dt-bindings: power: supply: bq27xxx: Add monitored-battery documentation

[H. Nikolaus Schaller]

Hi,
I am trying to get this working on our bq27421.

But the only message I get is:

[    6.086407] bq27xxx-battery 1-0055: data memory update not supported for chip

A little research shows that this message comes from

	http://elixir.free-electrons.com/linux/v4.13-rc7/source/drivers/power/supply/bq27xxx_battery.c#L1279

So di->dm_regs is NULL.

But doing an fgrep for dm_regs shows no line of code where the pointer is set to a non-null value:

master hns$ fgrep -R dm_regs *
drivers/power/supply/bq27xxx_battery.c:	.class = (di)->dm_regs[i].subclass_id, \
drivers/power/supply/bq27xxx_battery.c:	.block = (di)->dm_regs[i].offset / BQ27XXX_DM_SZ, \
drivers/power/supply/bq27xxx_battery.c:	struct bq27xxx_dm_reg *reg = &di->dm_regs[reg_id];
drivers/power/supply/bq27xxx_battery.c:	if (!di->dm_regs) {
drivers/power/supply/bq27xxx_battery.c:	max = di->dm_regs[BQ27XXX_DM_DESIGN_ENERGY].max;
drivers/power/supply/bq27xxx_battery.c:	max = di->dm_regs[BQ27XXX_DM_DESIGN_CAPACITY].max;
drivers/power/supply/bq27xxx_battery.c:	min = di->dm_regs[BQ27XXX_DM_TERMINATE_VOLTAGE].min;
drivers/power/supply/bq27xxx_battery.c:	max = di->dm_regs[BQ27XXX_DM_TERMINATE_VOLTAGE].max;
Binary file drivers/power/supply/bq27xxx_battery.ko matches
Binary file drivers/power/supply/bq27xxx_battery.o matches
Binary file drivers/power/supply/bq27xxx_battery_i2c.ko matches
Binary file drivers/power/supply/bq27xxx_battery_i2c.o matches
include/linux/power/bq27xxx_battery.h:	struct bq27xxx_dm_reg *dm_regs;
master hns$ 

What am I doing wrong here?

BR and thanks,
Nikolaus