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    Subject[PATCH 14/15] power: supply: Add driver for Cherry Trail Whiskey Cove PMIC Fuel Gauge
    Date
    Add a driver for the Cherry Trail Whiskey Cove PMIC Fuel Gauge, note
    the Cherry Trail Whiskey Cove PMIC Fuel Gauge block is purely a fuel gauge
    and not a full battery controller. As such it offers a platform_data
    callback for extra power_supply properties for the actual external-charger
    ic driver and does not register a power_supply itself.

    Signed-off-by: Hans de Goede <hdegoede@redhat.com>
    ---
    drivers/power/supply/Kconfig | 9 ++
    drivers/power/supply/Makefile | 1 +
    drivers/power/supply/cht_wc_fuel_gauge.c | 209 +++++++++++++++++++++++++++++++
    include/linux/power/cht_wc_fuel_gauge.h | 21 ++++
    4 files changed, 240 insertions(+)
    create mode 100644 drivers/power/supply/cht_wc_fuel_gauge.c
    create mode 100644 include/linux/power/cht_wc_fuel_gauge.h

    diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
    index fd93110..34ebfca 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 CHT_WC_FUEL_GAUGE
    + 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..702e28a 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_CHT_WC_FUEL_GAUGE) += 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..56f6e5a
    --- /dev/null
    +++ b/drivers/power/supply/cht_wc_fuel_gauge.c
    @@ -0,0 +1,209 @@
    +/*
    + * Intel CHT 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 version
    + * 2 as published by the Free Software Foundation.
    + *
    + * 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.
    + *
    + * Cherrytrail Whiskey Cove devices have 2 functional blocks which interact
    + * with the battery.
    + *
    + * 1) The fuel-gauge which is build into the Whiskey Cove PMIC, but has its
    + * own i2c bus and i2c client addresses separately from the rest of the PMIC.
    + * That block is what this driver is for.
    + *
    + * 2) An external charger IC, which is connected to the SMBUS controller
    + * which is part of the rest of the Whiskey Cove PMIC, mfd/intel_cht_wc.c
    + * registers a platform device for the SMBUS controller and
    + * i2c/busses/i2c-cht-wc.c contains the i2c-adapter driver for this.
    + *
    + * However we want to present this as a single power_supply device to
    + * userspace. So this driver offers a callback to get the fuel-gauge
    + * power_supply properties, which gets passed to the external charger
    + * driver via i2c_board_info when i2c-cht-wc.c calls i2c_new_device().
    + */
    +
    +#include <linux/acpi.h>
    +#include <linux/delay.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/power/cht_wc_fuel_gauge.h>
    +#include <linux/slab.h>
    +
    +#define REG_CHARGE_NOW 0x05
    +#define REG_VOLTAGE_NOW 0x09
    +#define REG_CURRENT_NOW 0x0a
    +#define REG_CURRENT_AVG 0x0b
    +#define REG_CHARGE_FULL 0x10
    +#define REG_CHARGE_DESIGN 0x18
    +#define REG_VOLTAGE_AVG 0x19
    +#define REG_VOLTAGE_OCV 0x1b /* Only updated during charging */
    +
    +#define CHT_WC_FG_PTYPE 4
    +
    +struct cht_wc_fg_data {
    + struct device *dev;
    + struct i2c_client *client;
    +};
    +
    +static DEFINE_MUTEX(cht_wc_fg_mutex);
    +static struct cht_wc_fg_data *cht_wc_fg;
    +
    +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->client, reg);
    + if (ret < 0)
    + return ret;
    +
    + if (sign_extend)
    + ret = sign_extend32(ret, 15);
    +
    + val->intval = ret * scale;
    +
    + return 0;
    +}
    +
    +int cht_wc_fg_get_property(enum power_supply_property prop,
    + union power_supply_propval *val)
    +{
    + int ret = 0;
    +
    + mutex_lock(&cht_wc_fg_mutex);
    +
    + if (!cht_wc_fg) {
    + ret = -ENXIO;
    + goto out_unlock;
    + }
    +
    + switch (prop) {
    + case POWER_SUPPLY_PROP_VOLTAGE_NOW:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_VOLTAGE_NOW, val, 75, 0);
    + break;
    + case POWER_SUPPLY_PROP_VOLTAGE_AVG:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_VOLTAGE_AVG, val, 75, 0);
    + break;
    + case POWER_SUPPLY_PROP_VOLTAGE_OCV:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_VOLTAGE_OCV, val, 75, 0);
    + break;
    + case POWER_SUPPLY_PROP_CURRENT_NOW:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_CURRENT_NOW, val, 150, 1);
    + break;
    + case POWER_SUPPLY_PROP_CURRENT_AVG:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_CURRENT_AVG, val, 150, 1);
    + break;
    + case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_CHARGE_DESIGN, val, 500, 0);
    + break;
    + case POWER_SUPPLY_PROP_CHARGE_FULL:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_CHARGE_FULL, val, 500, 0);
    + break;
    + case POWER_SUPPLY_PROP_CHARGE_NOW:
    + ret = cht_wc_fg_read(cht_wc_fg, REG_CHARGE_NOW, val, 500, 0);
    + break;
    + default:
    + ret = -ENODATA;
    + }
    +out_unlock:
    + mutex_unlock(&cht_wc_fg_mutex);
    + return ret;
    +}
    +EXPORT_SYMBOL_GPL(cht_wc_fg_get_property);
    +
    +static int cht_wc_fg_probe(struct i2c_client *client,
    + const struct i2c_device_id *i2c_id)
    +{
    + struct device *dev = &client->dev;
    + struct cht_wc_fg_data *fg;
    + acpi_status status;
    + unsigned long long ptyp;
    +
    + fg = devm_kzalloc(dev, sizeof(*fg), GFP_KERNEL);
    + if (!fg)
    + return -ENOMEM;
    +
    + 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->dev = dev;
    + /*
    + * The current resource settings table for the fuel gauge contains
    + * multiple i2c devices on 2 different i2c-busses. The one we actually
    + * want is the second resource (index 1).
    + */
    + fg->client = i2c_acpi_new_device(dev, 1);
    + if (!fg->client)
    + return -EPROBE_DEFER;
    +
    + i2c_set_clientdata(client, fg);
    +
    + mutex_lock(&cht_wc_fg_mutex);
    + cht_wc_fg = fg;
    + mutex_unlock(&cht_wc_fg_mutex);
    +
    + return 0;
    +}
    +
    +static int cht_wc_fg_remove(struct i2c_client *i2c)
    +{
    + struct cht_wc_fg_data *fg = i2c_get_clientdata(i2c);
    +
    + mutex_lock(&cht_wc_fg_mutex);
    + cht_wc_fg = NULL;
    + mutex_unlock(&cht_wc_fg_mutex);
    +
    + i2c_unregister_device(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");
    diff --git a/include/linux/power/cht_wc_fuel_gauge.h b/include/linux/power/cht_wc_fuel_gauge.h
    new file mode 100644
    index 0000000..4b4e051
    --- /dev/null
    +++ b/include/linux/power/cht_wc_fuel_gauge.h
    @@ -0,0 +1,21 @@
    +/*
    + * Intel CHT 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 version
    + * 2 as published by the Free Software Foundation.
    + *
    + * 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.
    + */
    +
    +#ifndef __CHT_WC_FUEL_GAUGE_H
    +#define __CHT_WC_FUEL_GAUGE_H
    +
    +int cht_wc_fg_get_property(enum power_supply_property prop,
    + union power_supply_propval *val);
    +
    +#endif
    --
    2.9.3
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