power: supply: Introduce MM8013 fuel gauge driver

Add a driver for the Mitsumi MM8013 fuel gauge. The driver is a vastly
cleaned up and improved version of the one that shipped in some obscure
Lenovo downstream kernel [1], with some register definitions borrowed from
ChromeOS EC platform code [2].

[1] https://github.com/adazem009/kernel_lenovo_bengal/commit/b6b346427a871715709bd22aae449b9383f3b66b
[2] https://chromium.googlesource.com/chromiumos/platform/ec/+/master/driver/battery/mm8013.h

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20230621-topic-mm8013-v4-3-975aecd173ed@linaro.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index 90f13281d29708439ba448d26308109a3cfd747b..fb458f7e397cd8b128846ee235597fa35a468362 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14376,6 +14376,11 @@ W:     https://linuxtv.org
 T:     git git://linuxtv.org/media_tree.git
 F:     drivers/media/radio/radio-miropcm20*
 
+MITSUMI MM8013 FG DRIVER
+M:     Konrad Dybcio <konradybcio@kernel.org>
+F:     Documentation/devicetree/bindings/power/supply/mitsumi,mm8013.yaml
+F:     drivers/power/supply/mm8013.c
+
 MMP SUPPORT
 R:     Lubomir Rintel <lkundrak@v3.sk>
 L:     linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index d99db3a049f2c0af5cc73a7c1eeb5bd677258657..c816dc4265df7012e9ffc09ba3bd2d4fb2a640f3 100644 (file)
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -951,4 +951,13 @@ config CHARGER_QCOM_SMB2
          adds support for the SMB2 switch mode battery charger found
          in PMI8998 and related PMICs.
 
+config FUEL_GAUGE_MM8013
+       tristate "Mitsumi MM8013 fuel gauge driver"
+       depends on I2C
+       help
+         Say Y here to enable the Mitsumi MM8013 fuel gauge driver.
+         It enables the monitoring of many battery parameters, including
+         the state of charge, temperature, cycle count, actual and design
+         capacity, etc.
+
 endif # POWER_SUPPLY

diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index a8a9fa6de1e9a039c397bb18a67387ca919b090c..ba2c41f060bed6545dacbcdbedb69b1533bd6ba8 100644 (file)
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -111,3 +111,4 @@ obj-$(CONFIG_BATTERY_SURFACE)       += surface_battery.o
 obj-$(CONFIG_CHARGER_SURFACE)  += surface_charger.o
 obj-$(CONFIG_BATTERY_UG3105)   += ug3105_battery.o
 obj-$(CONFIG_CHARGER_QCOM_SMB2)        += qcom_pmi8998_charger.o
+obj-$(CONFIG_FUEL_GAUGE_MM8013)        += mm8013.o

