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Message-Id: <20250612143338.45943-1-giampiero@sferalabs.cc>
Date: Thu, 12 Jun 2025 16:33:38 +0200
From: Giampiero Baggiani <giampiero@...ralabs.cc>
To: alexandre.belloni@...tlin.com
Cc: Giampiero Baggiani <giampiero@...ralabs.cc>,
linux-rtc@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] rtc: pcf2127: add power management device properties
Added the "backup-switchover-mode" and the "battery-low-detection-set"
device properties.
Especially relevant for PCF2131 which comes with BSM and BLD disabled
by default.
If the properties are not specified the driver behaves as before, keeping
the configuration unchanged.
The "battery-low-detection-set" property solves the current issue of BLD
config lost when switching between BSMs.
The RTC_FEATURE_BACKUP_SWITCH_MODE is also set.
Signed-off-by: Giampiero Baggiani <giampiero@...ralabs.cc>
---
drivers/rtc/rtc-pcf2127.c | 206 ++++++++++++++++++++++++++++++--------
1 file changed, 163 insertions(+), 43 deletions(-)
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 31c7dca8f469..b381b31b6d20 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -182,6 +182,12 @@ struct pcf21xx_ts_config {
u8 ie_bit; /* Interrupt enable bit. */
};
+struct pcf21xx_pwrmng_config {
+ int bsm;
+ bool bld;
+ bool pfd;
+};
+
struct pcf21xx_config {
int type; /* IC variant */
int max_register;
@@ -209,6 +215,7 @@ struct pcf2127 {
bool irq_enabled;
time64_t ts[PCF2127_MAX_TS_SUPPORTED]; /* Timestamp values. */
bool ts_valid[PCF2127_MAX_TS_SUPPORTED]; /* Timestamp valid indication. */
+ bool bld_set;
};
/*
@@ -333,26 +340,130 @@ static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
return 0;
}
-static int pcf2127_param_get(struct device *dev, struct rtc_param *param)
+static int pcf2127_rtc_get_pwrmng(struct device *dev,
+ struct pcf21xx_pwrmng_config *cfg)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
- u32 value;
+ unsigned int value;
+ int ret;
+
+ ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &value);
+ if (ret < 0)
+ return ret;
+
+ value = FIELD_GET(PCF2127_CTRL3_PM, value);
+
+ switch (value) {
+ case 0:
+ cfg->bsm = RTC_BSM_LEVEL;
+ cfg->bld = true;
+ cfg->pfd = true;
+ break;
+
+ case 1:
+ cfg->bsm = RTC_BSM_LEVEL;
+ cfg->bld = false;
+ cfg->pfd = true;
+ break;
+
+ case 2:
+ cfg->bsm = RTC_BSM_LEVEL;
+ cfg->bld = false;
+ cfg->pfd = false;
+ break;
+
+ case 3:
+ cfg->bsm = RTC_BSM_DIRECT;
+ cfg->bld = true;
+ cfg->pfd = true;
+ break;
+
+ case 4:
+ cfg->bsm = RTC_BSM_DIRECT;
+ cfg->bld = false;
+ cfg->pfd = true;
+ break;
+
+ case 5:
+ cfg->bsm = RTC_BSM_DIRECT;
+ cfg->bld = false;
+ cfg->pfd = false;
+ break;
+
+ case 6:
+ cfg->bsm = RTC_BSM_DISABLED;
+ cfg->bld = false;
+ cfg->pfd = true;
+ break;
+
+ default:
+ cfg->bsm = RTC_BSM_DISABLED;
+ cfg->bld = false;
+ cfg->pfd = false;
+ break;
+ }
+
+ return 0;
+}
+
+static int pcf2127_rtc_set_pwrmng(struct device *dev,
+ struct pcf21xx_pwrmng_config *cfg)
+{
+ struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
+ unsigned int value;
+
+ if (cfg->bld)
+ cfg->pfd = true;
+
+ switch (cfg->bsm) {
+ case RTC_BSM_LEVEL:
+ if (cfg->bld)
+ value = 0;
+ else if (cfg->pfd)
+ value = 1;
+ else
+ value = 2;
+ break;
+
+ case RTC_BSM_DIRECT:
