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

From: Alexandre Belloni
Date: Wed Jul 04 2018 - 03:41:20 EST

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In reply to: Keerthy: "[PATCH] rtc: OMAP: Add support for rtc-only mode"
Next in thread: Keerthy: "Re: [PATCH] rtc: OMAP: Add support for rtc-only mode"
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Hi,

On 04/07/2018 12:03:45+0530, Keerthy wrote:
> 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.
>

I'm sorry, I don't see the point, can't you use
of_device_is_system_power_controller and set the correct pm_power_off
callback?

> 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
>

--
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

Next message: Geert Uytterhoeven: "Re: [PATCH v2 3/3] m68k: switch to MEMBLOCK + NO_BOOTMEM"
Previous message: Thomas Gleixner: "Re: [PATCH] x86/mm: fix cpu stuck issue in __change_page_attr_set_clr"
In reply to: Keerthy: "[PATCH] rtc: OMAP: Add support for rtc-only mode"
Next in thread: Keerthy: "Re: [PATCH] rtc: OMAP: Add support for rtc-only mode"
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