linux-kernel - Re: [PATCH v4 12/20] power: supply: bq25890: Support higher charging voltages through Pump Express+ protocol

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Date:   Mon, 31 Jan 2022 16:18:23 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Andy Shevchenko <andriy.shevchenko@...el.com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andy@...nel.org>,
        Wolfram Sang <wsa@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Sebastian Reichel <sre@...nel.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Ard Biesheuvel <ardb@...nel.org>, Len Brown <lenb@...nel.org>,
        linux-acpi@...r.kernel.org, Yauhen Kharuzhy <jekhor@...il.com>,
        Tsuchiya Yuto <kitakar@...il.com>,
        Fabio Aiuto <fabioaiuto83@...il.com>,
        platform-driver-x86@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org
Subject: Re: [PATCH v4 12/20] power: supply: bq25890: Support higher charging
 voltages through Pump Express+ protocol

Hi,

On 1/31/22 14:48, Andy Shevchenko wrote:
> On Sun, Jan 30, 2022 at 09:45:49PM +0100, Hans de Goede wrote:
>> From: Yauhen Kharuzhy <jekhor@...il.com>
>>
>> Add a "linux,pump-express-vbus-max" property which indicates if the Pump
>> Express+ protocol should be used to increase the charging protocol.
>>
>> If this new property is set and a DCP charger is detected then request
>> a higher charging voltage through the Pump Express+ protocol.
>>
>> So far this new property is only used on x86/ACPI (non devicetree) devs,
>> IOW it is not used in actual devicetree files. The devicetree-bindings
>> maintainers have requested properties like these to not be added to the
>> devicetree-bindings, so the new property is deliberately not added
>> to the existing devicetree-bindings.
>>
>> Changes by Hans de Goede:
>> - Port to my bq25890 patch-series + various cleanups
>> - Make behavior configurable through a new "linux,pump-express-vbus-max"
>>   device-property
>> - Sleep 1 second before re-checking the Vbus voltage after requesting
>>   it to be raised, to ensure that the ADC has time to sampled the new Vbus
>> - Add VBUSV bq25890_tables[] entry and use it in bq25890_get_vbus_voltage()
>> - Tweak commit message
> 
> ...
> 
>> +static void bq25890_pump_express_work(struct work_struct *data)
>> +{
>> +	struct bq25890_device *bq =
>> +		container_of(data, struct bq25890_device, pump_express_work.work);
>> +	int voltage, i, ret;
>> +
>> +	dev_dbg(bq->dev, "Start to request input voltage increasing\n");
>> +
>> +	/* Enable current pulse voltage control protocol */
>> +	ret = bq25890_field_write(bq, F_PUMPX_EN, 1);
>> +	if (ret < 0)
>> +		goto error_print;
>> +
>> +	for (i = 0; i < PUMP_EXPRESS_MAX_TRIES; i++) {
> 
>> +		voltage = bq25890_get_vbus_voltage(bq);
>> +		if (voltage < 0)
>> +			goto error_print;
> 
> It also can be (at least in align with the rest error paths)
> 
> 		ret = bq25890_get_vbus_voltage(bq);
> 		if (ret < 0)
> 			goto error_print;
> 		voltage = ret;
> 
> followed up (but not necessarily)...

The suggested pattern is useful when ret needs to be set on the error-exit
path, but we are not doing that here. So I prefer to just keep this as is.

Regards,

Hans



> 
>> +		dev_dbg(bq->dev, "input voltage = %d uV\n", voltage);
>> +
>> +		if ((voltage + PUMP_EXPRESS_VBUS_MARGIN_uV) >
>> +					bq->pump_express_vbus_max)
>> +			break;
>> +
>> +		ret = bq25890_field_write(bq, F_PUMPX_UP, 1);
>> +		if (ret < 0)
>> +			goto error_print;
>> +
>> +		/* Note a single PUMPX up pulse-sequence takes 2.1s */
>> +		ret = regmap_field_read_poll_timeout(bq->rmap_fields[F_PUMPX_UP],
>> +						     ret, !ret, 100000, 3000000);
>> +		if (ret < 0)
>> +			goto error_print;
>> +
>> +		/* Make sure ADC has sampled Vbus before checking again */
>> +		msleep(1000);
>> +	}
>> +
>> +	bq25890_field_write(bq, F_PUMPX_EN, 0);
>> +
>> +	dev_info(bq->dev, "Hi-voltage charging requested, input voltage is %d mV\n",
>> +		 voltage);
> 
>> +	return;
>> +error_print:
> 
> 	if (ret < 0)
> 
> But it's up to you.
> 
>> +	dev_err(bq->dev, "Failed to request hi-voltage charging\n");
>> +}
>