diff --git a/drivers/power/supply/mm8013.c b/drivers/power/supply/mm8013.c
new file mode 100644 (file)
index 0000000..bd8d54d
--- /dev/null
+++ b/drivers/power/supply/mm8013.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2023, Linaro Limited
+ */
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+
+#define REG_BATID                      0x00 /* This one is very unclear */
+ #define BATID_101                     0x0101 /* 107kOhm */
+ #define BATID_102                     0x0102 /* 10kOhm */
+#define REG_TEMPERATURE                        0x06
+#define REG_VOLTAGE                    0x08
+#define REG_FLAGS                      0x0a
+ #define MM8013_FLAG_OTC               BIT(15)
+ #define MM8013_FLAG_OTD               BIT(14)
+ #define MM8013_FLAG_BATHI             BIT(13)
+ #define MM8013_FLAG_FC                        BIT(9)
+ #define MM8013_FLAG_CHG               BIT(8)
+ #define MM8013_FLAG_DSG               BIT(0)
+#define REG_FULL_CHARGE_CAPACITY       0x0e
+#define REG_AVERAGE_CURRENT            0x14
+#define REG_AVERAGE_TIME_TO_EMPTY      0x16
+#define REG_AVERAGE_TIME_TO_FULL       0x18
+#define REG_CYCLE_COUNT                        0x2a
+#define REG_STATE_OF_CHARGE            0x2c
+#define REG_DESIGN_CAPACITY            0x3c
+/* TODO: 0x62-0x68 seem to contain 'MM8013C' in a length-prefixed, non-terminated string */
+
+#define DECIKELVIN_TO_DECIDEGC(t)      (t - 2731)
+
+struct mm8013_chip {
+       struct i2c_client *client;
+       struct regmap *regmap;
+};
+
+static int mm8013_checkdevice(struct mm8013_chip *chip)
+{
+       int battery_id, ret;
+       u32 val;
+
+       ret = regmap_write(chip->regmap, REG_BATID, 0x0008);
+       if (ret < 0)
+               return ret;
+
+       regmap_read(chip->regmap, REG_BATID, &val);
+       if (ret < 0)
+               return ret;
+
+       if (val == BATID_102)
+               battery_id = 2;
+       else if (val == BATID_101)
+               battery_id = 1;
+       else
+               return -EINVAL;
+
+       dev_dbg(&chip->client->dev, "battery_id: %d\n", battery_id);
+
+       return 0;
+}
+
+static enum power_supply_property mm8013_battery_props[] = {
+       POWER_SUPPLY_PROP_CAPACITY,
+       POWER_SUPPLY_PROP_CHARGE_FULL,
+       POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+       POWER_SUPPLY_PROP_CURRENT_NOW,
+       POWER_SUPPLY_PROP_CYCLE_COUNT,
+       POWER_SUPPLY_PROP_HEALTH,
+       POWER_SUPPLY_PROP_PRESENT,
+       POWER_SUPPLY_PROP_STATUS,
+       POWER_SUPPLY_PROP_TEMP,
+       POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
+       POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
+       POWER_SUPPLY_PROP_VOLTAGE_NOW,
+};
+
+static int mm8013_get_property(struct power_supply *psy,
+                              enum power_supply_property psp,
+                              union power_supply_propval *val)
+{
+       struct mm8013_chip *chip = psy->drv_data;
+       int ret = 0;
+       u32 regval;
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_CAPACITY:
+               ret = regmap_read(chip->regmap, REG_STATE_OF_CHARGE, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = regval;
+               break;
+       case POWER_SUPPLY_PROP_CHARGE_FULL:
+               ret = regmap_read(chip->regmap, REG_FULL_CHARGE_CAPACITY, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = 1000 * regval;
+               break;
+       case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+               ret = regmap_read(chip->regmap, REG_DESIGN_CAPACITY, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = 1000 * regval;
+               break;
+       case POWER_SUPPLY_PROP_CURRENT_NOW:
+               ret = regmap_read(chip->regmap, REG_AVERAGE_CURRENT, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = -1000 * (s16)regval;
+               break;
+       case POWER_SUPPLY_PROP_CYCLE_COUNT:
+               ret = regmap_read(chip->regmap, REG_CYCLE_COUNT, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = regval;
+               break;
+       case POWER_SUPPLY_PROP_HEALTH:
+               ret = regmap_read(chip->regmap, REG_FLAGS, &regval);
+               if (ret < 0)
+                       return ret;
+
+               if (regval & MM8013_FLAG_BATHI)
+                       val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+               else if (regval & (MM8013_FLAG_OTD | MM8013_FLAG_OTC))
+                       val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+               else
+                       val->intval = POWER_SUPPLY_HEALTH_GOOD;
+               break;
