[PATCH 1/2] rtc: rs5c372: support alarms up to 1 week

[PATCH 1/2] rtc: rs5c372: support alarms up to 1 week

[Daniel González Cabanelas]

The Ricoh R2221x, R2223x, RS5C372, RV5C387A chips can handle 1 week
alarms.

Read the "wday" alarm register and convert it to a date to support up 1
week in our driver.

Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
---
 drivers/rtc/rtc-rs5c372.c | 48 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
index 3bd6eaa0d..94b778c6e 100644
--- a/drivers/rtc/rtc-rs5c372.c
+++ b/drivers/rtc/rtc-rs5c372.c
@@ -393,7 +393,9 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
 	struct i2c_client	*client = to_i2c_client(dev);
 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
-	int			status;
+	int			status, wday_offs;
+	struct rtc_time 	rtc;
+	unsigned long 		alarm_secs;
 
 	status = rs5c_get_regs(rs5c);
 	if (status < 0)
@@ -403,6 +405,30 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 	t->time.tm_sec = 0;
 	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
 	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
+	t->time.tm_wday = ffs(rs5c->regs[RS5C_REG_ALARM_A_WDAY] & 0x7f) - 1;
+
+	/* determine the day, month and year based on alarm wday, taking as a
+	 * reference the current time from the rtc
+	 */
+	status = rs5c372_rtc_read_time(dev, &rtc);
+	if (status < 0)
+		return status;
+
+	wday_offs = t->time.tm_wday - rtc.tm_wday;
+	alarm_secs = mktime64(rtc.tm_year + 1900,
+			      rtc.tm_mon + 1,
+			      rtc.tm_mday + wday_offs,
+			      t->time.tm_hour,
+			      t->time.tm_min,
+			      t->time.tm_sec);
+
+	if (wday_offs < 0 || (wday_offs == 0 &&
+			      (t->time.tm_hour < rtc.tm_hour ||
+			       (t->time.tm_hour == rtc.tm_hour &&
+				t->time.tm_min <= rtc.tm_min))))
+		alarm_secs += 7 * 86400;
+
+	rtc_time64_to_tm(alarm_secs, &t->time);
 
 	/* ... and status */
 	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
@@ -417,12 +443,20 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	struct rs5c372		*rs5c = i2c_get_clientdata(client);
 	int			status, addr, i;
 	unsigned char		buf[3];
+	struct rtc_time 	rtc_tm;
+	unsigned long 		rtc_secs, alarm_secs;
 
-	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
-	if (t->time.tm_mday != -1
-			|| t->time.tm_mon != -1
-			|| t->time.tm_year != -1)
+	/* chip only can handle alarms up to one week in the future*/
+	status = rs5c372_rtc_read_time(dev, &rtc_tm);
+	if (status)
+		return status;
+	rtc_secs = rtc_tm_to_time64(&rtc_tm);
+	alarm_secs = rtc_tm_to_time64(&t->time);
+	if (alarm_secs >= rtc_secs + 7 * 86400) {
+		dev_err(dev, "%s: alarm maximum is one week in the future (%d)\n",
+			__func__, status);
 		return -EINVAL;
+	}
 
 	/* REVISIT: round up tm_sec */
 
@@ -443,7 +477,9 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	/* set alarm */
 	buf[0] = bin2bcd(t->time.tm_min);
 	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
-	buf[2] = 0x7f;	/* any/all days */
+	/* each bit is the day of the week, 0x7f means all days */
+	buf[2] = (t->time.tm_wday >= 0 && t->time.tm_wday < 7) ?
+		  BIT(t->time.tm_wday) : 0x7f;
 
 	for (i = 0; i < sizeof(buf); i++) {
 		addr = RS5C_ADDR(RS5C_REG_ALARM_A_MIN + i);
-- 
2.29.2

Re: [PATCH 1/2] rtc: rs5c372: support alarms up to 1 week

[Alexandre Belloni]

Hello,

On 23/11/2020 11:38:44+0100, Daniel González Cabanelas wrote:
> The Ricoh R2221x, R2223x, RS5C372, RV5C387A chips can handle 1 week
> alarms.
> 
> Read the "wday" alarm register and convert it to a date to support up 1
> week in our driver.
> 
> Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> ---
>  drivers/rtc/rtc-rs5c372.c | 48 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 42 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
> index 3bd6eaa0d..94b778c6e 100644
> --- a/drivers/rtc/rtc-rs5c372.c
> +++ b/drivers/rtc/rtc-rs5c372.c
> @@ -393,7 +393,9 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
>  {
>  	struct i2c_client	*client = to_i2c_client(dev);
>  	struct rs5c372		*rs5c = i2c_get_clientdata(client);
> -	int			status;
> +	int			status, wday_offs;
> +	struct rtc_time 	rtc;

You have a few spaces before tabs, please fix them.

