Re: [PATCH 7/7] ARM: dts: s5pv210: Add charger support in Aries

[Jonathan Bakker]

On 2022-03-23 8:31 a.m., krzk@xxxxxxxxxx wrote:
> On 23/03/2022 16:03, Jonathan Bakker wrote:
>> Add charger-manager support to Aries boards to allow safe
>> charging of the battery without the need for userspace control.
>>
>> Signed-off-by: Jonathan Bakker <xc-racer2@xxxxxxx>
>> ---
>>  arch/arm/boot/dts/s5pv210-fascinate4g.dts | 162 ++++++++++++++++++++++
>>  arch/arm/boot/dts/s5pv210-galaxys.dts     | 144 +++++++++++++++++++
>>  2 files changed, 306 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/s5pv210-fascinate4g.dts b/arch/arm/boot/dts/s5pv210-fascinate4g.dts
>> index 7427c84f1126..9530231b7a70 100644
>> --- a/arch/arm/boot/dts/s5pv210-fascinate4g.dts
>> +++ b/arch/arm/boot/dts/s5pv210-fascinate4g.dts
>> @@ -57,6 +57,168 @@
>>  		pinctrl-0 = <&main_micbias_ena>;
>>  	};
>>  
>> +	thermal-zones {
>> +		batt_thermal: batt-thermal {
>> +			polling-delay-passive = <60000>; /* 60 seconds */
> 
> There is no passive cooling device, so why do you need it?
> 

The charger manager code needs a passive cooling device, so that's
why this is present here.

>> +			polling-delay = <600000>; /* 600 seconds */
>> +
>> +			thermal-sensors = <&batt_thermistor>;
>> +		};
>> +	};
>> +
>> +	batt_thermistor: thermal-sensor-0 {
>> +		compatible = "generic-adc-thermal";
>> +		#thermal-sensor-cells = <0>;
>> +		io-channels = <&adc 6>;
>> +		io-channel-names = "sensor-channel";
>> +
>> +		temperature-lookup-table = <
>> +			(-20000) 1859
>> +			(-19000) 1846
>> +			(-18000) 1832
>> +			(-17000) 1818
>> +			(-16000) 1804
>> +			(-15000) 1790
>> +			(-14000) 1773
>> +			(-13000) 1756
>> +			(-12000) 1739
>> +			(-11000) 1722
>> +			(-10000) 1705
>> +			(-9000) 1691
>> +			(-8000) 1677
>> +			(-7000) 1663
>> +			(-6000) 1649
>> +			(-5000) 1635
>> +			(-4000) 1550
>> +			(-3000) 1510
>> +			(-2000) 1500
>> +			(-1000) 1490
>> +			0 1480
>> +			1000 1470
>> +			2000 1460
>> +			3000 1450
>> +			4000 1430
>> +			5000 1420
>> +			6000 1406
>> +			7000 1386
>> +			8000 1366
>> +			9000 1346
>> +			10000 1326
>> +			11000 1302
>> +			12000 1278
>> +			13000 1254
>> +			14000 1230
>> +			15000 1206
>> +			16000 1182
>> +			17000 1158
>> +			18000 1134
>> +			19000 1110
>> +			20000 1086
>> +			21000 1059
>> +			22000 1035
>> +			23000 1011
>> +			24000 987
>> +			25000 963
>> +			26000 937
>> +			27000 913
>> +			28000 889
>> +			29000 865
>> +			30000 841
>> +			31000 816
>> +			32000 794
>> +			33000 772
>> +			34000 750
>> +			35000 728
>> +			36000 708
>> +			37000 690
>> +			38000 672
>> +			39000 654
>> +			40000 636
>> +			41000 616
>> +			42000 599
>> +			43000 580
>> +			44000 565
>> +			45000 548
>> +			46000 529
>> +			47000 512
>> +			48000 495
>> +			49000 478
>> +			50000 461
>> +			51000 440
>> +			52000 431
>> +			53000 416
>> +			54000 405
>> +			55000 396
>> +			56000 375
>> +			57000 360
>> +			58000 347
>> +			59000 334
>> +			60000 325
>> +			61000 311
>> +			62000 303
>> +			63000 296
>> +			64000 290
>> +			65000 279
>> +			66000 265
>> +			67000 254
>> +			68000 240
>> +			69000 220
>> +			70000 206>;
>> +	};
>> +
>> +	charger_manager: charger-manager-0 {
>> +		compatible = "charger-manager";
> 
> Sorry, this is not a hardware. It's a hack to configure kernel charging
> driver via DT which was made deprecated.

Thanks, I missed the deprecation notice in the binding file.

What would be the better way of creating a functional charging system?
A new device-specific driver?  Userspace monitoring of temperature/connected
device and extensions to the max8998 driver for enabling/disabling/configuring
charging via the power supply subsystem instead of the regulator subsystem?
Something else?

The way I understand the charging system, there is

- The fuelgauge (max17042)
- The max8998 charger portion, including the ability to vary the current
- The thermistor for checking battery temperature
- The FSA9480 to determine what sort of cable is connected

Thanks,
Jonathan

> 
> Best regards,
> Krzysztof
>