Re: [PATCH v3 4/4] power: supply: Add driver for Cherry Trail Whiskey Cove PMIC Fuel Gauge

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

Hi,

On 25-03-17 19:42, Sebastian Reichel wrote:
> Hi Hans,
>
> On Sat, Mar 25, 2017 at 02:55:50PM +0100, Hans de Goede wrote:
>> Add a driver for the Cherry Trail Whiskey Cove PMIC Fuel Gauge.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>
> The driver looks fine to me. I think it would be nice to use
> regmap for accessing the device, though. Its capability to
> dump registers in debugfs is often useful, especially for
> reverse engineered drivers.

I just use i2cdump for that ..., TBH I don't see much added
value in using regmap here, but if you insist I can do a
v3 using regmap. Note this will require creating 2 regmaps,
one for each i2c client used.

> Also I assume, that you made sure the reported values are correctly
> scaled to uV/uA and not mV/mA?

Yes my values are in uV and uA the fuelgauge has quite
a good resolution for current and voltage measuring and
the mAh measures are in 0.5 mAh units.

> Just asking, since people regularly
> get this wrong and your scaling looks suspiciously small.

Understood.

Regards,

Hans


>
> -- Sebastian
>
>> ---
>> Changes in v2:
>> -There was no v2, it is skipped to the version in sync with the rest of
>>  the patch-set
>> Changes in v3:
>> -Change into a stand-alone power_supply battery driver instead of being a
>>  provider of extra properties for another battery driver
>> -Rename Kconfig symbol from CHT_WC_FUEL_GAUGE to BATTERY_INTEL_CHT_WC
>> ---
>>  drivers/power/supply/Kconfig             |   9 +
>>  drivers/power/supply/Makefile            |   1 +
>>  drivers/power/supply/cht_wc_fuel_gauge.c | 319 +++++++++++++++++++++++++++++++
>>  3 files changed, 329 insertions(+)
>>  create mode 100644 drivers/power/supply/cht_wc_fuel_gauge.c
>>
>> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
>> index fd93110..350d86a 100644
>> --- a/drivers/power/supply/Kconfig
>> +++ b/drivers/power/supply/Kconfig
>> @@ -538,4 +538,13 @@ config AXP20X_POWER
>>  	  This driver provides support for the power supply features of
>>  	  AXP20x PMIC.
>>
>> +config BATTERY_INTEL_CHT_WC
>> +	tristate "Intel Cherry Trail Whiskey Cove PMIC Fuel Gauge"
>> +	depends on INTEL_SOC_PMIC_CHTWC
>> +	help
>> +	  This adds support for the battery fuel gauge found in the Intel
>> +	  Cherry Trail Whiskey Cove PMIC. This driver allows monitoring
>> +	  of the charge level of the battery on Intel Cherry Trail systems
>> +	  with a Whiskey Cove PMIC.
>> +
>>  endif # POWER_SUPPLY
>> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
>> index 3789a2c..46dca5c 100644
>> --- a/drivers/power/supply/Makefile
>> +++ b/drivers/power/supply/Makefile
>> @@ -74,3 +74,4 @@ obj-$(CONFIG_CHARGER_TPS65090)	+= tps65090-charger.o
>>  obj-$(CONFIG_CHARGER_TPS65217)	+= tps65217_charger.o
>>  obj-$(CONFIG_AXP288_FUEL_GAUGE) += axp288_fuel_gauge.o
>>  obj-$(CONFIG_AXP288_CHARGER)	+= axp288_charger.o
>> +obj-$(CONFIG_BATTERY_INTEL_CHT_WC) += cht_wc_fuel_gauge.o
>> diff --git a/drivers/power/supply/cht_wc_fuel_gauge.c b/drivers/power/supply/cht_wc_fuel_gauge.c