> +	unsigned long 		alarm_secs;
>  
>  	status = rs5c_get_regs(rs5c);
>  	if (status < 0)
> @@ -403,6 +405,30 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
>  	t->time.tm_sec = 0;
>  	t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
>  	t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
> +	t->time.tm_wday = ffs(rs5c->regs[RS5C_REG_ALARM_A_WDAY] & 0x7f) - 1;
> +
> +	/* determine the day, month and year based on alarm wday, taking as a
> +	 * reference the current time from the rtc
> +	 */
> +	status = rs5c372_rtc_read_time(dev, &rtc);
> +	if (status < 0)
> +		return status;
> +
> +	wday_offs = t->time.tm_wday - rtc.tm_wday;

Note that you can not rely on tm_wday being set correctly. The core will
not (currently) enforce that and most tools jut pass a bogus value or 0.
So you need to calculate wday in rs5c372_rtc_set_time.
I'm currently working on a way for the drivers to ask the core to ensure
wday is correct.

> +	alarm_secs = mktime64(rtc.tm_year + 1900,
> +			      rtc.tm_mon + 1,
> +			      rtc.tm_mday + wday_offs,
> +			      t->time.tm_hour,
> +			      t->time.tm_min,
> +			      t->time.tm_sec);
> +
> +	if (wday_offs < 0 || (wday_offs == 0 &&
> +			      (t->time.tm_hour < rtc.tm_hour ||
> +			       (t->time.tm_hour == rtc.tm_hour &&
> +				t->time.tm_min <= rtc.tm_min))))
> +		alarm_secs += 7 * 86400;
> +
> +	rtc_time64_to_tm(alarm_secs, &t->time);
>  
>  	/* ... and status */
>  	t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
> @@ -417,12 +443,20 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>  	struct rs5c372		*rs5c = i2c_get_clientdata(client);
>  	int			status, addr, i;
>  	unsigned char		buf[3];
> +	struct rtc_time 	rtc_tm;
> +	unsigned long 		rtc_secs, alarm_secs;
>  
> -	/* only handle up to 24 hours in the future, like RTC_ALM_SET */
> -	if (t->time.tm_mday != -1
> -			|| t->time.tm_mon != -1
> -			|| t->time.tm_year != -1)
> +	/* chip only can handle alarms up to one week in the future*/
> +	status = rs5c372_rtc_read_time(dev, &rtc_tm);
> +	if (status)
> +		return status;
> +	rtc_secs = rtc_tm_to_time64(&rtc_tm);
> +	alarm_secs = rtc_tm_to_time64(&t->time);
> +	if (alarm_secs >= rtc_secs + 7 * 86400) {
> +		dev_err(dev, "%s: alarm maximum is one week in the future (%d)\n",
> +			__func__, status);

Please avoid adding an error message. It will not be read anyway.

>  		return -EINVAL;

Maybe it is a good opportunity to change to -ERANGE?

> +	}
>  
>  	/* REVISIT: round up tm_sec */
>  
> @@ -443,7 +477,9 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>  	/* set alarm */
>  	buf[0] = bin2bcd(t->time.tm_min);
>  	buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
> -	buf[2] = 0x7f;	/* any/all days */
> +	/* each bit is the day of the week, 0x7f means all days */
> +	buf[2] = (t->time.tm_wday >= 0 && t->time.tm_wday < 7) ?
> +		  BIT(t->time.tm_wday) : 0x7f;

Here, you also need to calculate buf[2] from t->time.tm_mday instead of
relying on t->time.tm_wday.


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH 1/2] rtc: rs5c372: support alarms up to 1 week

[Daniel González Cabanelas]

Hi Alexandre,

El mar, 12 ene 2021 a las 23:08, Alexandre Belloni
(<alexandre.belloni@bootlin.com>) escribió:
>
> Hello,
>
> On 23/11/2020 11:38:44+0100, Daniel González Cabanelas wrote:
> > The Ricoh R2221x, R2223x, RS5C372, RV5C387A chips can handle 1 week
> > alarms.
> >
> > Read the "wday" alarm register and convert it to a date to support up 1
> > week in our driver.
> >
> > Signed-off-by: Daniel González Cabanelas <dgcbueu@gmail.com>
> > ---
> >  drivers/rtc/rtc-rs5c372.c | 48 ++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 42 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-rs5c372.c b/drivers/rtc/rtc-rs5c372.c
> > index 3bd6eaa0d..94b778c6e 100644
> > --- a/drivers/rtc/rtc-rs5c372.c
> > +++ b/drivers/rtc/rtc-rs5c372.c
> > @@ -393,7 +393,9 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
> >  {
> >       struct i2c_client       *client = to_i2c_client(dev);
> >       struct rs5c372          *rs5c = i2c_get_clientdata(client);
> > -     int                     status;
> > +     int                     status, wday_offs;
> > +     struct rtc_time         rtc;
>
> You have a few spaces before tabs, please fix them.
>
Ok

