Re: [RFC PATCH v1 11/13] rtc: bd70528: Initial support for ROHM bd70528 RTC

Guenter Roeck
2019-01-22T14:48:39Z

On 1/22/19 1:47 AM, Matti Vaittinen wrote:
> Support RTC block in ROHM bd70528 power management IC. Support
> getting and setting the time and date as well as arming an alarm
> which can also be used to wake the PMIC from standby state.
>
> HW supports wake interrupt only for the next 24 hours (sec, minute
> and hour information only) so we limit also the alarm interrupt to
> this 24 hours for the sake of consistency.
>
> Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
> ---
> drivers/rtc/Kconfig | 8 +
> drivers/rtc/Makefile | 1 +
> drivers/rtc/rtc-bd70528.c | 439 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 448 insertions(+)
> create mode 100644 drivers/rtc/rtc-bd70528.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 225b0b8516f3..df6211cbd83f 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -487,6 +487,14 @@ config RTC_DRV_M41T80_WDT
> help
> If you say Y here you will get support for the
> watchdog timer in the ST M41T60 and M41T80 RTC chips series.
> +config RTC_DRV_BD70528
> + tristate "ROHM BD70528 PMIC RTC"
> + help
> + If you say Y here you will get support for the RTC
> + on ROHM BD70528 Power Management IC.
> +
> + This driver can also be built as a module. If so, the module
> + will be called rtc-bd70528.
>
> config RTC_DRV_BQ32K
> tristate "TI BQ32000"
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index df022d820bee..740b13840913 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_RTC_DRV_ASM9260) += rtc-asm9260.o
> obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
> obj-$(CONFIG_RTC_DRV_AT91SAM9) += rtc-at91sam9.o
> obj-$(CONFIG_RTC_DRV_AU1XXX) += rtc-au1xxx.o
> +obj-$(CONFIG_RTC_DRV_BD70528) += rtc-bd70528.o
> obj-$(CONFIG_RTC_DRV_BQ32K) += rtc-bq32k.o
> obj-$(CONFIG_RTC_DRV_BQ4802) += rtc-bq4802.o
> obj-$(CONFIG_RTC_DRV_BRCMSTB) += rtc-brcmstb-waketimer.o
> diff --git a/drivers/rtc/rtc-bd70528.c b/drivers/rtc/rtc-bd70528.c
> new file mode 100644
> index 000000000000..7c7e1f8769e8
> --- /dev/null
> +++ b/drivers/rtc/rtc-bd70528.c
> @@ -0,0 +1,439 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +//
> +// Copyright (C) 2018 ROHM Semiconductors
> +//
> +// RTC driver for ROHM BD70528 PMIC
> +
> +#include <linux/bcd.h>
> +#include <linux/mfd/rohm-bd70528.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/rtc.h>
> +
> +/*
> + * We read regs RTC_SEC => RTC_YEAR
> + * this struct is ordered according to chip registers.
> + * Keep it u8 only to avoid padding issues.
> + */
> +struct bd70528_rtc_day {
> + u8 sec;
> + u8 min;
> + u8 hour;
> +};
> +struct bd70528_rtc_data {
> + struct bd70528_rtc_day time;
> + u8 week;
> + u8 day;
> + u8 month;
> + u8 year;
> +};
> +struct bd70528_rtc_wake {
> + struct bd70528_rtc_day time;
> + u8 ctrl;
> +};
> +struct bd70528_rtc_alm {
> + struct bd70528_rtc_data data;
> + u8 alm_mask;
> + u8 alm_repeat;
> +};
> +
> +static int bd70528_set_wake(struct bd70528 *bd70528,
> + int enable, int *old_state)
> +{
> + int ret;
> + unsigned int ctrl_reg;
> +
> + ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WAKE_EN, &ctrl_reg);
> + if (ret)
> + return ret;
> +
> + if (old_state) {
> + if (ctrl_reg & BD70528_MASK_WAKE_EN)
> + *old_state |= BD70528_WAKE_STATE_BIT;
> + else
> + *old_state &= ~BD70528_WAKE_STATE_BIT;
> +
> + if ((!enable) == (!(*old_state & BD70528_WAKE_STATE_BIT)))
> + return 0;
> + }
> +
> + if (enable)
> + ctrl_reg |= BD70528_MASK_WAKE_EN;
> + else
> + ctrl_reg &= ~BD70528_MASK_WAKE_EN;
> +
> + return regmap_write(bd70528->chip.regmap, BD70528_REG_WAKE_EN,
> + ctrl_reg);
> +}
> +
> +static int bd70528_set_elapsed_tmr(struct bd70528 *bd70528,
> + int enable, int *old_state)
> +{
> + int ret;
> + unsigned int ctrl_reg;
> +
> + /*
> + * TBD
> + * What is the purpose of elapsed timer ?
