linux-kernel - [PATCH v1] rtc: pcf2127: configurable power management function

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Message-Id: <20240408054926.3994-1-markus.burri@mt.com>
Date: Mon,  8 Apr 2024 07:49:26 +0200
From: Markus Burri <markus.burri@...com>
To: linux-kernel@...r.kernel.org
Cc: Markus Burri <markus.burri@...com>,
	Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	linux-rtc@...r.kernel.org,
	devicetree@...r.kernel.org
Subject: [PATCH v1] rtc: pcf2127: configurable power management function

In the PCF2131 power management the battery switch-over function is
disabled by default.
After a power cycle the rtc clock is wrong because of that.
Add a device-tree property to configure the power management function
and enable battery switch-over.

Signed-off-by: Markus Burri <markus.burri@...com>
---
 .../devicetree/bindings/rtc/nxp,pcf2127.yaml  |  3 +++
 drivers/rtc/rtc-pcf2127.c                     | 22 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf2127.yaml b/Documentation/devicetree/bindings/rtc/nxp,pcf2127.yaml
index 2d9fe5a75b06..5ce0ca6dcedc 100644
--- a/Documentation/devicetree/bindings/rtc/nxp,pcf2127.yaml
+++ b/Documentation/devicetree/bindings/rtc/nxp,pcf2127.yaml
@@ -30,6 +30,9 @@ properties:
 
   reset-source: true
 
+  pwrmng-function:
+    description: Set power management function for PCF2131
+
 required:
   - compatible
   - reg
diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 9c04c4e1a49c..30d56538c11e 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -48,6 +48,7 @@
 #define PCF2127_BIT_CTRL3_BLF			BIT(2)
 #define PCF2127_BIT_CTRL3_BF			BIT(3)
 #define PCF2127_BIT_CTRL3_BTSE			BIT(4)
+#define PCF2131_BIT_CTRL3_PWRMNG_MASK   GENMASK(7, 5)
 /* Time and date registers */
 #define PCF2127_REG_TIME_BASE		0x03
 #define PCF2127_BIT_SC_OSF			BIT(7)
@@ -187,6 +188,7 @@ struct pcf21xx_config {
 	unsigned int has_bit_wd_ctl_cd0:1;
 	unsigned int wd_val_reg_readable:1; /* If watchdog value register can be read. */
 	unsigned int has_int_a_b:1; /* PCF2131 supports two interrupt outputs. */
+	unsigned int has_pwrmng:1; /* PCF2131 supports power management. */
 	u8 reg_time_base; /* Time/date base register. */
 	u8 regs_alarm_base; /* Alarm function base registers. */
 	u8 reg_wd_ctl; /* Watchdog control register. */
@@ -926,6 +928,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
 		.has_bit_wd_ctl_cd0 = 1,
 		.wd_val_reg_readable = 1,
 		.has_int_a_b = 0,
+		.has_pwrmng = 0,
 		.reg_time_base = PCF2127_REG_TIME_BASE,
 		.regs_alarm_base = PCF2127_REG_ALARM_BASE,
 		.reg_wd_ctl = PCF2127_REG_WD_CTL,
@@ -954,6 +957,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
 		.has_bit_wd_ctl_cd0 = 0,
 		.wd_val_reg_readable = 1,
 		.has_int_a_b = 0,
+		.has_pwrmng = 0,
 		.reg_time_base = PCF2127_REG_TIME_BASE,
 		.regs_alarm_base = PCF2127_REG_ALARM_BASE,
 		.reg_wd_ctl = PCF2127_REG_WD_CTL,
@@ -982,6 +986,7 @@ static struct pcf21xx_config pcf21xx_cfg[] = {
 		.has_bit_wd_ctl_cd0 = 0,
 		.wd_val_reg_readable = 0,
 		.has_int_a_b = 1,
+		.has_pwrmng = 1,
 		.reg_time_base = PCF2131_REG_TIME_BASE,
 		.regs_alarm_base = PCF2131_REG_ALARM_BASE,
 		.reg_wd_ctl = PCF2131_REG_WD_CTL,
@@ -1241,6 +1246,23 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 		return ret;
 	}
 
+	if (pcf2127->cfg->has_pwrmng) {
+		uint32_t pwrmng;
+		if (!device_property_read_u32(dev, "pwrmng-function", &pwrmng)) {
+			if (!FIELD_FIT(PCF2131_BIT_CTRL3_PWRMNG_MASK, pwrmng)) {
+				dev_err(dev, "invalid power management function\n");
+				return ret;
+			}
+			ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_CTRL3,
+						 PCF2131_BIT_CTRL3_PWRMNG_MASK,
+						 FIELD_PREP(PCF2131_BIT_CTRL3_PWRMNG_MASK, pwrmng));
+			if (ret) {
+				dev_err(dev, "%s: pwrmng (ctrl3) failed\n",	__func__);
+				return ret;
+			}
+		}
+	}
+
 	/*
 	 * Enable timestamp functions 1 to 4.
 	 */
-- 
2.39.2