> > +     unsigned long           alarm_secs;
> >
> >       status = rs5c_get_regs(rs5c);
> >       if (status < 0)
> > @@ -403,6 +405,30 @@ static int rs5c_read_alarm(struct device *dev, struct rtc_wkalrm *t)
> >       t->time.tm_sec = 0;
> >       t->time.tm_min = bcd2bin(rs5c->regs[RS5C_REG_ALARM_A_MIN] & 0x7f);
> >       t->time.tm_hour = rs5c_reg2hr(rs5c, rs5c->regs[RS5C_REG_ALARM_A_HOURS]);
> > +     t->time.tm_wday = ffs(rs5c->regs[RS5C_REG_ALARM_A_WDAY] & 0x7f) - 1;
> > +
> > +     /* determine the day, month and year based on alarm wday, taking as a
> > +      * reference the current time from the rtc
> > +      */
> > +     status = rs5c372_rtc_read_time(dev, &rtc);
> > +     if (status < 0)
> > +             return status;
> > +
> > +     wday_offs = t->time.tm_wday - rtc.tm_wday;
>
> Note that you can not rely on tm_wday being set correctly. The core will
> not (currently) enforce that and most tools jut pass a bogus value or 0.
> So you need to calculate wday in rs5c372_rtc_set_time.

will this code be enough for the set_time function?
-------------snip-------------
int wday;
struct rtc_time calc_tm;

/* wday calculate */
rtc_time64_to_tm(rtc_tm_to_time64(tm), &calc_tm);
wday = calc_tm.tm_wday;

buf[3] = bin2bcd(wday);
-------------snip-------------

> I'm currently working on a way for the drivers to ask the core to ensure
> wday is correct.
>
> > +     alarm_secs = mktime64(rtc.tm_year + 1900,
> > +                           rtc.tm_mon + 1,
> > +                           rtc.tm_mday + wday_offs,
> > +                           t->time.tm_hour,
> > +                           t->time.tm_min,
> > +                           t->time.tm_sec);
> > +
> > +     if (wday_offs < 0 || (wday_offs == 0 &&
> > +                           (t->time.tm_hour < rtc.tm_hour ||
> > +                            (t->time.tm_hour == rtc.tm_hour &&
> > +                             t->time.tm_min <= rtc.tm_min))))
> > +             alarm_secs += 7 * 86400;
> > +
> > +     rtc_time64_to_tm(alarm_secs, &t->time);
> >
> >       /* ... and status */
> >       t->enabled = !!(rs5c->regs[RS5C_REG_CTRL1] & RS5C_CTRL1_AALE);
> > @@ -417,12 +443,20 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> >       struct rs5c372          *rs5c = i2c_get_clientdata(client);
> >       int                     status, addr, i;
> >       unsigned char           buf[3];
> > +     struct rtc_time         rtc_tm;
> > +     unsigned long           rtc_secs, alarm_secs;
> >
> > -     /* only handle up to 24 hours in the future, like RTC_ALM_SET */
> > -     if (t->time.tm_mday != -1
> > -                     || t->time.tm_mon != -1
> > -                     || t->time.tm_year != -1)
> > +     /* chip only can handle alarms up to one week in the future*/
> > +     status = rs5c372_rtc_read_time(dev, &rtc_tm);
> > +     if (status)
> > +             return status;
> > +     rtc_secs = rtc_tm_to_time64(&rtc_tm);
> > +     alarm_secs = rtc_tm_to_time64(&t->time);
> > +     if (alarm_secs >= rtc_secs + 7 * 86400) {
> > +             dev_err(dev, "%s: alarm maximum is one week in the future (%d)\n",
> > +                     __func__, status);
>
> Please avoid adding an error message. It will not be read anyway.
>
> >               return -EINVAL;
>
> Maybe it is a good opportunity to change to -ERANGE?
>
Ok

> > +     }
> >
> >       /* REVISIT: round up tm_sec */
> >
> > @@ -443,7 +477,9 @@ static int rs5c_set_alarm(struct device *dev, struct rtc_wkalrm *t)
> >       /* set alarm */
> >       buf[0] = bin2bcd(t->time.tm_min);
> >       buf[1] = rs5c_hr2reg(rs5c, t->time.tm_hour);
> > -     buf[2] = 0x7f;  /* any/all days */
> > +     /* each bit is the day of the week, 0x7f means all days */
> > +     buf[2] = (t->time.tm_wday >= 0 && t->time.tm_wday < 7) ?
> > +               BIT(t->time.tm_wday) : 0x7f;
>
> Here, you also need to calculate buf[2] from t->time.tm_mday instead of
> relying on t->time.tm_wday.

I can't se how to calculate the wday using t->time.tm_mday. Again can
I use this?:
-------------snip-------------
rtc_time64_to_tm(rtc_tm_to_time64(tm), &calc_tm);
wday = calc_tm.tm_wday;
-------------snip-------------

Regards
Daniel

>
>
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com