On Thu, Jun 30, 2016 at 2:00 AM, Srinivas Pandruvada
[off-list ref] wrote:

This driver adds support for Dynamic Platform and Thermal Framework
(DPTF) Platform Power Participant device support.
This participant is responsible for exposing platform telemetry such as
platform Power, battery Information such as state of Charge, estimated
maximum sustainable power (PMax), SMART battery spec information.

This driver is implemented as a platform driver for INT3407. This driver
uses services of battery_common to read battery information and state to
avoid code duplication.
Optionally this can register with power supply class and can act as
ACPI Battery. This feature is activated only when CONFIG_ACPI_BATTERY
is not defined in the configuration

There are two types of objects in INT3407:
- Same as ACPI Battery objects: _BST and _BIX. They are read directly
using the interface from battery_common
- Specific to INT3407: These objects are read directly executing
ACPI methods in this module.
These attributes are presented via sysfs interface under the INT3407
platform device:

#ls /sys/bus/platform/devices/INT3407\:00/dptf_power/
adapter_rating_mw
charger_type
design_capacity_warning_mwh
oem_info
remaining_capacity_mwh
battery_steady_power_mw
charging_state
design_voltage_mv
platform_power_source
serial_number
capacity_granularity_1_mwh
cycle_count
last_full_charge_capacity_mwh
power_sampling_period_us  type
capacity_granularity_2_mwh
design_capacity_low_mwh
max_platform_power_mw
present_rate_mw
capacity_state
design_capacity_mwh
model_number
present_voltage_mv

ACPI methods description used in this driver:
PSOC: Platform Battery State Of Charge as a percentage.
PMAX: Maximum platform power that can be supported by the battery in mW.
PSRC: System charge source,
        0x00 = DC
        0x01 = AC
        0x02 = USB
        0x03 = Wireless Charger
ARTG: Adapter rating in mW (Maximum Adapter power) Must be 0 if no AC
        Adaptor is plugged in.
CTYP: Charger Type,
        Traditional : 0x01
        Hybrid: 0x02
        NVDC: 0x03
PBSS: Returns max sustained power for battery in milliWatts.
DPSP: Polling interval in 10ths of seconds.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---

[cut]

+
+static int dptf_power_add(struct platform_device *pdev)
+{
+       struct acpi_device *acpi_dev;
+       acpi_status status;
+       unsigned long long ptype;
+       int result;
+
+       acpi_dev = ACPI_COMPANION(&(pdev->dev));
+       if (!acpi_dev)
+               return -ENODEV;
+
+       status = acpi_evaluate_integer(acpi_dev->handle, "PTYP", NULL, &ptype);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
+
+       if (ptype != 0x11)
+               return -ENODEV;
+
+#if IS_ENABLED(CONFIG_ACPI_BATTERY)
+       result = acpi_battery_common_add(acpi_dev, false);
+#else
+       result = acpi_battery_common_add(acpi_dev, true);
+#endif

You could write that as

    result = acpi_battery_common_add(acpi_dev,
!IS_ENABLED(CONFIG_ACPI_BATTERY));

However, I would always pass false as the second argument here.  At
least that would make the behavior more consistent and predictable
across different configurations.

And if that is done, the [5/5] can be improved slightly.