> + * Is the timeout registers counting down, or is the disable - re-enable
> + * going to restart the elapsed-time counting? If counting is restarted
> + * the timeout should be decreased by the amount of time that has
> + * elapsed since starting the timer. Maybe we should store the monotonic
> + * clock value when timer is started so that if RTC is set while timer
> + * is armed we could do the compensation. This is a hack if RTC/system
> + * clk are drifting. OTOH, RTC controlled via I2C is in any case
> + * inaccurate...
> + */
> + ret = regmap_read(bd70528->chip.regmap, BD70528_REG_ELAPSED_TIMER_EN,
> + &ctrl_reg);
> + if (ret)
> + return ret;
> +
> + if (old_state) {
> + if (ctrl_reg & BD70528_MASK_ELAPSED_TIMER_EN)
> + *old_state |= BD70528_ELAPSED_STATE_BIT;
> + else
> + *old_state &= ~BD70528_ELAPSED_STATE_BIT;
> +
> + if ((!enable) == (!(*old_state & BD70528_ELAPSED_STATE_BIT)))
> + return 0;
> + }
> +
> + if (enable)
> + ctrl_reg |= BD70528_MASK_ELAPSED_TIMER_EN;
> + else
> + ctrl_reg &= ~BD70528_MASK_ELAPSED_TIMER_EN;
> +
> + return regmap_write(bd70528->chip.regmap, BD70528_REG_ELAPSED_TIMER_EN,
> + ctrl_reg);
> +}
> +
> +static int bd70528_set_rtc_based_timers(struct bd70528 *bd70528, int new_state,
> + int *old_state)

Passed parameter is an int, not int *. I'd be quite surprised if this compiles
without warning.

> +{
> + int ret;
> +
> + ret = bd70528->wdt_set(bd70528, new_state & BD70528_WDT_STATE_BIT,
> + old_state);
> + if (ret) {
> + dev_err(bd70528->chip.dev,
> + "Failed to disable WDG for RTC setting (%d)\n", ret);
> + return ret;
> + }
> + ret = bd70528_set_elapsed_tmr(bd70528,
> + new_state & BD70528_ELAPSED_STATE_BIT,
> + old_state);
> + if (ret) {
> + dev_err(bd70528->chip.dev,
> + "Failed to disable 'elapsed timer' for RTC setting\n");
> + return ret;
> + }
> + ret = bd70528_set_wake(bd70528, new_state & BD70528_WAKE_STATE_BIT,
> + old_state);
> + if (ret) {
> + dev_err(bd70528->chip.dev,
> + "Failed to disable 'wake timer' for RTC setting\n");
> + return ret;
> + }
> +
> + return ret;
> +}
> +
> +static int bd70528_re_enable_rtc_based_timers(struct bd70528 *bd70528,
> + int old_state)
> +{
> + if (bd70528->rtc_timer_lock)
> + mutex_unlock(bd70528->rtc_timer_lock);
> +
Unlock before calling bd70528_set_rtc_based_timers is odd, especially since it
is called after locking below.

> + return bd70528_set_rtc_based_timers(bd70528, old_state, NULL);
> +}
> +
> +static int bd70528_disable_rtc_based_timers(struct bd70528 *bd70528,
> + int *old_state)
> +{
> + if (bd70528->rtc_timer_lock)
> + mutex_lock(bd70528->rtc_timer_lock);
> +
> + return bd70528_set_rtc_based_timers(bd70528, 0, old_state);
> +}
> +
> +static inline void tmday2rtc(struct rtc_time *t, struct bd70528_rtc_day *d)
> +{
> + d->sec &= ~BD70528_MASK_RTC_SEC;
> + d->min &= ~BD70528_MASK_RTC_MINUTE;
> + d->hour &= ~BD70528_MASK_RTC_HOUR;
> + d->sec |= bin2bcd(t->tm_sec);
> + d->min |= bin2bcd(t->tm_min);
> + d->hour |= bin2bcd(t->tm_hour);
> +}
> +
> +static inline void tm2rtc(struct rtc_time *t, struct bd70528_rtc_data *r)
> +{
> + r->day &= ~BD70528_MASK_RTC_DAY;
> + r->week &= ~BD70528_MASK_RTC_WEEK;
> + r->month &= ~BD70528_MASK_RTC_MONTH;
> + /*
> + * PM and 24H bits are not used by Wake - thus iwe clear them
> + * here and not in tmday2rtc() which is also used by wake.
> + */
> + r->time.hour &= ~(BD70528_MASK_RTC_HOUR_PM | BD70528_MASK_RTC_HOUR_24H);
> +
> + tmday2rtc(t, &r->time);
> + /*
> + * We do always set time in 24H mode.
