Re: [External] [PATCH 4/4] platform/x86: thinkpad_acpi: support inhibit-charge

[Mark Pearson <markpearson@lenovo.com>]

Hi Thomas

On 2021-11-16 18:44, Thomas Weißschuh wrote:
> Hi Mark,
> 
> On 2021-11-16 15:52-0500, Mark Pearson wrote:
>> On 2021-11-13 05:42, Thomas Weißschuh wrote:
>>> This adds support for the inhibit-charge charge_behaviour through the
>>> embedded controller of ThinkPads.
>>>
>>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>>>
>>> ---
>>>
>>> This patch is based on https://lore.kernel.org/platform-driver-x86/d2808930-5840-6ffb-3a59-d235cdb1fe16@gmail.com/ ---
>>>  drivers/platform/x86/thinkpad_acpi.c | 55 +++++++++++++++++++++++++++-
>>>  1 file changed, 53 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
>>> index e8c98e9aff71..7cd6475240b2 100644
>>> --- a/drivers/platform/x86/thinkpad_acpi.c
>>> +++ b/drivers/platform/x86/thinkpad_acpi.c
>>> @@ -9321,6 +9321,8 @@ static struct ibm_struct mute_led_driver_data = {
>>>  #define SET_STOP	"BCSS"
>>>  #define GET_DISCHARGE	"BDSG"
>>>  #define SET_DISCHARGE	"BDSS"
>>> +#define GET_INHIBIT	"PSSG"
>>> +#define SET_INHIBIT	"BICS"
>>>  
>>>  enum {
>>>  	BAT_ANY = 0,
>>> @@ -9338,6 +9340,7 @@ enum {
>>>  	THRESHOLD_START,
>>>  	THRESHOLD_STOP,
>>>  	FORCE_DISCHARGE,
>>> +	INHIBIT_CHARGE,
>>>  };
>>>  
>>>  struct tpacpi_battery_data {
>>> @@ -9409,6 +9412,13 @@ static int tpacpi_battery_get(int what, int battery, int *ret)
>>>  		/* The force discharge status is in bit 0 */
>>>  		*ret = *ret & 0x01;
>>>  		return 0;
>>> +	case INHIBIT_CHARGE:
>>> +		/* This is actually reading peak shift state, like tpacpi-bat does */
>>> +		if ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_INHIBIT, ret, battery))
>>> +			return -ENODEV;
>>> +		/* The inhibit charge status is in bit 0 */
>>> +		*ret = *ret & 0x01;
>>> +		return 0;
>>>  	default:
>>>  		pr_crit("wrong parameter: %d", what);
>>>  		return -EINVAL;
>>> @@ -9447,6 +9457,22 @@ static int tpacpi_battery_set(int what, int battery, int value)
>>>  			return -ENODEV;
>>>  		}
>>>  		return 0;
>>> +	case INHIBIT_CHARGE:
>>> +		/* When setting inhibit charge, we set a default value of
>>> +		 * always breaking on AC detach and the effective time is set to
>>> +		 * be permanent.
>>> +		 * The battery ID is in bits 4-5, 2 bits,
>>> +		 * the effective time is in bits 8-23, 2 bytes.
>>> +		 * A time of FFFF indicates forever.
>>> +		 */
>>> +		param = value;
>>> +		param |= battery << 4;
>>> +		param |= 0xFFFF << 8;
>>> +		if (ACPI_FAILURE(tpacpi_battery_acpi_eval(SET_INHIBIT, &ret, param))) {
>>> +			pr_err("failed to set inhibit charge on %d", battery);
>>> +			return -ENODEV;
>>> +		}
>>> +		return 0;
>>>  	default:
>>>  		pr_crit("wrong parameter: %d", what);
>>>  		return -EINVAL;
>>> @@ -9467,6 +9493,8 @@ static int tpacpi_battery_probe(int battery)
>>>  	 * 4) Check for support
>>>  	 * 5) Get the current force discharge status
>>>  	 * 6) Check for support
>>> +	 * 7) Get the current inhibit charge status
>>> +	 * 8) Check for support
>>>  	 */
>>>  	if (acpi_has_method(hkey_handle, GET_START)) {
>>>  		if ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_START, &ret, battery)) {
>>> @@ -9513,6 +9541,16 @@ static int tpacpi_battery_probe(int battery)
>>>  			battery_info.batteries[battery].charge_behaviours |=
>>>  				BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE);
>>>  	}
>>> +	if (acpi_has_method(hkey_handle, GET_INHIBIT)) {
>>> +		if (ACPI_FAILURE(tpacpi_battery_acpi_eval(GET_INHIBIT, &ret, battery))) {
>>> +			pr_err("Error probing battery inhibit charge; %d\n", battery);
