[PATCH v3 1/2] power: supply: add sbs-charger driver

From: Nicolas Saenz Julienne
Date: Thu Nov 24 2016 - 07:35:12 EST

This adds support for sbs-charger compilant chips as defined here:
http://sbs-forum.org/specs/sbc110.pdf

This was tested on a arm board connected to an LTC41000 battery charger
chip.

Signed-off-by: Nicolas Saenz Julienne <nicolas.saenz@xxxxxxxxxx>
---
v2 -> v3:
- add readable_reg() function to regmap config
- update compatible strings with part number

v1 -> v2:
- add spec link in header
- use proper gpio/interrupt interface
- update regmap configuration (max register & endianness)
- dropped oldschool .supplied_to assignments
- use devm_* APIs
drivers/power/supply/Kconfig | 6 +
drivers/power/supply/Makefile | 1 +
drivers/power/supply/sbs-charger.c | 275 +++++++++++++++++++++++++++++++++++++
3 files changed, 282 insertions(+)
create mode 100644 drivers/power/supply/sbs-charger.c

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 76806a0..42877ff 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -164,6 +164,12 @@ config BATTERY_SBS
Say Y to include support for SBS battery driver for SBS-compliant
gas gauges.

+config CHARGER_SBS
+ tristate "SBS Compliant charger"
+ depends on I2C
+ help
+ Say Y to include support for SBS compilant battery chargers.
+
config BATTERY_BQ27XXX
tristate "BQ27xxx battery driver"
help
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 36c599d..06d9ef5 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_BATTERY_COLLIE) += collie_battery.o
obj-$(CONFIG_BATTERY_IPAQ_MICRO) += ipaq_micro_battery.o
obj-$(CONFIG_BATTERY_WM97XX) += wm97xx_battery.o
obj-$(CONFIG_BATTERY_SBS) += sbs-battery.o
+obj-$(CONFIG_CHARGER_SBS) += sbs-charger.o
obj-$(CONFIG_BATTERY_BQ27XXX) += bq27xxx_battery.o
obj-$(CONFIG_BATTERY_BQ27XXX_I2C) += bq27xxx_battery_i2c.o
obj-$(CONFIG_BATTERY_DA9030) += da9030_battery.o
diff --git a/drivers/power/supply/sbs-charger.c b/drivers/power/supply/sbs-charger.c
new file mode 100644
index 0000000..2c4cd45
--- /dev/null
+++ b/drivers/power/supply/sbs-charger.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright (c) 2016, Prodys S.L.
+ *
+ * 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 adds support for sbs-charger compilant chips as defined here:
+ * http://sbs-forum.org/specs/sbc110.pdf
+ *
+ * Implemetation based on sbs-battery.c
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/power_supply.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/regmap.h>
+#include <linux/of_gpio.h>
+#include <linux/bitops.h>
+
+#define SBS_CHARGER_REG_SPEC_INFO 0x11
+#define SBS_CHARGER_REG_STATUS 0x13
+#define SBS_CHARGER_REG_ALARM_WARNING 0x16
+
+#define SBS_CHARGER_STATUS_CHARGE_INHIBITED BIT(1)
+#define SBS_CHARGER_STATUS_RES_COLD BIT(9)
+#define SBS_CHARGER_STATUS_RES_HOT BIT(10)
+#define SBS_CHARGER_STATUS_BATTERY_PRESENT BIT(14)
+#define SBS_CHARGER_STATUS_AC_PRESENT BIT(15)
+
+#define SBS_CHARGER_POLL_TIME 500
+
+struct sbs_info {
+ struct i2c_client *client;
+ struct power_supply *power_supply;
+ struct regmap *regmap;
+ struct delayed_work work;
+ unsigned int last_state;
+};
+
+static int sbs_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct sbs_info *chip = power_supply_get_drvdata(psy);
+ unsigned int reg;
+
+ reg = chip->last_state;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_PRESENT:
+ val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
+ break;
+
+ case POWER_SUPPLY_PROP_ONLINE:
+ val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
+ break;
+
+ case POWER_SUPPLY_PROP_STATUS:
+ val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+
+ if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
+ val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+ else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
+ !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
+ val->intval = POWER_SUPPLY_STATUS_CHARGING;
+ else
+ val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+
+ break;
+
+ case POWER_SUPPLY_PROP_HEALTH:
+ if (reg & SBS_CHARGER_STATUS_RES_COLD)
+ val->intval = POWER_SUPPLY_HEALTH_COLD;
+ if (reg & SBS_CHARGER_STATUS_RES_HOT)
+ val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+ else
+ val->intval = POWER_SUPPLY_HEALTH_GOOD;
+