> + */
> + r->time.hour |= BD70528_MASK_RTC_HOUR_24H;
> + r->day |= bin2bcd(t->tm_mday);
> + r->week |= bin2bcd(t->tm_wday);
> + r->month |= bin2bcd(t->tm_mon + 1);
> + r->year = bin2bcd(t->tm_year-100);
> +}
> +
> +static inline void rtc2tm(struct bd70528_rtc_data *r, struct rtc_time *t)
> +{
> + t->tm_sec = bcd2bin(r->time.sec & BD70528_MASK_RTC_SEC);
> + t->tm_min = bcd2bin(r->time.min & BD70528_MASK_RTC_MINUTE);
> + t->tm_hour = bcd2bin(r->time.hour & BD70528_MASK_RTC_HOUR);
> + /*
> + * If RTC is in 12H mode, then bit BD70528_MASK_RTC_HOUR_PM
> + * is not BCD value but tells whether it is AM or PM
> + */
> + if (!(r->time.hour & BD70528_MASK_RTC_HOUR_24H)) {
> + t->tm_hour %= 12;
> + if (r->time.hour & BD70528_MASK_RTC_HOUR_PM)
> + t->tm_hour += 12;
> + }
> + t->tm_mday = bcd2bin(r->day & BD70528_MASK_RTC_DAY);
> + t->tm_mon = bcd2bin(r->month & BD70528_MASK_RTC_MONTH) - 1;
> + t->tm_year = 100 + bcd2bin(r->year & BD70528_MASK_RTC_YEAR);
> + t->tm_wday = bcd2bin(r->week & BD70528_MASK_RTC_WEEK);
> +}
> +
> +static int bd70528_set_alarm(struct device *dev, struct rtc_wkalrm *a)
> +{
> + struct bd70528 *bd70528 = dev_get_drvdata(dev);
> + struct bd70528_rtc_wake wake;
> + struct bd70528_rtc_alm alm;
> + int ret;
> +
> + ret = regmap_bulk_read(bd70528->chip.regmap, BD70528_REG_RTC_WAKE_START,
> + &wake, sizeof(wake));
> + if (ret) {
> + dev_err(dev, "Failed to read wake regs\n");
> + return ret;
> + }
> +
> + ret = regmap_bulk_read(bd70528->chip.regmap, BD70528_REG_RTC_ALM_START,
> + &alm, sizeof(alm));
> + if (ret) {
> + dev_err(dev, "Failed to read alarm regs\n");
> + return ret;
> + }
> +
> + tm2rtc(&a->time, &alm.data);
> + tmday2rtc(&a->time, &wake.time);
> +
> + if (a->enabled) {
> + alm.alm_mask &= ~BD70528_MASK_ALM_EN;
> + wake.ctrl |= BD70528_MASK_WAKE_EN;
> + } else {
> + alm.alm_mask |= BD70528_MASK_ALM_EN;
> + wake.ctrl &= ~BD70528_MASK_WAKE_EN;
> + }
> +
> + ret = regmap_bulk_write(bd70528->chip.regmap,
> + BD70528_REG_RTC_WAKE_START, &wake,
> + sizeof(wake));
> + if (ret) {
> + dev_err(dev, "Failed to set wake time\n");
> + return ret;
> + }
> + ret = regmap_bulk_write(bd70528->chip.regmap, BD70528_REG_RTC_ALM_START,
> + &alm, sizeof(alm));
> + if (ret)
> + dev_err(dev, "Failed to set alarm time\n");
> +
> + return ret;
> +}
> +
> +static int bd70528_read_alarm(struct device *dev, struct rtc_wkalrm *a)
> +{
> + struct bd70528 *bd70528 = dev_get_drvdata(dev);
> + struct bd70528_rtc_alm alm;
> + int ret;
> +
> + ret = regmap_bulk_read(bd70528->chip.regmap, BD70528_REG_RTC_ALM_START,
> + &alm, sizeof(alm));
> + if (ret) {
> + dev_err(dev, "Failed to read alarm regs\n");
> + return ret;
> + }
> +
> + rtc2tm(&alm.data, &a->time);
> + a->time.tm_mday = -1;
> + a->time.tm_mon = -1;
> + a->time.tm_year = -1;
> + if (alm.alm_mask & BD70528_MASK_ALM_EN)
> + a->enabled = 0;
> + else
> + a->enabled = 1;
> +
> + a->pending = 0;
> +
> + return 0;
> +}
> +
> +static int bd70528_set_time(struct device *dev, struct rtc_time *t)
> +{
> + int ret, old_states;
> + struct bd70528_rtc_data rtc_data;
> + struct bd70528 *bd70528 = dev_get_drvdata(dev);
> +
> + ret = bd70528_disable_rtc_based_timers(bd70528, &old_states);
> +
> + ret = regmap_bulk_read(bd70528->chip.regmap,
> + BD70528_REG_RTC_START, &rtc_data,
> + sizeof(rtc_data));
> +
> + tm2rtc(t, &rtc_data);
> +
> + ret = regmap_bulk_write(bd70528->chip.regmap,
> + BD70528_REG_RTC_START, &rtc_data,
> + sizeof(rtc_data));
> +