>>> +			return -ENODEV;
>>> +		}
>>> +		/* Support is marked in bit 5 */
>>> +		if (ret & BIT(5))
>>> +			battery_info.batteries[battery].charge_behaviours |=
>>> +				BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE);
>>> +	}
>>>  
>>>  	battery_info.batteries[battery].charge_behaviours |=
>>>  		BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO);
>>> @@ -9673,6 +9711,11 @@ static ssize_t charge_behaviour_show(struct device *dev,
>>>  			return -ENODEV;
>>>  		if (ret)
>>>  			active = POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE;
>>> +	} else if (available & BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE)) {
>>> +		if (tpacpi_battery_get(INHIBIT_CHARGE, battery, &ret))
>>> +			return -ENODEV;
>>> +		if (ret)
>>> +			active = POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE;
>>>  	}
>>>  
>>>  	return power_supply_charge_behaviour_show(dev, available, active, buf);
>>> @@ -9710,12 +9753,20 @@ static ssize_t charge_behaviour_store(struct device *dev,
>>>  	switch (selected) {
>>>  	case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
>>>  		ret = tpacpi_battery_set(FORCE_DISCHARGE, battery, 0);
>>> -		if (ret < 0)
>>> +		ret = tpacpi_battery_set(INHIBIT_CHARGE, battery, 0) || ret;
>>> +		if (ret)
>>>  			return ret;
>>>  		break;
>>>  	case POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE:
>>>  		ret = tpacpi_battery_set(FORCE_DISCHARGE, battery, 1);
>>> -		if (ret < 0)
>>> +		ret = tpacpi_battery_set(INHIBIT_CHARGE, battery, 0) || ret;
>>> +		if (ret)
>>> +			return ret;
>>> +		break;
>>> +	case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
>>> +		ret = tpacpi_battery_set(FORCE_DISCHARGE, battery, 0);
>>> +		ret = tpacpi_battery_set(INHIBIT_CHARGE, battery, 1) || ret;
>>> +		if (ret)
>>>  			return ret;
>>>  		break;
>>>  	default:
>>>
>>
>> I can confirm the bit fields are correct for these calls (as for the
>> previous patch)
> 
> Thanks!
> 
> Could you doublecheck the behavior for multiple batteries to maybe find a
> reason why BAT1 is not inhibited as reported by Thomas Koch [0]?
> 
>> Couple of things to note, based on feedback previously from the FW team
>> that I found when digging thru my battery related emails.
>>
>> "Lenovo doesn't officially support the use of these calls - they're
>> intended for internal use" (at this point in time - there is some
>> discussion about battery recalibration support but I don't have details
>> I can share there yet).
>>
>> The FW team also noted that:
>>
>> "Actual battery charging/discharging behaviors are managed by ECFW. So
>> the request of BDSS/BICS method may be rejected by ECFW for the current
>> battery mode/status. You have to check if the request of the method is
>> actually applied or not"
>>
>> So for the calls above (and for the BDSS calls in the previous patch) it
>> would be good to do a read back of the setting to ensure it has
>> completed successfully.
> 
> I'll add that for v2.
> 
>> Hope that helps
> 
> It does, thanks!
> 
> Thomas
> 
> [0] https://lore.kernel.org/platform-driver-x86/9cebba85-f399-a7aa-91f7-237852338dc5@gmx.net/>> 
I got confirmation that:

<quote>
BDSS have to be used with specific battery. Please use with Primary(=1b)
or Secondary(2b) as Battery ID (Bit9-8)

Bit 9-8: Battery ID
= 0: Any battery
= 1: Primary battery
= 2: Secondary battery
</quote>

It seems you can't use BDSS with all batteries.
I'll confirm on BICS what the limitations are, they didn't update on
that piece yet I'm afraid. Unfortunately I don't think I have any
systems with two batteries to test myself.

Mark