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int sbs_check_state(struct sbs_info *chip)
+{
+ unsigned int reg;
+ int ret;
+
+ ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &reg);
+ if (!ret && reg != chip->last_state) {
+ chip->last_state = reg;
+ power_supply_changed(chip->power_supply);
+ return 1;
+ }
+
+ return 0;
+}
+
+static void sbs_delayed_work(struct work_struct *work)
+{
+ struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
+
+ sbs_check_state(chip);
+
+ schedule_delayed_work(&chip->work,
+ msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
+}
+
+static irqreturn_t sbs_irq_thread(int irq, void *data)
+{
+ struct sbs_info *chip = data;
+ int ret;
+
+ ret = sbs_check_state(chip);
+
+ return ret ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static enum power_supply_property sbs_properties[] = {
+ POWER_SUPPLY_PROP_STATUS,
+ POWER_SUPPLY_PROP_PRESENT,
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_HEALTH,
+};
+
+static bool sbs_readable_reg(struct device *dev, unsigned int reg)
+{
+ if (reg < SBS_CHARGER_REG_SPEC_INFO)
+ return false;
+ else
+ return true;
+}
+
+static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case SBS_CHARGER_REG_STATUS:
+ return true;
+ }
+
+ return false;
+}
+
+static const struct regmap_config sbs_regmap = {
+ .reg_bits = 8,
+ .val_bits = 16,
+ .max_register = SBS_CHARGER_REG_ALARM_WARNING,
+ .readable_reg = sbs_readable_reg,
+ .volatile_reg = sbs_volatile_reg,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
+};
+
+static const struct power_supply_desc sbs_desc = {
+ .name = "sbs-charger",
+ .type = POWER_SUPPLY_TYPE_MAINS,
+ .properties = sbs_properties,
+ .num_properties = ARRAY_SIZE(sbs_properties),
+ .get_property = sbs_get_property,
+};
+
+static int sbs_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct power_supply_config psy_cfg = {};
+ struct sbs_info *chip;
+ int ret, val;
+
+ chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->client = client;
+ psy_cfg.of_node = client->dev.of_node;
+ psy_cfg.drv_data = chip;
+
+ i2c_set_clientdata(client, chip);
+
+ chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
+ if (IS_ERR(chip->regmap))
+ return PTR_ERR(chip->regmap);
+
+ /*
+ * Before we register, we need to make sure we can actually talk
+ * to the battery.
+ */
+ ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
+ if (ret) {
+ dev_err(&client->dev, "Failed to get device status\n");
+ return ret;
+ }
+ chip->last_state = val;
+
+ chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc,
+ &psy_cfg);
+ if (IS_ERR(chip->power_supply)) {
+ dev_err(&client->dev, "Failed to register power supply\n");
+ return PTR_ERR(chip->power_supply);
+ }
+
+ /*
+ * The sbs-charger spec doesn't impose the use of an interrupt. So in
+ * the case it wasn't provided we use polling in order get the charger's
+ * status.
+ */
+ if (client->irq) {
+ ret = devm_request_threaded_irq(&client->dev, client->irq,
+ NULL, sbs_irq_thread,
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ dev_name(&client->dev), chip);
+ if (ret) {
+ dev_err(&client->dev, "Failed to request irq, %d\n", ret);
+ return ret;
+ }
+ } else {
+ INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
+ schedule_delayed_work(&chip->work,
+ msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
+ }
+
+ dev_info(&client->dev,
+ "%s: smart charger device registered\n", client->name);
+
+ return 0;
+}
+
+static int sbs_remove(struct i2c_client *client)
+{
+ struct sbs_info *chip = i2c_get_clientdata(client);
+
+ cancel_delayed_work_sync(&chip->work);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id sbs_dt_ids[] = {
+ { .compatible = "lltc,ltc4100" },
+ { .compatible = "sbs,sbs-charger" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sbs_dt_ids);
+#endif
+
+static const struct i2c_device_id sbs_id[] = {
+ { "sbs-charger", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, sbs_id);
+
+static struct i2c_driver sbs_driver = {
+ .probe = sbs_probe,
+ .remove = sbs_remove,
+ .id_table = sbs_id,
+ .driver = {
+ .name = "sbs-charger",
+ .of_match_table = of_match_ptr(sbs_dt_ids),
+ },
+};
+module_i2c_driver(sbs_driver);
+
+MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@xxxxxxxxx>");
+MODULE_DESCRIPTION("SBS smart charger driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4