Re: [PATCH v2 11/14] power: supply: bq24190_charger: Get input_current_limit from our supplier

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 28-08-17 20:07, Liam Breck wrote:
> Hi Hans, I sent too soon...
> 
> On Mon, Aug 28, 2017 at 9:04 AM, Hans de Goede <hdegoede@redhat.com> wrote:
>> Hi,
>>
>>
>> On 16-08-17 22:28, Liam Breck wrote:
>>>
>>> Hi Hans,
>>>
>>> On Tue, Aug 15, 2017 at 1:04 PM, Hans de Goede <hdegoede@redhat.com>
>>> wrote:
>>>>
>>>> On some devices the USB Type-C port power (USB PD 2.0) negotiation is
>>>> done by a separate port-controller IC, while the current limit is
>>>> controlled through another (charger) IC.
>>>>
>>>> It has been decided to model this by modelling the external Type-C
>>>> power brick (adapter/charger) as a power-supply class device which
>>>> supplies the charger-IC, with its voltage-now and current-max
>>>> representing
>>>> the negotiated voltage and max current draw.
>>>>
>>>> This commit adds support for this to the bq24190_charger driver by
>>>> calling
>>>> power_supply_set_input_current_limit_from_supplier helper if the
>>>> "input-current-limit-from-supplier" device-property is set.
>>>>
>>>> Note this replaces the functionality to get the current-limit from an
>>>> extcon device, which will be removed in a follow-up commit.
>>>>
>>>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>>>> ---
>>>> Changes in v2:
>>>> -Wait a bit before applying current-max from our supplier as
>>>> input-current-limit
>>>>    the bq24190 may still be in its power-good wait-state while our
>>>> supplier is
>>>>    done negotating current-max and if we apply the limit to early then the
>>>>    input-current-limit will be reset to 0.5A by the bq24190 after its
>>>>    power-good wait is done.
>>>> ---
>>>>    drivers/power/supply/bq24190_charger.c | 35
>>>> ++++++++++++++++++++++++++++++++++
>>>>    1 file changed, 35 insertions(+)
>>>>
>>>> diff --git a/drivers/power/supply/bq24190_charger.c
>>>> b/drivers/power/supply/bq24190_charger.c
>>>> index f13f892..6f75c8e 100644
>>>> --- a/drivers/power/supply/bq24190_charger.c
>>>> +++ b/drivers/power/supply/bq24190_charger.c
>>>> @@ -159,9 +159,11 @@ struct bq24190_dev_info {
>>>>           struct extcon_dev               *extcon;
>>>>           struct notifier_block           extcon_nb;
>>>>           struct delayed_work             extcon_work;
>>>> +       struct delayed_work             input_current_limit_work;
>>>>           char                            model_name[I2C_NAME_SIZE];
>>>>           bool                            initialized;
>>>>           bool                            irq_event;
>>>> +       bool
>>>> input_current_limit_from_supplier;
>>>>           struct mutex                    f_reg_lock;
>>>>           u8                              f_reg;
>>>>           u8                              ss_reg;
>>>> @@ -1142,6 +1144,32 @@ static int
>>>> bq24190_charger_property_is_writeable(struct power_supply *psy,
>>>>           return ret;
>>>>    }
>>>>
>>>> +static void bq24190_input_current_limit_work(struct work_struct *work)
>>>> +{
>>>> +       struct bq24190_dev_info *bdi =
>>>> +               container_of(work, struct bq24190_dev_info,
>>>> +                            input_current_limit_work.work);
>>>> +
>>>> +       power_supply_set_input_current_limit_from_supplier(bdi->charger);
>>>> +}
>>>> +
>>>> +static void bq24190_charger_external_power_changed(struct power_supply
>>>> *psy)
>>>> +{
>>>> +       struct bq24190_dev_info *bdi = power_supply_get_drvdata(psy);
>>>> +
>>>> +       /*
>>>> +        * The Power-Good detection may take up to 220ms, sometimes
>>>> +        * the external charger detection is quicker, and the bq24190
>>>> will
