On Thu, Aug 28, 2014 at 05:10:25PM +0100, Mark Rutland wrote: > On Thu, Aug 28, 2014 at 04:51:57PM +0100, Guenter Roeck wrote: > > On Thu, Aug 28, 2014 at 01:59:15PM +0100, Mark Rutland wrote: > > > On Thu, Aug 28, 2014 at 01:42:44PM +0100, Matti Vaittinen wrote: > > > > Patch adding support for specifying trickle charger setup from device > > > > tree. Patch is based on linux-next tree. > > > > > > > > > > > > Some DS13XX devices have "trickle chargers". Introduce a device tree binding > > > > for specifying the setup and register values. > > > > > > > > Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxx> > > > > --- > > > > .../devicetree/bindings/i2c/trivial-devices.txt | 1 - > > > > .../devicetree/bindings/rtc/dallas,ds1339.txt | 19 ++++++++++ > > > > drivers/rtc/rtc-ds1307.c | 44 ++++++++++++++++++++-- > > > > 3 files changed, 59 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..9faf40e > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/rtc/dallas,ds1339.txt > > > > @@ -0,0 +1,19 @@ > > > > +* Dallas DS1339 I2C Serial Real-Time Clock > > > > + > > > > +Required properties: > > > > +- compatible: Should contain "dallas,ds1339". > > > > +- reg: I2C address for chip > > > > + > > > > +Optional properties: > > > > +- trickle_setup : Used Trickle Charger configuration, > > > > + corresponding to 5 lowest bits in trickle charger register. > > > > > The value is provided via platform data, so it is platform specific > > and presumably needs to be configurable. I did, however, not find > > a single in-kernel driver which is actually setting it. > > So this is a good question. > > I'm uncomfortable adding a field we don't understand to DT. > > Is there any publicly-available documentation for the device? > Lots ;-) http://datasheets.maximintegrated.com/en/ds/DS1307.pdf http://datasheets.maximintegrated.com/en/ds/DS1337.pdf http://datasheets.maximintegrated.com/en/ds/DS1338.pdf http://datasheets.maximintegrated.com/en/ds/DS1339.pdf http://datasheets.maximintegrated.com/en/ds/DS1340.pdf http://datasheets.maximintegrated.com/en/ds/DS1388.pdf http://datasheets.maximintegrated.com/en/ds/DS3231.pdf Code suggests that DS1339, DS1339, and DS1340 have the register. Looking into the datasheets, the configuration consists of two parts: - diode connected or not - trickle charger resistor value (250, 2000, or 4000 ohm) Given that, it seems to me that those values should be configured explicitly instead of using a binary value, and that the driver should perform the conversion from dt entry to register value. Note that the relevant bits are the lower 4 bits, not the lower 5 bits, so the above text is wrong. Guenter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