>> new file mode 100644
>> index 0000000..0db83ad
>> --- /dev/null
>> +++ b/drivers/power/supply/cht_wc_fuel_gauge.c
>> @@ -0,0 +1,319 @@
>> +/*
>> + * Intel Cherry Trail Whiskey Cove Fuel Gauge driver
>> + * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/delay.h>
>> +#include <linux/extcon.h>
>> +#include <linux/i2c.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/mfd/intel_soc_pmic.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/power_supply.h>
>> +#include <linux/slab.h>
>> +#include <linux/workqueue.h>
>> +
>> +#define FG_CHARGE_NOW			0x05
>> +#define FG_VOLTAGE_NOW			0x09
>> +#define FG_CURRENT_NOW			0x0a
>> +#define FG_CURRENT_AVG			0x0b
>> +#define FG_CHARGE_FULL			0x10
>> +#define FG_CHARGE_DESIGN		0x18
>> +#define FG_VOLTAGE_AVG			0x19
>> +#define FG_VOLTAGE_OCV			0x1b /* Only updated during charging */
>> +
>> +#define PMIC_CHGRSTATUS			0x1a
>> +#define PMIC_CHGRSTATUS_NOT_CHARGING	BIT(0)
>> +
>> +#define CHT_WC_FG_PTYPE		4
>> +
>> +static const unsigned int charger_cable_ids[] = {
>> +	EXTCON_CHG_USB_SDP, EXTCON_CHG_USB_CDP,
>> +	EXTCON_CHG_USB_DCP, EXTCON_CHG_USB_ACA
>> +};
>> +
>> +struct cht_wc_fg_data {
>> +	struct device *dev;
>> +	/*
>> +	 * The ACPI _CRS table contains info for 4 clients, 1 for the charger-
>> +	 * manager part of the pmic and 3 for the actual fuel-gauge (which has
>> +	 * 3 i2c addresses) note we use only 1 fg address/client.
>> +	 */
>> +	struct i2c_client *pmic_client;
>> +	struct i2c_client *fg_client;
>> +	struct extcon_dev *extcon;
>> +	struct power_supply *battery;
>> +	struct work_struct changed_work;
>> +	struct notifier_block extcon_nb;
>> +};
>> +
>> +static int cht_wc_fg_read(struct cht_wc_fg_data *fg, u8 reg,
>> +			  union power_supply_propval *val, int scale,
>> +			  int sign_extend)
>> +{
>> +	int ret;
>> +
>> +	ret = i2c_smbus_read_word_data(fg->fg_client, reg);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	if (sign_extend)
>> +		ret = sign_extend32(ret, 15);
>> +
>> +	val->intval = ret * scale;
>> +
>> +	return 0;
>> +}
>> +
>> +static int cht_wc_fg_get_status(struct cht_wc_fg_data *fg,
>> +				union power_supply_propval *val)
>> +{
>> +	int i, ret;
>> +	bool vbus_present = false;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(charger_cable_ids); i++) {
>> +		if (extcon_get_state(fg->extcon, charger_cable_ids[i]) > 0) {
>> +			vbus_present = true;
>> +			break;
>> +		}
>> +	}
>> +
>> +	if (!vbus_present) {
>> +		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
>> +		return 0;
>> +	}
>> +
>> +	ret = i2c_smbus_read_byte_data(fg->pmic_client, PMIC_CHGRSTATUS);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/* Not charging while we have Vbus means the battery is full */
>> +	if (ret & PMIC_CHGRSTATUS_NOT_CHARGING)
>> +		val->intval = POWER_SUPPLY_STATUS_FULL;
>> +	else
>> +		val->intval = POWER_SUPPLY_STATUS_CHARGING;
>> +
>> +	return 0;
>> +}
>> +
>> +static int cht_wc_fg_get_property(struct power_supply *psy,
>> +	enum power_supply_property prop, union power_supply_propval *val)
>> +{
>> +	struct cht_wc_fg_data *fg = power_supply_get_drvdata(psy);
>> +	int ret = 0;
>> +
>> +	switch (prop) {
