2020-05-05 20:15:27

by Alexandre Belloni

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Subject: [PATCH 1/5] rtc: add new VL flag for backup switchover

A new flag RTC_VL_BACKUP_SWITCH means that a backup switchover happened
since last flag clear.

Signed-off-by: Alexandre Belloni <[email protected]>
---
include/uapi/linux/rtc.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/rtc.h b/include/uapi/linux/rtc.h
index 83bba58d47f4..fa9aff91cbf2 100644
--- a/include/uapi/linux/rtc.h
+++ b/include/uapi/linux/rtc.h
@@ -99,6 +99,7 @@ struct rtc_pll_info {
#define RTC_VL_BACKUP_LOW _BITUL(1) /* Backup voltage is low */
#define RTC_VL_BACKUP_EMPTY _BITUL(2) /* Backup empty or not present */
#define RTC_VL_ACCURACY_LOW _BITUL(3) /* Voltage is low, RTC accuracy is reduced */
+#define RTC_VL_BACKUP_SWITCH _BITUL(4) /* Backup switchover happened */

#define RTC_VL_READ _IOR('p', 0x13, unsigned int) /* Voltage low detection */
#define RTC_VL_CLR _IO('p', 0x14) /* Clear voltage low information */
--
2.26.2


2020-05-05 20:15:44

by Alexandre Belloni

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Subject: [PATCH 2/5] rtc: pcf2127: let the core handle rtc range

Let the core handle offsetting and windowing the RTC range.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-pcf2127.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 4e50d6768f13..136709baaa88 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -137,8 +137,7 @@ static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
- if (tm->tm_year < 70)
- tm->tm_year += 100; /* assume we are in 1970...2069 */
+ tm->tm_year += 100;

dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
@@ -172,7 +171,7 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
buf[i++] = bin2bcd(tm->tm_mon + 1);

/* year */
- buf[i++] = bin2bcd(tm->tm_year % 100);
+ buf[i++] = bin2bcd(tm->tm_year - 100);

/* write register's data */
err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
@@ -433,6 +432,9 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
return PTR_ERR(pcf2127->rtc);

pcf2127->rtc->ops = &pcf2127_rtc_ops;
+ pcf2127->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
+ pcf2127->rtc->range_max = RTC_TIMESTAMP_END_2099;
+ pcf2127->rtc->set_start_time = true; /* Sets actual start to 1970 */

pcf2127->wdd.parent = dev;
pcf2127->wdd.info = &pcf2127_wdt_info;
--
2.26.2

2020-05-05 20:16:32

by Alexandre Belloni

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Subject: [PATCH 4/5] rtc: pcf2127: set regmap max_register

Set regmap max_register to ease debugging and enforce the register range.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-pcf2127.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 5ac996578523..039078029bd4 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -634,6 +634,7 @@ static int pcf2127_i2c_probe(struct i2c_client *client,
static const struct regmap_config config = {
.reg_bits = 8,
.val_bits = 8,
+ .max_register = 0x1d,
};

if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
@@ -701,6 +702,7 @@ static int pcf2127_spi_probe(struct spi_device *spi)
.val_bits = 8,
.read_flag_mask = 0xa0,
.write_flag_mask = 0x20,
+ .max_register = 0x1d,
};
struct regmap *regmap;

--
2.26.2

2020-05-05 20:17:50

by Alexandre Belloni

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Subject: [PATCH 5/5] rtc: pcf2127: report battery switch over

Add support for the RTC_VL_BACKUP_SWITCH flag to report battery switch over
events.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 039078029bd4..967de68e1b03 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -188,18 +188,27 @@ static int pcf2127_rtc_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
- int touser;
+ int val, touser = 0;
int ret;

switch (cmd) {
case RTC_VL_READ:
- ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
+ ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &val);
if (ret)
return ret;

- touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0;
+ if (val & PCF2127_BIT_CTRL3_BLF)
+ touser = RTC_VL_BACKUP_LOW;
+
+ if (val & PCF2127_BIT_CTRL3_BF)
+ touser |= RTC_VL_BACKUP_SWITCH;

return put_user(touser, (unsigned int __user *)arg);
+
+ case RTC_VL_CLR:
+ return regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
+ PCF2127_BIT_CTRL3_BF, 0);
+
default:
return -ENOIOCTLCMD;
}
@@ -493,7 +502,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
*/
ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
PCF2127_BIT_CTRL3_BTSE |
- PCF2127_BIT_CTRL3_BF |
PCF2127_BIT_CTRL3_BIE |
PCF2127_BIT_CTRL3_BLIE, 0);
if (ret) {
--
2.26.2

2020-05-05 20:18:12

by Alexandre Belloni

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Subject: [PATCH 3/5] rtc: pcf2127: remove unnecessary #ifdef

There is not point in setting .ioctl to NULL when CONFIG_RTC_INTF_DEV is
not defined because it would not be called anyway.