> + ret = bd70528_re_enable_rtc_based_timers(bd70528, old_states);
> +
> + return 0;
> +}
> +static int bd70528_get_time(struct device *dev, struct rtc_time *t)
> +{
> + struct bd70528 *bd70528 = dev_get_drvdata(dev);
> + struct bd70528_rtc_data rtc_data;
> + int ret;
> +
> + /* read the RTC date and time registers all at once */
> + ret = regmap_bulk_read(bd70528->chip.regmap,
> + BD70528_REG_RTC_START, &rtc_data,
> + sizeof(rtc_data));
> + if (ret) {
> + dev_err(dev, "Failed to read RTC time (err %d)\n", ret);
> + return ret;
> + }
> +
> + rtc2tm(&rtc_data, t);
> +
> + return 0;
> +}
> +
> +static const struct rtc_class_ops bd70528_rtc_ops = {
> + .read_time = bd70528_get_time,
> + .set_time = bd70528_set_time,
> + .read_alarm = bd70528_read_alarm,
> + .set_alarm = bd70528_set_alarm,
> +};
> +
> +static irqreturn_t alm_hndlr(int irq, void *data)
> +{
> + struct rtc_device *rtc = data;
> +
> + rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF | RTC_PF);
> + return IRQ_HANDLED;
> +}
> +
> +static int bd70528_probe(struct platform_device *pdev)
> +{
> + struct bd70528 *bd70528;
> + struct bd70528 *tmp;
> + int ret;
> + struct rtc_device *rtc;
> + int irq;
> + unsigned int hr;
> +
> + tmp = dev_get_drvdata(pdev->dev.parent);
> + if (!tmp) {
> + dev_err(&pdev->dev, "No MFD driver data\n");
> + return -EINVAL;
> + }
> + bd70528 = devm_kzalloc(&pdev->dev, sizeof(*bd70528), GFP_KERNEL);
> + if (!bd70528)
> + return -ENOMEM;
> +
> + *bd70528 = *tmp;
> + bd70528->chip.dev = &pdev->dev;
> +
> + irq = platform_get_irq_byname(pdev, "bd70528-rtc-alm");
> +
> + if (irq < 0) {
> + dev_err(&pdev->dev, "Failed to get irq\n");
> + return irq;
> + }
> +
> + platform_set_drvdata(pdev, bd70528);
> +
> +
> + ret = regmap_read(bd70528->chip.regmap, BD70528_REG_RTC_HOUR, &hr);
> +
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to reag RTC clock\n");
> + return ret;
> + }
> +
> + if (!(hr & BD70528_MASK_RTC_HOUR_24H)) {
> + struct rtc_time t;
> +
> + ret = bd70528_get_time(&pdev->dev, &t);
> + if (ret)
> + return ret;
> +
> + ret = bd70528_set_time(&pdev->dev, &t);
> + if (ret)
> + return ret;
> + }
> +
> + if (ret) {
> + dev_err(&pdev->dev, "Setting 24H clock for RTC failed\n");
> + return ret;
> + }
> +
> + device_set_wakeup_capable(&pdev->dev, true);
> + device_wakeup_enable(&pdev->dev);
> + rtc = devm_rtc_device_register(&pdev->dev, "bd70528-rtc",
> + &bd70528_rtc_ops, THIS_MODULE);
> + if (IS_ERR(rtc)) {
> + dev_err(&pdev->dev, "Registering RTC failed\n");
> + return PTR_ERR(rtc);
> + }
> +
> + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, &alm_hndlr,
> + IRQF_ONESHOT, "bd70528-rtc", rtc);
> +
> + /*
> + * BD70528 irq controller is not touching the main mask register.
> + * So enable the RTC block interrupts at main level. We can just
> + * leave them enabled as irq-controller should disable irqs
> + * from sub-registers when IRQ is disabled or freed.
> + */
> + ret = regmap_update_bits(bd70528->chip.regmap,
> + BD70528_REG_INT_MAIN,
> + BD70528_INT_RTC_MASK, 0);
> +
> + if (ret)
> + dev_err(&pdev->dev, "Failed to enable RTC interrupts\n");
> +
> + return ret;
> +}
> +
> +static struct platform_driver bd70528_rtc = {
> + .driver = {
> + .name = "bd70528-rtc"
> + },
> + .probe = bd70528_probe,
> +};
> +
> +module_platform_driver(bd70528_rtc);
> +
> +MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
> +MODULE_DESCRIPTION("BD70528 RTC driver");
> +MODULE_LICENSE("GPL");
>