>> +	case POWER_SUPPLY_PROP_STATUS:
>> +		ret = cht_wc_fg_get_status(fg, val);
>> +		break;
>> +	case POWER_SUPPLY_PROP_PRESENT:
>> +		val->intval = 1;
>> +		break;
>> +	case POWER_SUPPLY_PROP_TECHNOLOGY:
>> +		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
>> +		break;
>> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
>> +		ret = cht_wc_fg_read(fg, FG_VOLTAGE_NOW, val, 75, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
>> +		ret = cht_wc_fg_read(fg, FG_VOLTAGE_AVG, val, 75, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
>> +		ret = cht_wc_fg_read(fg, FG_VOLTAGE_OCV, val, 75, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
>> +		ret = cht_wc_fg_read(fg, FG_CURRENT_NOW, val, 150, 1);
>> +		break;
>> +	case POWER_SUPPLY_PROP_CURRENT_AVG:
>> +		ret = cht_wc_fg_read(fg, FG_CURRENT_AVG, val, 150, 1);
>> +		break;
>> +	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
>> +		ret = cht_wc_fg_read(fg, FG_CHARGE_DESIGN, val, 500, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_CHARGE_FULL:
>> +		ret = cht_wc_fg_read(fg, FG_CHARGE_FULL, val, 500, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_CHARGE_NOW:
>> +		ret = cht_wc_fg_read(fg, FG_CHARGE_NOW, val, 500, 0);
>> +		break;
>> +	case POWER_SUPPLY_PROP_SCOPE:
>> +		val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
>> +		break;
>> +	default:
>> +		ret = -ENODATA;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static void cht_wc_fg_external_power_changed(struct power_supply *psy)
>> +{
>> +	struct cht_wc_fg_data *fg = power_supply_get_drvdata(psy);
>> +
>> +	schedule_work(&fg->changed_work);
>> +}
>> +
>> +static enum power_supply_property cht_wc_fg_properties[] = {
>> +	POWER_SUPPLY_PROP_STATUS,
>> +	POWER_SUPPLY_PROP_PRESENT,
>> +	POWER_SUPPLY_PROP_TECHNOLOGY,
>> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
>> +	POWER_SUPPLY_PROP_VOLTAGE_AVG,
>> +	POWER_SUPPLY_PROP_VOLTAGE_OCV,
>> +	POWER_SUPPLY_PROP_CURRENT_NOW,
>> +	POWER_SUPPLY_PROP_CURRENT_AVG,
>> +	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
>> +	POWER_SUPPLY_PROP_CHARGE_FULL,
>> +	POWER_SUPPLY_PROP_CHARGE_NOW,
>> +	POWER_SUPPLY_PROP_SCOPE,
>> +};
>> +
>> +static const struct power_supply_desc bat_desc = {
>> +	/* Matches charger.supplied_to for external_power_changed callback */
>> +	.name			= "main-battery",
>> +	.type			= POWER_SUPPLY_TYPE_BATTERY,
>> +	.properties		= cht_wc_fg_properties,
>> +	.num_properties		= ARRAY_SIZE(cht_wc_fg_properties),
>> +	.get_property		= cht_wc_fg_get_property,
>> +	.external_power_changed = cht_wc_fg_external_power_changed,
>> +};
>> +
>> +static void cht_wc_fg_changed_work(struct work_struct *work)
>> +{
>> +	struct cht_wc_fg_data *fg =
>> +		container_of(work, struct cht_wc_fg_data, changed_work);
>> +
>> +	/* Wait a bit to allow the fuel-gauge to also detect the new status */
>> +	msleep(200);
>> +
>> +	power_supply_changed(fg->battery);
>> +}
>> +
>> +static int cht_wc_fg_extcon_event(struct notifier_block *nb,
>> +				  unsigned long event, void *param)
>> +{
>> +	struct cht_wc_fg_data *fg =
>> +		container_of(nb, struct cht_wc_fg_data, extcon_nb);
>> +
>> +	schedule_work(&fg->changed_work);
>> +
