[PATCH] rtc: OMAP: Add support for rtc-only mode

From: Keerthy
Date: Wed Jul 04 2018 - 02:34:35 EST

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Prepare rtc driver for rtc-only mode. This involes splitting the power-off
function so that an external driver can initiate the programming of
setting the power_off to be triggered in the next second.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
---
drivers/rtc/interface.c | 12 ++++
drivers/rtc/rtc-omap.c | 164 ++++++++++++++++++++++++++++++++++--------------
include/linux/rtc.h | 2 +
3 files changed, 130 insertions(+), 48 deletions(-)

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 6d4012d..d8b70f0 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -1139,3 +1139,15 @@ int rtc_set_offset(struct rtc_device *rtc, long offset)
trace_rtc_set_offset(offset, ret);
return ret;
}
+
+/**
+ * rtc_power_off_program - Some of the rtc are hooked on to PMIC_EN
+ * line and can be used to power off the SoC.
+ *
+ * Kernel interface to program rtc to power off
+ */
+void rtc_power_off_program(struct rtc_device *rtc)
+{
+ rtc->ops->power_off_program(rtc->dev.parent);
+}
+EXPORT_SYMBOL_GPL(rtc_power_off_program);
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index 3908639..4dcee1c 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -29,6 +29,7 @@
#include <linux/pinctrl/pinconf-generic.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/regulator/machine.h>
#include <linux/rtc.h>

/*
@@ -131,6 +132,8 @@
#define KICK0_VALUE 0x83e70b13
#define KICK1_VALUE 0x95a4f1e0

+#define SHUTDOWN_TIME_SEC 1
+
struct omap_rtc;

struct omap_rtc_device_type {
@@ -415,6 +418,77 @@ static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)

static struct omap_rtc *omap_rtc_power_off_rtc;

+/**
+ * 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.
+ */
+void omap_rtc_power_off_program(struct device *dev)
+{
+ u32 val;
+ struct rtc_time tm;
+ unsigned long time;
+ int seconds;
+
+ omap_rtc_power_off_rtc->type->unlock(omap_rtc_power_off_rtc);
+
+ /* Clear any existing ALARM2 event */
+ rtc_writel(omap_rtc_power_off_rtc, OMAP_RTC_STATUS_REG,
+ OMAP_RTC_STATUS_ALARM2);
+
+ pr_info("System will go to power_off state in approx. %d second\n",
+ SHUTDOWN_TIME_SEC);
+
+again:
+ /* Read rtc time */
+ tm.tm_sec = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_SECONDS_REG);
+ seconds = tm.tm_sec;
+ tm.tm_min = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_MINUTES_REG);
+ tm.tm_hour = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_HOURS_REG);
+ tm.tm_mday = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_DAYS_REG);
+ tm.tm_mon = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_MONTHS_REG);
+ tm.tm_year = rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_YEARS_REG);
+ bcd2tm(&tm);
+
+ /* Convert Gregorian date to seconds since 01-01-1970 00:00:00 */
+ rtc_tm_to_time(&tm, &time);
+
+ /* Convert seconds since 01-01-1970 00:00:00 to Gregorian date */
+ rtc_time_to_tm(time + SHUTDOWN_TIME_SEC, &tm);
+
+ if (tm2bcd(&tm) < 0)
+ return;
+
+ /* After wait_not_busy, we have at least 15us until the next second. */
+ rtc_wait_not_busy(omap_rtc_power_off_rtc);
+
+ /* Our calculations started right before the rollover, try again */
+ if (seconds != rtc_read(omap_rtc_power_off_rtc, OMAP_RTC_SECONDS_REG))
+ goto again;
+
+ /*
+ * pmic_pwr_enable is controlled by means of ALARM2 event. So here
+ * programming alarm2 expiry time and enabling alarm2 interrupt
+ */
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_SECONDS_REG,
+ tm.tm_sec);
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_MINUTES_REG,
+ tm.tm_min);
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_HOURS_REG,
+ tm.tm_hour);
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_DAYS_REG,
+ tm.tm_mday);
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_MONTHS_REG,
+ tm.tm_mon);
+ rtc_write(omap_rtc_power_off_rtc, OMAP_RTC_ALARM2_YEARS_REG,
+ tm.tm_year);
+
+ /* Enable alarm2 interrupt */
+ val = rtc_readl(omap_rtc_power_off_rtc, OMAP_RTC_INTERRUPTS_REG);
+ rtc_writel(omap_rtc_power_off_rtc, OMAP_RTC_INTERRUPTS_REG, val |
+ OMAP_RTC_INTERRUPTS_IT_ALARM2);
+}
+
/*
* omap_rtc_poweroff: RTC-controlled power off
*
@@ -431,45 +505,19 @@ static int omap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
*/
static void omap_rtc_power_off(void)
{
- struct omap_rtc *rtc = omap_rtc_power_off_rtc;
- struct rtc_time tm;
- unsigned long now;
+ struct rtc_device *rtc = omap_rtc_power_off_rtc->rtc;
u32 val;

- rtc->type->unlock(rtc);
- /* enable pmic_power_en control */
- val = rtc_readl(rtc, OMAP_RTC_PMIC_REG);
- rtc_writel(rtc, OMAP_RTC_PMIC_REG, val | OMAP_RTC_PMIC_POWER_EN_EN);
-
- /* set alarm two seconds from now */
- omap_rtc_read_time_raw(rtc, &tm);
- bcd2tm(&tm);
- rtc_tm_to_time(&tm, &now);
- rtc_time_to_tm(now + 2, &tm);
-
- if (tm2bcd(&tm) < 0) {
- dev_err(&rtc->rtc->dev, "power off failed\n");
- return;
- }
-
- rtc_wait_not_busy(rtc);
+ regulator_suspend_prepare(PM_SUSPEND_MAX);
+ omap_rtc_power_off_rtc->type->unlock(omap_rtc_power_off_rtc);
+ omap_rtc_power_off_program(rtc->dev.parent);