+       case POWER_SUPPLY_PROP_PRESENT:
+               ret = regmap_read(chip->regmap, REG_TEMPERATURE, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = ((s16)regval > 0);
+               break;
+       case POWER_SUPPLY_PROP_STATUS:
+               ret = regmap_read(chip->regmap, REG_FLAGS, &regval);
+               if (ret < 0)
+                       return ret;
+
+               if (regval & MM8013_FLAG_DSG)
+                       val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+               else if (regval & MM8013_FLAG_CHG)
+                       val->intval = POWER_SUPPLY_STATUS_CHARGING;
+               else if (regval & MM8013_FLAG_FC)
+                       val->intval = POWER_SUPPLY_STATUS_FULL;
+               else
+                       val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+               break;
+       case POWER_SUPPLY_PROP_TEMP:
+               ret = regmap_read(chip->regmap, REG_TEMPERATURE, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = DECIKELVIN_TO_DECIDEGC(regval);
+               break;
+       case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
+               ret = regmap_read(chip->regmap, REG_AVERAGE_TIME_TO_EMPTY, &regval);
+               if (ret < 0)
+                       return ret;
+
+               /* The estimation is not yet ready */
+               if (regval == U16_MAX)
+                       return -ENODATA;
+
+               val->intval = regval;
+               break;
+       case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
+               ret = regmap_read(chip->regmap, REG_AVERAGE_TIME_TO_FULL, &regval);
+               if (ret < 0)
+                       return ret;
+
+               /* The estimation is not yet ready */
+               if (regval == U16_MAX)
+                       return -ENODATA;
+
+               val->intval = regval;
+               break;
+       case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+               ret = regmap_read(chip->regmap, REG_VOLTAGE, &regval);
+               if (ret < 0)
+                       return ret;
+
+               val->intval = 1000 * regval;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static const struct power_supply_desc mm8013_desc = {
+       .name                   = "mm8013",
+       .type                   = POWER_SUPPLY_TYPE_BATTERY,
+       .properties             = mm8013_battery_props,
+       .num_properties         = ARRAY_SIZE(mm8013_battery_props),
+       .get_property           = mm8013_get_property,
+};
+
+static const struct regmap_config mm8013_regmap_config = {
+       .reg_bits = 8,
+       .val_bits = 16,
+       .max_register = 0x68,
+       .use_single_read = true,
+       .use_single_write = true,
+       .val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int mm8013_probe(struct i2c_client *client)
+{
+       struct power_supply_config psy_cfg = {};
+       struct device *dev = &client->dev;
+       struct power_supply *psy;
+       struct mm8013_chip *chip;
+       int ret = 0;
+
+       if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+               return dev_err_probe(dev, -EIO,
+                                    "I2C_FUNC_SMBUS_WORD_DATA not supported\n");
+
+       chip = devm_kzalloc(dev, sizeof(struct mm8013_chip), GFP_KERNEL);
+       if (!chip)
+               return -ENOMEM;
+
+       chip->client = client;
+
+       chip->regmap = devm_regmap_init_i2c(client, &mm8013_regmap_config);
+       if (IS_ERR(chip->regmap))
+               return dev_err_probe(dev, ret, "Couldn't initialize regmap\n");
+
+       ret = mm8013_checkdevice(chip);
+       if (ret)
+               return dev_err_probe(dev, ret, "MM8013 not found\n");
+
+       psy_cfg.drv_data = chip;
+       psy_cfg.of_node = dev->of_node;
+
+       psy = devm_power_supply_register(dev, &mm8013_desc, &psy_cfg);
+       if (IS_ERR(psy))
+               return PTR_ERR(psy);
+
+       return 0;
+}
+
+static const struct i2c_device_id mm8013_id_table[] = {
+       { "mm8013", 0 },
+       {}
+};
+MODULE_DEVICE_TABLE(i2c, mm8013_id_table);
+
+static const struct of_device_id mm8013_match_table[] = {
+       { .compatible = "mitsumi,mm8013" },
+       {}
+};
+
+static struct i2c_driver mm8013_i2c_driver = {
+       .probe = mm8013_probe,
+       .id_table = mm8013_id_table,
+       .driver = {
+               .name = "mm8013",
+               .of_match_table = mm8013_match_table,
+       },
+};
+module_i2c_driver(mm8013_i2c_driver);
+
+MODULE_DESCRIPTION("MM8013 fuel gauge driver");
+MODULE_LICENSE("GPL");