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Subject[PATCH 1/2] rtc: pcf8523: Make DSM for battery switch-over configurable from DT
Date
From: Miguel Borges de Freitas <miguelborgesdefreitas@gmail.com>

Signed-off-by: Miguel Borges de Freitas <miguelborgesdefreitas@gmail.com>
---
Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt | 7 ++++++-
Documentation/devicetree/bindings/rtc/rtc.yaml | 7 +++++++
drivers/rtc/rtc-pcf8523.c | 13 ++++++++++---
3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt
index 0b1080c..f715a8f 100644
--- a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt
+++ b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt
@@ -4,10 +4,14 @@ Required properties:
- compatible: Should contain "nxp,pcf8523".
- reg: I2C address for chip.

-Optional property:
+Optional properties:
- quartz-load-femtofarads: The capacitive load of the quartz(x-tal),
expressed in femto Farad (fF). Valid values are 7000 and 12500.
Default value (if no value is specified) is 12500fF.
+- pm-enable-dsm: battery switch-over function is enabled in direct
+ switching mode. The power failure condition happens when VDD < VBAT,
+ without requiring VDD to drop below Vth(sw)bat.
+ Default value (if not provided) is the standard mode.

Example:

@@ -15,4 +19,5 @@ pcf8523: rtc@68 {
compatible = "nxp,pcf8523";
reg = <0x68>;
quartz-load-femtofarads = <7000>;
+ pm-enable-dsm;
};
diff --git a/Documentation/devicetree/bindings/rtc/rtc.yaml b/Documentation/devicetree/bindings/rtc/rtc.yaml
index ee237b2..a0048f4 100644
--- a/Documentation/devicetree/bindings/rtc/rtc.yaml
+++ b/Documentation/devicetree/bindings/rtc/rtc.yaml
@@ -47,4 +47,11 @@ properties:
description:
Enables wake up of host system on alarm.

+ pm-enable-dsm:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description:
+ Enables the battery switch-over function in direct switching
+ mode. Should be set in systems where VDD is higher than VBAT
+ at all times.
+
...
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 47e0f41..0c08f91 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -122,7 +122,7 @@ static int pcf8523_load_capacitance(struct i2c_client *client)
return err;
}

-static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
+static int pcf8523_set_pm(struct i2c_client *client)
{
u8 value;
int err;
@@ -131,7 +131,10 @@ static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
if (err < 0)
return err;

- value = (value & ~REG_CONTROL3_PM_MASK) | pm;
+ if (of_property_read_bool(client->dev.of_node, "pm-enable-dsm"))
+ value = (value & ~REG_CONTROL3_PM_MASK) | REG_CONTROL3_PM_DSM;
+ else
+ value = (value & ~REG_CONTROL3_PM_MASK) | 0;

err = pcf8523_write(client, REG_CONTROL3, value);
if (err < 0)
@@ -173,6 +176,10 @@ static int pcf8523_start_rtc(struct i2c_client *client)
if (err < 0)
return err;

+ err = pcf8523_set_pm(client);
+ if (err < 0)
+ return err;
+
return 0;
}

@@ -352,7 +359,7 @@ static int pcf8523_probe(struct i2c_client *client,
dev_warn(&client->dev, "failed to set xtal load capacitance: %d",
err);

- err = pcf8523_set_pm(client, 0);
+ err = pcf8523_set_pm(client);
if (err < 0)
return err;

--
1.8.3.1
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