[PATCH v2] rtc: ds1307: add trickle charger device tree binding

From: Matti Vaittinen
Date: Fri Aug 29 2014 - 06:25:23 EST


Second version of the patch delta to previous:
- fixed the property fetching
- removed the trickle register property
- removed underscore from setup value property name
- added higher level meaning of setup value for ds1339 in documentation.



Some DS13XX devices have "trickle chargers". Introduce a device tree binding
for specifying the trickle charger setup value.

Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxx>
---
.../devicetree/bindings/i2c/trivial-devices.txt | 1 -
.../devicetree/bindings/rtc/dallas,ds1339.txt | 24 ++++++++++++++++++++++
drivers/rtc/rtc-ds1307.c | 23 +++++++++++++++++----
3 files changed, 43 insertions(+), 5 deletions(-)
create mode 100644 Documentation/devicetree/bindings/rtc/dallas,ds1339.txt

diff --git a/Documentation/devicetree/bindings/i2c/trivial-devices.txt b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
index 6af570e..e9206a4 100644
--- a/Documentation/devicetree/bindings/i2c/trivial-devices.txt
+++ b/Documentation/devicetree/bindings/i2c/trivial-devices.txt
@@ -35,7 +35,6 @@ catalyst,24c32 i2c serial eeprom
cirrus,cs42l51 Cirrus Logic CS42L51 audio codec
dallas,ds1307 64 x 8, Serial, I2C Real-Time Clock
dallas,ds1338 I2C RTC with 56-Byte NV RAM
-dallas,ds1339 I2C Serial Real-Time Clock
dallas,ds1340 I2C RTC with Trickle Charger
dallas,ds1374 I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output
dallas,ds1631 High-Precision Digital Thermometer
diff --git a/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt b/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt
new file mode 100644
index 0000000..07214d0
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt
@@ -0,0 +1,24 @@
+* Dallas DS1339 I2C Serial Real-Time Clock
+
+Required properties:
+- compatible: Should contain "dallas,ds1339".
+- reg: I2C address for chip
+
+Optional properties:
+- trickle : Used Trickle Charger configuration,
+ corresponding to 4 lowest bits in trickle charger register.
+ Following values are specified:
+ 0x5 => No diode, 250 ohm
+ 0x9 => Diode, 250 ohm
+ 0x6 => No diode, 2k ohm
+ 0xa => Diode, 2k ohm
+ 0x7 => No diode, 4k ohm
+ 0xb => Diode, 4k ohm
+Example:
+ ds1339: rtc@68 {
+ compatible = "dallas,ds1339";
+ trickle = <0x5>;
+ reg = <0x68>;
+ };
+
+
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index f03d5ba..cb2364e 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -126,9 +126,10 @@ struct chip_desc {
u16 nvram_offset;
u16 nvram_size;
u16 trickle_charger_reg;
+ u8 trickle_charger_setup;
};

-static const struct chip_desc chips[last_ds_type] = {
+static struct chip_desc chips[last_ds_type] = {
[ds_1307] = {
.nvram_offset = 8,
.nvram_size = 56,
@@ -833,15 +834,17 @@ ds1307_nvram_write(struct file *filp, struct kobject *kobj,
return count;
}

+
/*----------------------------------------------------------------------*/

+
static int ds1307_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds1307 *ds1307;
int err = -ENODEV;
int tmp;
- const struct chip_desc *chip = &chips[id->driver_data];
+ struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
bool want_irq = false;
unsigned char *buf;
@@ -852,6 +855,7 @@ static int ds1307_probe(struct i2c_client *client,
[ds_3231] = DS3231_BIT_BBSQW,
};
const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
+ uint32_t setup = 0;

if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
@@ -866,9 +870,20 @@ static int ds1307_probe(struct i2c_client *client,
ds1307->client = client;
ds1307->type = id->driver_data;

- if (pdata && pdata->trickle_charger_setup && chip->trickle_charger_reg)
+ if (!pdata && client->dev.of_node) {
+ of_property_read_u32(client->dev.of_node, "trickle" , &setup);
+ chip->trickle_charger_setup = setup;
+ } else if (pdata && pdata->trickle_charger_setup)
+ chip->trickle_charger_setup = pdata->trickle_charger_setup;
+
+ if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
+ dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
+ DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
+ chip->trickle_charger_reg);
i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
- DS13XX_TRICKLE_CHARGER_MAGIC | pdata->trickle_charger_setup);
+ DS13XX_TRICKLE_CHARGER_MAGIC |
+ chip->trickle_charger_setup);
+ }

buf = ds1307->regs;
if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
--
1.8.3.1
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