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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2023, Nikita Travkin <nikita@trvn.ru>
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/timekeeping.h>
#include <linux/mod_devicetable.h>
#define PM8916_PERPH_TYPE 0x04
#define PM8916_BMS_VM_TYPE 0x020D
#define PM8916_SEC_ACCESS 0xD0
#define PM8916_SEC_MAGIC 0xA5
#define PM8916_BMS_VM_STATUS1 0x08
#define PM8916_BMS_VM_FSM_STATE(x) (((x) & 0b00111000) >> 3)
#define PM8916_BMS_VM_FSM_STATE_S2 0x2
#define PM8916_BMS_VM_MODE_CTL 0x40
#define PM8916_BMS_VM_MODE_FORCE_S3 (BIT(0) | BIT(1))
#define PM8916_BMS_VM_MODE_NORMAL (BIT(1) | BIT(3))
#define PM8916_BMS_VM_EN_CTL 0x46
#define PM8916_BMS_ENABLED BIT(7)
#define PM8916_BMS_VM_FIFO_LENGTH_CTL 0x47
#define PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL 0x55
#define PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL 0x56
#define PM8916_BMS_VM_S3_S7_OCV_DATA0 0x6A
#define PM8916_BMS_VM_BMS_FIFO_REG_0_LSB 0xC0
/* Using only 1 fifo is broken in hardware */
#define PM8916_BMS_VM_FIFO_COUNT 2 /* 2 .. 8 */
#define PM8916_BMS_VM_S1_SAMPLE_INTERVAL 10
#define PM8916_BMS_VM_S2_SAMPLE_INTERVAL 10
struct pm8916_bms_vm_battery {
struct device *dev;
struct power_supply *battery;
struct power_supply_battery_info *info;
struct regmap *regmap;
unsigned int reg;
unsigned int last_ocv;
time64_t last_ocv_time;
unsigned int vbat_now;
};
static int pm8916_bms_vm_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct pm8916_bms_vm_battery *bat = power_supply_get_drvdata(psy);
struct power_supply_battery_info *info = bat->info;
int supplied;
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
supplied = power_supply_am_i_supplied(psy);
if (supplied < 0 && supplied != -ENODEV)
return supplied;
else if (supplied && supplied != -ENODEV)
val->intval = POWER_SUPPLY_STATUS_CHARGING;
else
val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
return 0;
case POWER_SUPPLY_PROP_HEALTH:
if (bat->vbat_now < info->voltage_min_design_uv)
val->intval = POWER_SUPPLY_HEALTH_DEAD;
else if (bat->vbat_now > info->voltage_max_design_uv)
val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
else
val->intval = POWER_SUPPLY_HEALTH_GOOD;
return 0;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
val->intval = bat->vbat_now;
return 0;
case POWER_SUPPLY_PROP_VOLTAGE_OCV:
/*
* Hardware only reliably measures OCV when the system is off or suspended.
* We expose the last known OCV value on boot, invalidating it after 180 seconds.
*/
if (ktime_get_seconds() - bat->last_ocv_time > 180)
return -ENODATA;
val->intval = bat->last_ocv;
return 0;
default:
return -EINVAL;
}
}
static enum power_supply_property pm8916_bms_vm_battery_properties[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_VOLTAGE_OCV,
POWER_SUPPLY_PROP_HEALTH,
};
static irqreturn_t pm8916_bms_vm_fifo_update_done_irq(int irq, void *data)
{
struct pm8916_bms_vm_battery *bat = data;
u16 vbat_data[PM8916_BMS_VM_FIFO_COUNT];
int ret;
ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_BMS_VM_BMS_FIFO_REG_0_LSB,
&vbat_data, PM8916_BMS_VM_FIFO_COUNT * 2);
if (ret)
return IRQ_HANDLED;
/*
* The VM-BMS hardware only collects voltage data and the software
* has to process it to calculate the OCV and SoC. Hardware provides
* up to 8 averaged measurements for software to take in account.
*
* Just use the last measured value for now to report the current
* battery voltage.
