Re: mfd: Implement devicetree support for AB8500 Btemp

On Monday 10 September 2012 07:31 PM, Arnd Bergmann wrote:

On Monday 10 September 2012, Rajanikanth HV wrote:

...

+supplied-to:

•   This is a logical binding w.r.t power supply event change
  

•   across energy-management-module drivers where in the
  

•   runtime battery properties are shared along with uevent
  

•   notification.
  

•   ref: di->btemp_psy.external_power_changed =
  

•           ab8500_btemp_external_power_changed;
  

•           ab8500_btemp.c
  

•   Need for this property:
  

•           btemp, fg and charger updates power-supply properties
  

•           based on the events listed above.
  

•           Event handler invokes power supply change notifier
  

•           which in-turn invokes registered power supply class call-back
  

•           based on the 'supplied_to' string.
  

•           ref:
  

•           power_supply_changed_work(..) ./drivers/power/power_supply_core.c
  

•   example:
  

•   ab8500-btemp {
  

•           /* Other enery management module */
  

•           supplied-to = "ab8500_chargalg", "ab8500_fg";
  

•           num_supplicants = <2>;
  

•   };
  

This looks like you're doing things the opposite way from everyone else. Normally, each device uses phandles to refer to other objects it depends on (gpio lines, regulators, clocks, interrupts, ...), rather than listing things that depend on it.

Can you turn this around to be more like the others?

We discussed about this on : "13 July 2012 17:05", pasting from that mail thread. ============================

...

+Supplied-to:

• This shall be power supply class dependency where in the
  

runtime battery

...

• properties will be shared across fuel guage and charging
  

algorithm driver.

I probably don't understand enough of this, but shouldn't the other

devices

that are supplied by this have a reference to this node rather than doing it this way around? Why use strings here instead of phandles?

This is a logical binding w.r.t power supply event change across energy-management-module drivers where in runtime battery properties are shared along with uevent notification. ref: di->btemp_psy.external_power_ changed = ab8500_btemp_external_power_changed; ref: ab8500_btemp.c

Need for this property: btemp, fg and charger updates power-supply properties based on the events listed above. Event handler invokes power supply change notifier which in-turn invokes registered power supply class call-back based on the 'supplied_to' string. ref: power_supply_changed_work(..) ./drivers/power/power_supply_core.c

In this case how to approach through phandle? ============================

Note also that device tree identifiers should use '-' as a word separator, not '_', and that a binding document should specify the exact set of possible values. If the properties contain strings, please list every valid string.

...

•           thermister-internal-to-battery = <1>;
  

•           li_ion_9100_battery = <0>;
  

Boolean properties should be empty when enabled and not present when disabled. In this example, one would just write

thermister-internal-to-battery;

Arnd