Re: [PATCH v3 02/14] rtc: pcf2127: adapt for time/date registers at any offset

From: Hugo Villeneuve
Date: Mon Jan 23 2023 - 10:55:06 EST

On Fri, 20 Jan 2023 19:47:53 +0100
Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> wrote:

> On 15/12/2022 10:02:03-0500, Hugo Villeneuve wrote:
> > From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> >
> > This will simplify the implementation of new variants into this driver.
> >
> > Some variants (PCF2131) have a 100th seconds register. This register is
> > currently not supported in this driver.
> >
> > Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
> > ---
> > drivers/rtc/rtc-pcf2127.c | 68 ++++++++++++++++++++++-----------------
> > 1 file changed, 39 insertions(+), 29 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> > index b9a5d47a439f..fb0caacaabee 100644
> > --- a/drivers/rtc/rtc-pcf2127.c
> > +++ b/drivers/rtc/rtc-pcf2127.c
> > @@ -44,14 +44,17 @@
> > #define PCF2127_BIT_CTRL3_BF BIT(3)
> > #define PCF2127_BIT_CTRL3_BTSE BIT(4)
> > /* Time and date registers */
> > -#define PCF2127_REG_SC 0x03
> > +#define PCF2127_REG_TIME_DATE_BASE 0x03
> > +/* Time and date registers offsets (starting from base register) */
> > +#define PCF2127_OFFSET_TD_SC 0
> > +#define PCF2127_OFFSET_TD_MN 1
> > +#define PCF2127_OFFSET_TD_HR 2
> > +#define PCF2127_OFFSET_TD_DM 3
> > +#define PCF2127_OFFSET_TD_DW 4
> > +#define PCF2127_OFFSET_TD_MO 5
> > +#define PCF2127_OFFSET_TD_YR 6
>
> Same comment as for the alarms, I would simply remove the defines as
> they don't really carry any useful information.

Note that if I remove them, the patch for pcf2127_rtc_read_time() would look like this:

/* Clock integrity is not guaranteed when OSF flag is set. */
- if (buf[PCF2127_REG_SC] & PCF2127_BIT_SC_OSF) {
+ if (buf[0] & PCF2127_BIT_SC_OSF) {
...
- __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
- buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
- buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
- buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
-
- tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
- tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
- tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
- tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
- 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]);
+ __func__, ctrl3, buf[0],
+ buf[1], buf[2],
+ buf[3], buf[4],
+ buf[5], buf[PCF2127_OFFSET_TD_YR]);
+
+ tm->tm_sec = bcd2bin(buf[0] & 0x7F);
+ tm->tm_min = bcd2bin(buf[1] & 0x7F);
+ tm->tm_hour = bcd2bin(buf[2] & 0x3F); /* rtc hr 0-23 */
+ tm->tm_mday = bcd2bin(buf[3] & 0x3F);
+ tm->tm_wday = buf[4] & 0x07;
+ tm->tm_mon = bcd2bin(buf[5] & 0x1F) - 1; /* rtc mn 1-12 */
+ tm->tm_year = bcd2bin(buf[6]);

Do you still want to remove the defines then?