*/
bat->vbat_now = vbat_data[PM8916_BMS_VM_FIFO_COUNT - 1] * 300;
power_supply_changed(bat->battery);
return IRQ_HANDLED;
}
static const struct power_supply_desc pm8916_bms_vm_battery_psy_desc = {
.name = "pm8916-bms-vm",
.type = POWER_SUPPLY_TYPE_BATTERY,
.properties = pm8916_bms_vm_battery_properties,
.num_properties = ARRAY_SIZE(pm8916_bms_vm_battery_properties),
.get_property = pm8916_bms_vm_battery_get_property,
};
static int pm8916_bms_vm_battery_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct pm8916_bms_vm_battery *bat;
struct power_supply_config psy_cfg = {};
int ret, irq;
unsigned int tmp;
bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);
if (!bat)
return -ENOMEM;
bat->dev = dev;
bat->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!bat->regmap)
return -ENODEV;
ret = device_property_read_u32(dev, "reg", &bat->reg);
if (ret < 0)
return -EINVAL;
irq = platform_get_irq_byname(pdev, "fifo");
if (irq < 0)
return irq;
ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_bms_vm_fifo_update_done_irq,
IRQF_ONESHOT, "pm8916_vm_bms", bat);
if (ret)
return ret;
ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_PERPH_TYPE, &tmp, 2);
if (ret)
goto comm_error;
if (tmp != PM8916_BMS_VM_TYPE)
return dev_err_probe(dev, -ENODEV, "Device reported wrong type: 0x%X\n", tmp);
ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL,
PM8916_BMS_VM_S1_SAMPLE_INTERVAL);
if (ret)
goto comm_error;
ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL,
PM8916_BMS_VM_S2_SAMPLE_INTERVAL);
if (ret)
goto comm_error;
ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_FIFO_LENGTH_CTL,
PM8916_BMS_VM_FIFO_COUNT << 4 | PM8916_BMS_VM_FIFO_COUNT);
if (ret)
goto comm_error;
ret = regmap_write(bat->regmap,
bat->reg + PM8916_BMS_VM_EN_CTL, PM8916_BMS_ENABLED);
if (ret)
goto comm_error;
ret = regmap_bulk_read(bat->regmap,
bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
if (ret)
goto comm_error;
bat->last_ocv_time = ktime_get_seconds();
bat->last_ocv = tmp * 300;
bat->vbat_now = bat->last_ocv;
psy_cfg.drv_data = bat;
psy_cfg.of_node = dev->of_node;
bat->battery = devm_power_supply_register(dev, &pm8916_bms_vm_battery_psy_desc, &psy_cfg);
if (IS_ERR(bat->battery))
return dev_err_probe(dev, PTR_ERR(bat->battery), "Unable to register battery\n");
ret = power_supply_get_battery_info(bat->battery, &bat->info);
if (ret)
return dev_err_probe(dev, ret, "Unable to get battery info\n");
platform_set_drvdata(pdev, bat);
return 0;
comm_error:
return dev_err_probe(dev, ret, "Unable to communicate with device\n");
}
static int pm8916_bms_vm_battery_suspend(struct platform_device *pdev, pm_message_t state)
{
struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
int ret;
/*
* Due to a hardware quirk the FSM doesn't switch states normally.
* Instead we unlock the debug registers and force S3 (Measure OCV/Sleep)
* mode every time we suspend.
*/
ret = regmap_write(bat->regmap,
bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
if (ret)
goto error;
ret = regmap_write(bat->regmap,
bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_FORCE_S3);
if (ret)
goto error;
return 0;
error:
dev_err(bat->dev, "Failed to force S3 mode: %pe\n", ERR_PTR(ret));
return ret;
}
static int pm8916_bms_vm_battery_resume(struct platform_device *pdev)
{
struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
int ret;
unsigned int tmp;
ret = regmap_bulk_read(bat->regmap,
bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
bat->last_ocv_time = ktime_get_seconds();
bat->last_ocv = tmp * 300;
ret = regmap_write(bat->regmap,
bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
if (ret)
goto error;
ret = regmap_write(bat->regmap,
bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_NORMAL);
if (ret)
goto error;
return 0;
error:
dev_err(bat->dev, "Failed to return normal mode: %pe\n", ERR_PTR(ret));
return ret;
}
static const struct of_device_id pm8916_bms_vm_battery_of_match[] = {
{ .compatible = "qcom,pm8916-bms-vm", },
{}
};
MODULE_DEVICE_TABLE(of, pm8916_bms_vm_battery_of_match);
static struct platform_driver pm8916_bms_vm_battery_driver = {
.driver = {
.name = "pm8916-bms-vm",
.of_match_table = pm8916_bms_vm_battery_of_match,
},
.probe = pm8916_bms_vm_battery_probe,
.suspend = pm8916_bms_vm_battery_suspend,
.resume = pm8916_bms_vm_battery_resume,
};
module_platform_driver(pm8916_bms_vm_battery_driver);
MODULE_DESCRIPTION("pm8916 BMS-VM driver");
MODULE_AUTHOR("Nikita Travkin <nikita@trvn.ru>");
MODULE_LICENSE("GPL");
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