+ if (cfg->bld)
+ value = 3;
+ else if (cfg->pfd)
+ value = 4;
+ else
+ value = 5;
+ break;
+
+ case RTC_BSM_DISABLED:
+ if (cfg->bld)
+ return -EINVAL;
+ else if (cfg->pfd)
+ value = 6;
+ else
+ value = 7;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
+ PCF2127_CTRL3_PM,
+ FIELD_PREP(PCF2127_CTRL3_PM, value));
+}
+
+static int pcf2127_param_get(struct device *dev, struct rtc_param *param)
+{
+ struct pcf21xx_pwrmng_config cfg;
int ret;
switch (param->param) {
case RTC_PARAM_BACKUP_SWITCH_MODE:
- ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &value);
+ ret = pcf2127_rtc_get_pwrmng(dev, &cfg);
if (ret < 0)
return ret;
- value = FIELD_GET(PCF2127_CTRL3_PM, value);
-
- if (value < 0x3)
- param->uvalue = RTC_BSM_LEVEL;
- else if (value < 0x6)
- param->uvalue = RTC_BSM_DIRECT;
- else
- param->uvalue = RTC_BSM_DISABLED;
+ param->uvalue = cfg.bsm;
break;
@@ -366,49 +477,23 @@ static int pcf2127_param_get(struct device *dev, struct rtc_param *param)
static int pcf2127_param_set(struct device *dev, struct rtc_param *param)
{
struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
- u8 mode = 0;
- u32 value;
+ struct pcf21xx_pwrmng_config cfg;
int ret;
switch (param->param) {
case RTC_PARAM_BACKUP_SWITCH_MODE:
- ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &value);
+ ret = pcf2127_rtc_get_pwrmng(dev, &cfg);
if (ret < 0)
return ret;
- value = FIELD_GET(PCF2127_CTRL3_PM, value);
-
- if (value > 5)
- value -= 5;
- else if (value > 2)
- value -= 3;
-
- switch (param->uvalue) {
- case RTC_BSM_LEVEL:
- break;
- case RTC_BSM_DIRECT:
- mode = 3;
- break;
- case RTC_BSM_DISABLED:
- if (value == 0)
- value = 1;
- mode = 5;
- break;
- default:
- return -EINVAL;
- }
-
- return regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
- PCF2127_CTRL3_PM,
- FIELD_PREP(PCF2127_CTRL3_PM, mode + value));
-
- break;
+ cfg.bsm = param->uvalue;
+ if (pcf2127->bld_set && cfg.bsm != RTC_BSM_DISABLED)
+ cfg.bld = true;
+ return pcf2127_rtc_set_pwrmng(dev, &cfg);
default:
return -EINVAL;
}
-
- return 0;
}
static int pcf2127_rtc_ioctl(struct device *dev,
@@ -1181,6 +1266,8 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
struct pcf2127 *pcf2127;
int ret = 0;
unsigned int val;
+ struct pcf21xx_pwrmng_config pm_cfg;
+ bool pm_cfg_write = false;
dev_dbg(dev, "%s\n", __func__);
@@ -1323,6 +1410,39 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
return ret;
}
+ ret = pcf2127_rtc_get_pwrmng(dev, &pm_cfg);
+ if (ret) {
+ dev_err(dev,
+ "%s: power management config (ctrl3) read failed\n",
+ __func__);
+ return ret;
+ }
+
+ if (!device_property_read_u32(dev, "backup-switchover-mode",
+ &pm_cfg.bsm)) {
+ pm_cfg_write = true;
+ }
+
+ pcf2127->bld_set = device_property_read_bool(dev,
+ "battery-low-detection-set");
+ if (pcf2127->bld_set) {
+ if (pm_cfg.bsm != RTC_BSM_DISABLED)
+ pm_cfg.bld = true;
+ pm_cfg_write = true;
+ }
+
+ if (pm_cfg_write) {
+ ret = pcf2127_rtc_set_pwrmng(dev, &pm_cfg);
+ if (ret) {
+ dev_err(dev,
+ "%s: power management config (ctrl3) failed\n",
+ __func__);
+ return ret;
+ }
+ }
+
+ set_bit(RTC_FEATURE_BACKUP_SWITCH_MODE, pcf2127->rtc->features);
+
/*
* Enable timestamp functions 1 to 4.
*/
--
2.39.2 (Apple Git-143)
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