Introduce a device tree binding for specifying the trickle charger
configuration for ds1374. This is based on the code for ds13390.
Signed-off-by: Moritz Fischer <mdf@xxxxxxxxxx>
---
.../devicetree/bindings/rtc/dallas,ds1374.txt | 18 ++++++++
drivers/rtc/rtc-ds1374.c | 54 ++++++++++++++++++++++
2 files changed, 72 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rtc/dallas,ds1374.txt
diff --git a/Documentation/devicetree/bindings/rtc/dallas,ds1374.txt b/Documentation/devicetree/bindings/rtc/dallas,ds1374.txt
new file mode 100644
index 0000000..4cf5bd7
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/dallas,ds1374.txt
@@ -0,0 +1,18 @@
+* Dallas DS1374 I2C Real-Time Clock / WDT
+
+Required properties:
+- compatible: Should contain "dallas,ds1374".
+- reg: I2C address for chip
+
+Optional properties:
+- trickle-resistor-ohms : Selected resistor for trickle charger
+ Values usable for ds1374 are 250, 2000, 4000
+ Should be given if trickle charger should be enabled
+- trickle-diode-disable : Do not use internal trickle charger diode
+ Should be given if internal trickle charger diode should be disabled
+Example:
+ ds1374: rtc@0 {
+ compatible = "dallas,ds1374";
+ trickle-resistor-ohms = <250>;
+ reg = <0>;
+ };
diff --git a/drivers/rtc/rtc-ds1374.c b/drivers/rtc/rtc-ds1374.c
index 4cd115e..873475d 100644
--- a/drivers/rtc/rtc-ds1374.c
+++ b/drivers/rtc/rtc-ds1374.c
@@ -53,6 +53,13 @@
#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
#define DS1374_REG_TCR 0x09 /* Trickle Charge */
+#define DS1374_TRICKLE_CHARGER_ENABLE 0xA0
+#define DS1374_TRICKLE_CHARGER_250_OHM 0x01
+#define DS1374_TRICKLE_CHARGER_2K_OHM 0x02
+#define DS1374_TRICKLE_CHARGER_4K_OHM 0x03
+#define DS1374_TRICKLE_CHARGER_NO_DIODE 0x04
+#define DS1374_TRICKLE_CHARGER_DIODE 0x08
+
static const struct i2c_device_id ds1374_id[] = {
{ "ds1374", 0 },
{ }
@@ -597,6 +604,49 @@ static struct notifier_block ds1374_wdt_notifier = {
};
#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
+
+static int ds1374_trickle_of_init(struct i2c_client *client)
+{
+ u32 ohms = 0;
+ u8 value;
+ int ret;
+
+ if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms",
+ &ohms))
+ return 0;
+
+ /* Enable charger */
+ value = DS1374_TRICKLE_CHARGER_ENABLE;
+ if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
+ value |= DS1374_TRICKLE_CHARGER_NO_DIODE;
+ else
+ value |= DS1374_TRICKLE_CHARGER_DIODE;
+
+ /* Resistor select */
+ switch (ohms) {
+ case 250:
+ value |= DS1374_TRICKLE_CHARGER_250_OHM;
+ break;
+ case 2000:
+ value |= DS1374_TRICKLE_CHARGER_2K_OHM;
+ break;
+ case 4000:
+ value |= DS1374_TRICKLE_CHARGER_4K_OHM;
+ break;
+ default:
+ dev_warn(&client->dev,
+ "Unsupported ohm value %02ux in dt\n", ohms);
+ return -EINVAL;
+ }
+ dev_dbg(&client->dev, "Trickle charge value is 0x%02x\n", value);
+
+ ret = i2c_smbus_write_byte_data(client, DS1374_REG_TCR, value);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
/*
*****************************************************************************
*
@@ -620,6 +670,10 @@ static int ds1374_probe(struct i2c_client *client,
INIT_WORK(&ds1374->work, ds1374_work);
mutex_init(&ds1374->mutex);
+ ret = ds1374_trickle_of_init(client);
+ if (ret)
+ return ret;
+
ret = ds1374_check_rtc_status(client);
if (ret)
return ret;
--
2.7.4
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