> > +/* Time and date registers bits */
> > #define PCF2127_BIT_SC_OSF BIT(7)
> > -#define PCF2127_REG_MN 0x04
> > -#define PCF2127_REG_HR 0x05
> > -#define PCF2127_REG_DM 0x06
> > -#define PCF2127_REG_DW 0x07
> > -#define PCF2127_REG_MO 0x08
> > -#define PCF2127_REG_YR 0x09
> > /* Alarm registers */
> > #define PCF2127_REG_ALARM_SC 0x0A
> > #define PCF2127_REG_ALARM_MN 0x0B
> > @@ -106,6 +109,7 @@ struct pcf21xx_config {
> > int max_register;
> > unsigned int has_nvmem:1;
> > unsigned int has_bit_wd_ctl_cd0:1;
> > + u8 regs_td_base; /* Time/data base registers. */
> > };
> >
> > struct pcf2127 {
> > @@ -125,27 +129,31 @@ struct pcf2127 {
> > static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
> > {
> > struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> > - unsigned char buf[10];
> > + unsigned char buf[7];
> > + unsigned int ctrl3;
> > int ret;
> >
> > /*
> > * Avoid reading CTRL2 register as it causes WD_VAL register
> > * value to reset to 0 which means watchdog is stopped.
> > */
> > - ret = regmap_bulk_read(pcf2127->regmap, PCF2127_REG_CTRL3,
> > - (buf + PCF2127_REG_CTRL3),
> > - ARRAY_SIZE(buf) - PCF2127_REG_CTRL3);
> > - if (ret) {
> > - dev_err(dev, "%s: read error\n", __func__);
> > + ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &ctrl3);
> > + if (ret)
> > return ret;
> > - }
> >
> > - if (buf[PCF2127_REG_CTRL3] & PCF2127_BIT_CTRL3_BLF)
> > + if (ctrl3 & PCF2127_BIT_CTRL3_BLF)
> > dev_info(dev,
> > "low voltage detected, check/replace RTC battery.\n");
> >
> > + ret = regmap_bulk_read(pcf2127->regmap, pcf2127->cfg->regs_td_base,
> > + buf, sizeof(buf));
> > + if (ret) {
> > + dev_err(dev, "%s: read error\n", __func__);
> > + return ret;
> > + }
> > +
> > /* Clock integrity is not guaranteed when OSF flag is set. */
> > - if (buf[PCF2127_REG_SC] & PCF2127_BIT_SC_OSF) {
> > + if (buf[PCF2127_OFFSET_TD_SC] & PCF2127_BIT_SC_OSF) {
> > /*
> > * no need clear the flag here,
> > * it will be cleared once the new date is saved
> > @@ -158,18 +166,18 @@ static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
> > dev_dbg(dev,
> > "%s: raw data is cr3=%02x, sec=%02x, min=%02x, hr=%02x, "
> > "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
> > - __func__, buf[PCF2127_REG_CTRL3], buf[PCF2127_REG_SC],
> > - buf[PCF2127_REG_MN], buf[PCF2127_REG_HR],
> > - buf[PCF2127_REG_DM], buf[PCF2127_REG_DW],
> > - buf[PCF2127_REG_MO], buf[PCF2127_REG_YR]);
> > -
> > - tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
> > - tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
> > - tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
> > - tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
> > - 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]);
> > + __func__, ctrl3, buf[PCF2127_OFFSET_TD_SC],
> > + buf[PCF2127_OFFSET_TD_MN], buf[PCF2127_OFFSET_TD_HR],
> > + buf[PCF2127_OFFSET_TD_DM], buf[PCF2127_OFFSET_TD_DW],
> > + buf[PCF2127_OFFSET_TD_MO], buf[PCF2127_OFFSET_TD_YR]);
> > +
> > + tm->tm_sec = bcd2bin(buf[PCF2127_OFFSET_TD_SC] & 0x7F);
> > + tm->tm_min = bcd2bin(buf[PCF2127_OFFSET_TD_MN] & 0x7F);
> > + tm->tm_hour = bcd2bin(buf[PCF2127_OFFSET_TD_HR] & 0x3F); /* rtc hr 0-23 */
>
> You can drop the comment

Done

>
> > + tm->tm_mday = bcd2bin(buf[PCF2127_OFFSET_TD_DM] & 0x3F);
> > + tm->tm_wday = buf[PCF2127_OFFSET_TD_DW] & 0x07;
> > + tm->tm_mon = bcd2bin(buf[PCF2127_OFFSET_TD_MO] & 0x1F) - 1; /* rtc mn 1-12 */
>
> This comment too.

Done

>
> > + tm->tm_year = bcd2bin(buf[PCF2127_OFFSET_TD_YR]);
> > tm->tm_year += 100;
> >
> > dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
> > @@ -207,7 +215,7 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
> > buf[i++] = bin2bcd(tm->tm_year - 100);
> >
> > /* write register's data */
> > - err = regmap_bulk_write(pcf2127->regmap, PCF2127_REG_SC, buf, i);
> > + err = regmap_bulk_write(pcf2127->regmap, pcf2127->cfg->regs_td_base, buf, i);
> > if (err) {
> > dev_err(dev,
> > "%s: err=%d", __func__, err);
> > @@ -650,11 +658,13 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
> > .max_register = 0x1d,
> > .has_nvmem = 1,
> > .has_bit_wd_ctl_cd0 = 1,
> > + .regs_td_base = PCF2127_REG_TIME_DATE_BASE,
> > },
> > [PCF2129] = {
> > .max_register = 0x19,
> > .has_nvmem = 0,
> > .has_bit_wd_ctl_cd0 = 0,
> > + .regs_td_base = PCF2127_REG_TIME_DATE_BASE,
> > },
> > };
> >
> > --
> > 2.30.2
> >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>


--
Hugo Villeneuve <hugo@xxxxxxxxxxx>