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

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

Add a driver for the Cherry Trail Whiskey Cove PMIC Fuel Gauge.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
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