- rtc_write(rtc, OMAP_RTC_ALARM2_SECONDS_REG, tm.tm_sec);
- rtc_write(rtc, OMAP_RTC_ALARM2_MINUTES_REG, tm.tm_min);
- rtc_write(rtc, OMAP_RTC_ALARM2_HOURS_REG, tm.tm_hour);
- rtc_write(rtc, OMAP_RTC_ALARM2_DAYS_REG, tm.tm_mday);
- rtc_write(rtc, OMAP_RTC_ALARM2_MONTHS_REG, tm.tm_mon);
- rtc_write(rtc, OMAP_RTC_ALARM2_YEARS_REG, tm.tm_year);
-
- /*
- * enable ALARM2 interrupt
- *
- * NOTE: this fails on AM3352 if rtc_write (writeb) is used
- */
- val = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
- rtc_writel(rtc, OMAP_RTC_INTERRUPTS_REG,
- val | OMAP_RTC_INTERRUPTS_IT_ALARM2);
- rtc->type->lock(rtc);
+ /* Set PMIC power enable and EXT_WAKEUP in case PB power on is used */
+ 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 two seconds) and external PMIC to
@@ -477,6 +525,17 @@ static void omap_rtc_power_off(void)
* (e.g. debounce circuits).
*/
mdelay(2500);
+
+ pr_err("rtc_power_off failed, bailing out.\n");
+}
+
+static void omap_rtc_cleanup_pm_power_off(struct omap_rtc *rtc)
+{
+ if (pm_power_off == omap_rtc_power_off &&
+ omap_rtc_power_off_rtc == rtc) {
+ pm_power_off = NULL;
+ omap_rtc_power_off_rtc = NULL;
+ }
}

static const struct rtc_class_ops omap_rtc_ops = {
@@ -485,6 +544,7 @@ static void omap_rtc_power_off(void)
.read_alarm = omap_rtc_read_alarm,
.set_alarm = omap_rtc_set_alarm,
.alarm_irq_enable = omap_rtc_alarm_irq_enable,
+ .power_off_program = omap_rtc_power_off_program,
};

static const struct omap_rtc_device_type omap_rtc_default_type = {
@@ -838,6 +898,11 @@ static int omap_rtc_probe(struct platform_device *pdev)
rtc->type->lock(rtc);

device_init_wakeup(&pdev->dev, true);
+ omap_rtc_power_off_rtc = rtc;
+
+ if (rtc->is_pmic_controller)
+ if (!pm_power_off)
+ pm_power_off = omap_rtc_power_off;

rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc)) {
@@ -887,6 +952,7 @@ static int omap_rtc_probe(struct platform_device *pdev)
return 0;

err:
+ omap_rtc_cleanup_pm_power_off(rtc);
clk_disable_unprepare(rtc->clk);
device_init_wakeup(&pdev->dev, false);
rtc->type->lock(rtc);
@@ -901,11 +967,7 @@ static int omap_rtc_remove(struct platform_device *pdev)
struct omap_rtc *rtc = platform_get_drvdata(pdev);
u8 reg;

- if (pm_power_off == omap_rtc_power_off &&
- omap_rtc_power_off_rtc == rtc) {
- pm_power_off = NULL;
- omap_rtc_power_off_rtc = NULL;
- }
+ omap_rtc_cleanup_pm_power_off(rtc);

device_init_wakeup(&pdev->dev, 0);

@@ -993,14 +1055,20 @@ static void omap_rtc_shutdown(struct platform_device *pdev)
struct omap_rtc *rtc = platform_get_drvdata(pdev);
u8 mask;

- /*
- * Keep the ALARM interrupt enabled to allow the system to power up on
- * alarm events.
- */
rtc->type->unlock(rtc);
- mask = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
- mask &= OMAP_RTC_INTERRUPTS_IT_ALARM;
- rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, mask);
+ /* If rtc does not control PMIC then no need to enable ALARM */
+ if (!rtc->is_pmic_controller) {
+ rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0);
+ } else {
+ /*
+ * Keep the ALARM interrupt enabled to allow the system to
+ * power up on alarm events.
+ */
+ mask = rtc_read(rtc, OMAP_RTC_INTERRUPTS_REG);
+ mask &= OMAP_RTC_INTERRUPTS_IT_ALARM;
+ rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, mask);
+ }
+
rtc->type->lock(rtc);
}

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 6268208..f17bc6a 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -85,6 +85,7 @@ struct rtc_class_ops {
int (*alarm_irq_enable)(struct device *, unsigned int enabled);
int (*read_offset)(struct device *, long *offset);
int (*set_offset)(struct device *, long offset);
+ void (*power_off_program)(struct device *dev);
};

typedef struct rtc_task {
@@ -229,6 +230,7 @@ int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
int rtc_read_offset(struct rtc_device *rtc, long *offset);
int rtc_set_offset(struct rtc_device *rtc, long offset);
void rtc_timer_do_work(struct work_struct *work);
+void rtc_power_off_program(struct rtc_device *rtc);

static inline bool is_leap_year(unsigned int year)
{
--
1.9.1

Next message: Sekhar Nori: "Re: [PATCH v3 00/13] ARM: davinci: remove duplicate aemif support"
Previous message: Mike Rapoport: "[PATCH v2 2/3] m68k/page_no.h: force __va argument to be unsigned long"
Next in thread: Alexandre Belloni: "Re: [PATCH] rtc: OMAP: Add support for rtc-only mode"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]