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rtc: pcf2127: adapt time/date registers write sequence for PCF2131

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The sequence for updating the time/date registers is slightly
different between PCF2127/29 and PCF2131.

For PCF2127/29, during write operations, the time counting
circuits (memory locations 03h through 09h) are automatically blocked.

For PCF2131, time/date registers write access requires setting the
STOP bit and sending the clear prescaler instruction (CPR). STOP then
needs to be released once write operation is completed.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-14-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Hugo Villeneuve 2023-06-22 10:57:56 -04:00 committed by Alexandre Belloni
parent e1849b8fcd
commit 3d715ebaf0
1 changed files with 34 additions and 1 deletions
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35
drivers/rtc/rtc-pcf2127.c
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@ -33,6 +33,7 @@
#define PCF2127_REG_CTRL1 0x00
#define PCF2127_BIT_CTRL1_POR_OVRD BIT(3)
#define PCF2127_BIT_CTRL1_TSF1 BIT(4)
#define PCF2127_BIT_CTRL1_STOP BIT(5)
/* Control register 2 */
#define PCF2127_REG_CTRL2 0x01
#define PCF2127_BIT_CTRL2_AIE BIT(1)
@ -280,13 +281,45 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
/* year */
buf[i++] = bin2bcd(tm->tm_year - 100);
/* write register's data */
/* Write access to time registers:
* PCF2127/29: no special action required.
* PCF2131: requires setting the STOP and CPR bits. STOP bit needs to
* be cleared after time registers are updated.
*/
if (pcf2127->cfg->type == PCF2131) {
err = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
PCF2127_BIT_CTRL1_STOP,
PCF2127_BIT_CTRL1_STOP);
if (err) {
dev_dbg(dev, "setting STOP bit failed\n");
return err;
}
err = regmap_write(pcf2127->regmap, PCF2131_REG_SR_RESET,
PCF2131_SR_RESET_CPR_CMD);
if (err) {
dev_dbg(dev, "sending CPR cmd failed\n");
return err;
}
}
/* write time register's data */
err = regmap_bulk_write(pcf2127->regmap, pcf2127->cfg->reg_time_base, buf, i);
if (err) {
dev_dbg(dev, "%s: err=%d", __func__, err);
return err;
}
if (pcf2127->cfg->type == PCF2131) {
/* Clear STOP bit (PCF2131 only) after write is completed. */
err = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL1,
PCF2127_BIT_CTRL1_STOP, 0);
if (err) {
dev_dbg(dev, "clearing STOP bit failed\n");
return err;
}
}
return 0;
}