On 22/04/2016 at 14:32:32 -0500, Rob Herring wrote : > On Wed, Apr 20, 2016 at 01:07:49PM +0200, Jeppe Ledet-Pedersen wrote: > > This patch adds support for the Cypress Semiconductor FM33256B processor > > companion. The device contains a 256 kbit FRAM, an RTC, a supply voltage > > monitor, and a watchdog timer. > > > > Signed-off-by: Jeppe Ledet-Pedersen <j...@gomspace.com> > > --- > > Documentation/devicetree/bindings/mfd/fm33256b.txt | 30 ++ > > MAINTAINERS | 6 + > > drivers/mfd/Kconfig | 16 + > > drivers/mfd/Makefile | 1 + > > drivers/mfd/fm33256b.c | 488 > > +++++++++++++++++++++ > > include/linux/mfd/fm33256b.h | 76 ++++ > > 6 files changed, 617 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/mfd/fm33256b.txt > > create mode 100644 drivers/mfd/fm33256b.c > > create mode 100644 include/linux/mfd/fm33256b.h > > > > diff --git a/Documentation/devicetree/bindings/mfd/fm33256b.txt > > b/Documentation/devicetree/bindings/mfd/fm33256b.txt > > new file mode 100644 > > index 0000000..6591c94 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mfd/fm33256b.txt > > @@ -0,0 +1,30 @@ > > +Device-tree bindings for Cypress Semiconductor FM33256B Processor Companion > > +--------------------------------------------------------------------------- > > + > > +Required properties: > > +- compatible: must be "cypress,fm33256b". > > +- reg: SPI chip select > > +- spi-max-frequency: Max SPI frequency to use (< 16000000) > > + > > +Optional properties: > > +- cypress,charge-enabled: enable trickle charger > > What does the driver do if charging is disabled? Would using 'status = > "disabled"' be any different? >
Good catch, I didn't look at this patch but it includes a lot of code that should be going to the RTC driver. If trickle charging is not enabled, I guess the RTC will not charge its backup battery. > > +- cypress,charge-fast: enable fast (1 mA) charging > > What does fast mean? > > I think it is time for a common binding here. There's all sorts of > variations on setting the charge current in bindings. Add something like > "charge-current-microamp" in power_supply.txt and use it here. Then > 1000uA implies "fast charge". Well, this is not a power supply, it is an RTC. I think both properties should got to the RTC subdevice and be parsed in the RTC driver. Note that for trickle charging, we currently have the following properties: - trickle-resistor-ohms - trickle-diode-disable - abracon,tc-diode - abracon,tc-resistor abracon,tc-resistor can be replaced by trickle-resistor-ohms, I'll make a patch but abracon,tc-diode allows to select a diode type (and in particular a voltage drop). I think we could add a trickle-current-microamp like you suggested and trickle-diode-disable can be reused. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
