) · line 361

Quoted 3 lines

drivers/rtc/rtc-omap.c +3 -0

+	/* Do not allow to execute any other task */
+	spin_lock_irqsave(&lock, flags);
+	while (1);

I suspect this doesn't do what you want it to do.

Firstly, please provide adequate code comments here so that code readers do not also need to be mind readers.

If you want to stop this CPU dead in its tracks (why?) then

	local_irq_disable();
	while (1)
		;		/* Note correct code layout */

Quoted 6 lines

will do it. But it means that the NMI watchdog (if present) will come along and whack the machine in the head a few seconds later. And this does nothing to stop other CPUs.

But not being a mind reader, I'm really at a loss to suggest what should be done here.

It's hooking into the pm_power_off hook, which is called from kernel/sys.c via arch code. We will have already stopped all other CPUs at this point.

Why there's that while (1) there I don't know; when pm_power_off is not hooked, we don't do anything like that - and what will happen in that case is we'll return all the way back to sys_reboot(), which will call do_exit(0) on us.

I don't see a problem with that, and I don't see why we need to spin (without any power saving too) waiting for some event. If we've called sys_reboot with LINUX_REBOOT_CMD_POWER_OFF, we'd better have already killed most of userspace off by that time anyway.

From: Colin Foe-Parker <[email protected]>

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 <[email protected]>

[anilkumar at ti.com: move poweroff additions to rtc driver]

Signed-off-by AnilKumar Ch <[email protected]>

---
 Documentation/devicetree/bindings/rtc/rtc-omap.txt |    5 ++
 drivers/rtc/rtc-omap.c                             |   81 +++++++++++++++++++-
 2 files changed, 85 insertions(+), 1 deletion(-)

Documentation/devicetree/bindings/rtc/rtc-omap.txt +0 -0

index b47aa41..8d9f4f9 100644

Documentation/devicetree/bindings/rtc/rtc-omap.txt +1 -0

 Example:
 
 rtc at 1c23000 {

@@ -14,4 +18,5 @@ rtc at 1c23000 {
 	interrupts = <19
 		      19>;
 	interrupt-parent = <&intc>;
+	ti,system-power-controller;
 };

drivers/rtc/rtc-omap.c +80 -1

index 6009714..c31f93a 100644
@@ -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
 	 */

Signature · 1 line

1.7.9.5

From: Colin Foe-Parker <[email protected]>

Set tps65217 PMIC status to OFF if power enable toggle is supported. By setting this bit to 1 to enter PMIC to OFF state when PWR_EN pin is pulled low. Also adds a DT flag to specify that device pmic supports shutdown control or not.

Signed-off-by Colin Foe-Parker <[email protected]>

[anilkumar at ti.com: move the additions to tps65217 MFD driver]

Signed-off-by AnilKumar Ch <[email protected]>

---
 .../devicetree/bindings/regulator/tps65217.txt     |    4 ++++
 drivers/mfd/tps65217.c                             |   12 ++++++++++++
 2 files changed, 16 insertions(+)

Hi Anilkumar,

Quoted 7 lines · AnilKumar Ch

From: Colin Foe-Parker <[email protected]>

Set tps65217 PMIC status to OFF if power enable toggle is supported. By setting this bit to 1 to enter PMIC to OFF state when PWR_EN pin is pulled low. Also adds a DT flag to specify that device pmic supports shutdown control or not.

Quoted 7 lines

Signed-off-by Colin Foe-Parker <[email protected]>

[anilkumar at ti.com: move the additions to tps65217 MFD driver]

Signed-off-by AnilKumar Ch <[email protected]>

---
 .../devicetree/bindings/regulator/tps65217.txt     |    4 ++++
 drivers/mfd/tps65217.c                             |   12 ++++++++++++
 2 files changed, 16 insertions(+)

Applied, thanks.
I suppose you're not expecting the whole patchset to go through one tree ?

Set ti,pmic-shutdown-controller for BeagleBone in am335x-bone.dts file, this flag is used by the driver to set tps65217 PMIC status to OFF when PWR_EN toggle.

Signed-off-by AnilKumar Ch <[email protected]>

---
 arch/arm/boot/dts/am335x-bone.dts |    2 ++
 1 file changed, 2 insertions(+)

arch/arm/boot/dts/am335x-bone.dts +2 -0

index 2c33888..1d55190 100644
@@ -88,6 +88,8 @@
 /include/ "tps65217.dtsi"
 
 &tps {
+	ti,pmic-shutdown-controller;
+
 	regulators {
 		dcdc1_reg: regulator at 0 {
 			regulator-always-on;

Signature · 1 line

1.7.9.5

AM33XX family of devices uses RTC module, one has to manually enable this support to use RTC features. So this patch enable RTC driver in omap2plus_defconfig.

Signed-off-by AnilKumar Ch <[email protected]>

---
 arch/arm/configs/omap2plus_defconfig |    1 +
 1 file changed, 1 insertion(+)

arch/arm/configs/omap2plus_defconfig +0 -0

index a4b330e..8839ac9 100644

Quoted 14 lines · AnilKumar Ch

AM33XX family of devices uses RTC module, one has to manually enable this support to use RTC features. So this patch enable RTC driver in omap2plus_defconfig.

Signed-off-by AnilKumar Ch <[email protected]>

---
 arch/arm/configs/omap2plus_defconfig |    1 +
 1 file changed, 1 insertion(+)

arch/arm/configs/omap2plus_defconfig +0 -0

index a4b330e..8839ac9 100644

arch/arm/configs/omap2plus_defconfig CONFIG_SDIO_UART=y · line 200

Quoted 7 lines

arch/arm/configs/omap2plus_defconfig +1 -0

@@ -194,6 +194,7 @@ CONFIG_SDIO_UART=y
 CONFIG_MMC_OMAP=y
 CONFIG_MMC_OMAP_HS=y
 CONFIG_RTC_CLASS=y
+CONFIG_RTC_DRV_OMAP=y
 CONFIG_RTC_DRV_TWL92330=y
 CONFIG_RTC_DRV_TWL4030=y
 CONFIG_DMADEVICES=y

Hello,

But this is not enough, we need to change drivers/rtc/Kconfig too. This change was offered in this thread

http://marc.info/?l=linux-arm-kernel&m=135057569913027&w=2

But, may be all this previous rtc-related changes accounted already in some development branch. I just doesn't see it in the current master. In this case, when could we get RTC support in the current kernel?