>>>> +        * reset to iinlim based on its own charger detection (which is
>>>> not
>>>> +        * hooked up when using external charger detection) resulting in
>>>> a
>>>> +        * too low default 500mA iinlim. Delay setting the
>>>> input-current-limit
>>>> +        * for 300ms to avoid this.
>>>> +        */
>>>> +       if (bdi->input_current_limit_from_supplier)
>>>> +               queue_delayed_work(system_wq,
>>>> &bdi->input_current_limit_work,
>>>> +                                  msecs_to_jiffies(300));
>>>> +}
>>>> +
>>>>    static enum power_supply_property bq24190_charger_properties[] = {
>>>>           POWER_SUPPLY_PROP_CHARGE_TYPE,
>>>>           POWER_SUPPLY_PROP_HEALTH,
>>>> @@ -1170,6 +1198,7 @@ static const struct power_supply_desc
>>>> bq24190_charger_desc = {
>>>>           .get_property           = bq24190_charger_get_property,
>>>>           .set_property           = bq24190_charger_set_property,
>>>>           .property_is_writeable  = bq24190_charger_property_is_writeable,
>>>> +       .external_power_changed = bq24190_charger_external_power_changed,
>>>>    };
>>>>
>>>>    /* Battery power supply property routines */
>>>> @@ -1651,6 +1680,8 @@ static int bq24190_probe(struct i2c_client *client,
>>>>           mutex_init(&bdi->f_reg_lock);
>>>>           bdi->f_reg = 0;
>>>>           bdi->ss_reg = BQ24190_REG_SS_VBUS_STAT_MASK; /* impossible state
>>>> */
>>>> +       INIT_DELAYED_WORK(&bdi->input_current_limit_work,
>>>> +                         bq24190_input_current_limit_work);
>>>>
>>>>           i2c_set_clientdata(client, bdi);
>>>>
>>>> @@ -1659,6 +1690,10 @@ static int bq24190_probe(struct i2c_client
>>>> *client,
>>>>                   return -EINVAL;
>>>>           }
>>>>
>>>> +       bdi->input_current_limit_from_supplier =
>>>> +               device_property_read_bool(dev,
>>>> +
>>>> "input-current-limit-from-supplier");
>>>> +
>>>
>>>
>>> Maybe
>>>     if (device_property_read_bool(dev,
>>> "linux,input-current-limit-from-supplier")) {
>>>          INIT_DELAYED_WORK(&bdi->input_current_limit_work,
>>>                            bq24190_input_current_limit_work);
>>>         bdi->input_current_limit_from_supplier = true; // or use a field
>>> in bdi->input_current_limit_work as the flag?
>>>      }
>>
>>
>> Done, except for making the flag a field in input_current_limit_work,
>> input_current_limit_work is of type struct delayed_work so I cannot just
>> add a field.
>>
>>> Also should document property for DT use assuming Sebastian is ok with
>>> new power_supply method.
>>
>>
>> Also done for v3 of this patch.
>>
>>> And can you rebase to my pending series in next pass? There's nothing
>>> controversial in it :-)
>>
>>
>> I've cherry-picked v3 of the patch adding the dt-binding-doc to my tree so
>> that I could add the documentation for the property on top. I will make sure
>> to rebase on top of the rest once the rest is merged by Sebastian (otherwise
>> I need to rebase after each revision of the patch-set).
> 
> If the property is linux,input-current-limit-from-supplier should it
> also be documented elsewhere in DT bindings?

linux, just means that it is Linux specific, it can still be a
per-device binding, although maybe we should make it a generic
power-supply consumer property? And at it to:

Documentation/devicetree/bindings/power/supply/power_supply.txt

Since that binding does not appear to be Linux specific, I've
gone with ti,input-current-limit-from-supplier for now and I've
documented it in the bq24190 bindings for now.

I've also added the device-tree binding maintainers to the Cc,
for the still to be send v3 of the patch-set, so lets just wait
and see what they have to say.

Regards,

Hans