Signed-off-by: Alexandre Belloni <[email protected]>
---
drivers/rtc/rtc-pcf2127.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 136709baaa88..5ac996578523 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -184,7 +184,6 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
return 0;
}

-#ifdef CONFIG_RTC_INTF_DEV
static int pcf2127_rtc_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
@@ -205,9 +204,6 @@ static int pcf2127_rtc_ioctl(struct device *dev,
return -ENOIOCTLCMD;
}
}
-#else
-#define pcf2127_rtc_ioctl NULL
-#endif

static const struct rtc_class_ops pcf2127_rtc_ops = {
.ioctl = pcf2127_rtc_ioctl,
--
2.26.2

2020-05-05 21:32:46

by Rasmus Villemoes

[permalink] [raw]
Subject: Re: [PATCH 5/5] rtc: pcf2127: report battery switch over

On 05/05/2020 22.13, Alexandre Belloni wrote:
> Add support for the RTC_VL_BACKUP_SWITCH flag to report battery switch over
> events.
>
> Signed-off-by: Alexandre Belloni <[email protected]>
> ---
> drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index 039078029bd4..967de68e1b03 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -188,18 +188,27 @@ static int pcf2127_rtc_ioctl(struct device *dev,
> unsigned int cmd, unsigned long arg)
> {
> struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> - int touser;
> + int val, touser = 0;
> int ret;
>
> switch (cmd) {
> case RTC_VL_READ:
> - ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
> + ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &val);
> if (ret)
> return ret;
>
> - touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0;
> + if (val & PCF2127_BIT_CTRL3_BLF)
> + touser = RTC_VL_BACKUP_LOW;
> +
> + if (val & PCF2127_BIT_CTRL3_BF)
> + touser |= RTC_VL_BACKUP_SWITCH;

I think it's a bit easier to read if you use |= in both cases.

Re patch 3, one saves a little .text by eliding the ioctl function when,
as you say, it cannot be called anyway. No strong opinion either way, I
don't think anybody actually builds without CONFIG_RTC_INTF_DEV, but
those that do are probably the ones that care about having a tiny vmlinux.

Other than that, the series looks good to me.

Thanks,
Rasmus

2020-05-05 22:11:07

by Alexandre Belloni

[permalink] [raw]
Subject: Re: [PATCH 5/5] rtc: pcf2127: report battery switch over

On 05/05/2020 23:30:18+0200, Rasmus Villemoes wrote:
> On 05/05/2020 22.13, Alexandre Belloni wrote:
> > Add support for the RTC_VL_BACKUP_SWITCH flag to report battery switch over
> > events.
> >
> > Signed-off-by: Alexandre Belloni <[email protected]>
> > ---
> > drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++----
> > 1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> > index 039078029bd4..967de68e1b03 100644
> > --- a/drivers/rtc/rtc-pcf2127.c
> > +++ b/drivers/rtc/rtc-pcf2127.c
> > @@ -188,18 +188,27 @@ static int pcf2127_rtc_ioctl(struct device *dev,
> > unsigned int cmd, unsigned long arg)
> > {
> > struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> > - int touser;
> > + int val, touser = 0;
> > int ret;
> >
> > switch (cmd) {
> > case RTC_VL_READ:
> > - ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser);
> > + ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &val);
> > if (ret)
> > return ret;
> >
> > - touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0;
> > + if (val & PCF2127_BIT_CTRL3_BLF)
> > + touser = RTC_VL_BACKUP_LOW;
> > +
> > + if (val & PCF2127_BIT_CTRL3_BF)
> > + touser |= RTC_VL_BACKUP_SWITCH;
>
> I think it's a bit easier to read if you use |= in both cases.
>
> Re patch 3, one saves a little .text by eliding the ioctl function when,
> as you say, it cannot be called anyway. No strong opinion either way, I
> don't think anybody actually builds without CONFIG_RTC_INTF_DEV, but
> those that do are probably the ones that care about having a tiny vmlinux.
>

Honestly, I don't think it is worth doing that. On armv7, this only
removes 248 bytes. Also, compiling without CONFIG_RTC_INTF_DEV simply
makes the RTC unusable. There are no tools actually using the sysfs
interface instead of the char device interface. I prefer keeping
CONFIG_RTC_INTF_DEV private to the core.

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