>> +	return NOTIFY_OK;
>> +}
>> +
>> +static int cht_wc_fg_probe(struct i2c_client *client,
>> +			const struct i2c_device_id *i2c_id)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct power_supply_config bat_cfg = {};
>> +	struct cht_wc_fg_data *fg;
>> +	acpi_status status;
>> +	unsigned long long ptyp;
>> +	int ret;
>> +
>> +	status = acpi_evaluate_integer(ACPI_HANDLE(dev), "PTYP", NULL, &ptyp);
>> +	if (ACPI_FAILURE(status)) {
>> +		dev_err(dev, "Failed to get PTYPE\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/*
>> +	 * The same ACPI HID is used with different PMICs check PTYP to
>> +	 * ensure that we are dealing with a Whiskey Cove PMIC.
>> +	 */
>> +	if (ptyp != CHT_WC_FG_PTYPE)
>> +		return -ENODEV;
>> +
>> +	fg = devm_kzalloc(dev, sizeof(*fg), GFP_KERNEL);
>> +	if (!fg)
>> +		return -ENOMEM;
>> +
>> +	fg->dev = dev;
>> +	fg->pmic_client = client;
>> +	INIT_WORK(&fg->changed_work, cht_wc_fg_changed_work);
>> +
>> +	/*
>> +	 * We use the Whiskey Cove PMIC's pwrsrc detection block to see
>> +	 * if we are charging or not. We could access the pwrsrc regs
>> +	 * ourselves, but that requires re-implementing the extcon code,
>> +	 * so we just use the extcon interface.
>> +	 */
>> +	fg->extcon = extcon_get_extcon_dev("cht_wcove_pwrsrc");
>> +	if (!fg->extcon)
>> +		return -EPROBE_DEFER;
>> +
>> +	/*
>> +	 * The current resource settings table for the fuel gauge contains
>> +	 * multiple i2c devices on 2 different i2c-busses.
>> +	 */
>> +	fg->fg_client = i2c_acpi_new_device(dev, 1);
>> +	if (!fg->fg_client)
>> +		return -EPROBE_DEFER;
>> +
>> +	bat_cfg.drv_data = fg;
>> +	fg->battery = devm_power_supply_register(dev, &bat_desc, &bat_cfg);
>> +	if (IS_ERR(fg->battery)) {
>> +		i2c_unregister_device(fg->fg_client);
>> +		return PTR_ERR(fg->battery);
>> +	}
>> +
>> +	fg->extcon_nb.notifier_call = cht_wc_fg_extcon_event;
>> +	ret = devm_extcon_register_notifier(dev, fg->extcon, -1,
>> +					    &fg->extcon_nb);
>> +	if (ret) {
>> +		i2c_unregister_device(fg->fg_client);
>> +		return ret;
>> +	}
>> +
>> +	i2c_set_clientdata(client, fg);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cht_wc_fg_remove(struct i2c_client *i2c)
>> +{
>> +	struct cht_wc_fg_data *fg = i2c_get_clientdata(i2c);
>> +
>> +	i2c_unregister_device(fg->fg_client);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct i2c_device_id cht_wc_fg_i2c_id[] = {
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, cht_wc_fg_i2c_id);
>> +
>> +static const struct acpi_device_id cht_wc_fg_acpi_ids[] = {
>> +	{ "INT33FE", },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(acpi, cht_wc_fg_acpi_ids);
>> +
>> +static struct i2c_driver cht_wc_fg_driver = {
>> +	.driver	= {
>> +		.name	= "CHT Whiskey Cove PMIC Fuel Gauge",
>> +		.acpi_match_table = ACPI_PTR(cht_wc_fg_acpi_ids),
>> +	},
>> +	.probe = cht_wc_fg_probe,
>> +	.remove = cht_wc_fg_remove,
>> +	.id_table = cht_wc_fg_i2c_id,
>> +	.irq_index = 1,
>> +};
>> +
>> +module_i2c_driver(cht_wc_fg_driver);
>> +
>> +MODULE_DESCRIPTION("Intel CHT Whiskey Cove PMIC Fuel Gauge driver");
>> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
>> +MODULE_LICENSE("GPL");
>> --
>> 2.9.3
>>