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f059b46e6f
Add a new battery driver for the uPI uG3105 battery monitor. Note the uG3105 is not a full-featured autonomous fuel-gauge. Instead it is expected to be use in combination with some always on microcontroller reading its coulomb-counter before it can wrap (must be read every 400 seconds!). Since Linux does not monitor coulomb-counter changes while the device is off or suspended, the coulomb counter is not used atm. So far this driver is only used on x86/ACPI (non devicetree) devs (also note there is no of_match table). Therefor there is no devicetree bindings documentation for this driver's "upisemi,rsns-microohm" property since this is not used in actual devicetree files and the dt bindings maintainers have requested properties with no actual dt users to _not_ be added to the dt bindings. The property's name has been chosen so that it should not need to be changed if/when devicetree enumeration support gets added later, as it mirrors "maxim,rsns-microohm" from the "maxim,max17042" bindings. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
487 lines
13 KiB
C
487 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Battery monitor driver for the uPI uG3105 battery monitor
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*
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* Note the uG3105 is not a full-featured autonomous fuel-gauge. Instead it is
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* expected to be use in combination with some always on microcontroller reading
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* its coulomb-counter before it can wrap (must be read every 400 seconds!).
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*
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* Since Linux does not monitor coulomb-counter changes while the device
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* is off or suspended, the coulomb counter is not used atm.
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*
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* Possible improvements:
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* 1. Activate commented out total_coulomb_count code
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* 2. Reset total_coulomb_count val to 0 when the battery is as good as empty
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* and remember that we did this (and clear the flag for this on susp/resume)
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* 3. When the battery is full check if the flag that we set total_coulomb_count
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* to when the battery was empty is set. If so we now know the capacity,
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* not the design, but actual capacity, of the battery
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* 4. Add some mechanism (needs userspace help, or maybe use efivar?) to remember
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* the actual capacity of the battery over reboots
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* 5. When we know the actual capacity at probe time, add energy_now and
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* energy_full attributes. Guess boot + resume energy_now value based on ocv
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* and then use total_coulomb_count to report energy_now over time, resetting
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* things to adjust for drift when empty/full. This should give more accurate
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* readings, esp. in the 30-70% range and allow userspace to estimate time
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* remaining till empty/full
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* 6. Maybe unregister + reregister the psy device when we learn the actual
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* capacity during run-time ?
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*
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* The above will also require some sort of mwh_per_unit calculation. Testing
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* has shown that an estimated 7404mWh increase of the battery's energy results
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* in a total_coulomb_count increase of 3277 units with a 5 milli-ohm sense R.
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*
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* Copyright (C) 2021 Hans de Goede <hdegoede@redhat.com>
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*/
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#include <linux/devm-helpers.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/mod_devicetable.h>
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#include <linux/power_supply.h>
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#include <linux/workqueue.h>
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#define UG3105_MOV_AVG_WINDOW 8
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#define UG3105_INIT_POLL_TIME (5 * HZ)
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#define UG3105_POLL_TIME (30 * HZ)
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#define UG3105_SETTLE_TIME (1 * HZ)
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#define UG3105_INIT_POLL_COUNT 30
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#define UG3105_REG_MODE 0x00
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#define UG3105_REG_CTRL1 0x01
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#define UG3105_REG_COULOMB_CNT 0x02
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#define UG3105_REG_BAT_VOLT 0x08
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#define UG3105_REG_BAT_CURR 0x0c
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#define UG3105_MODE_STANDBY 0x00
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#define UG3105_MODE_RUN 0x10
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#define UG3105_CTRL1_RESET_COULOMB_CNT 0x03
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#define UG3105_CURR_HYST_UA 65000
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#define UG3105_LOW_BAT_UV 3700000
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#define UG3105_FULL_BAT_HYST_UV 38000
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struct ug3105_chip {
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struct i2c_client *client;
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struct power_supply *psy;
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struct power_supply_battery_info *info;
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struct delayed_work work;
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struct mutex lock;
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int ocv[UG3105_MOV_AVG_WINDOW]; /* micro-volt */
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int intern_res[UG3105_MOV_AVG_WINDOW]; /* milli-ohm */
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int poll_count;
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int ocv_avg_index;
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int ocv_avg; /* micro-volt */
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int intern_res_poll_count;
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int intern_res_avg_index;
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int intern_res_avg; /* milli-ohm */
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int volt; /* micro-volt */
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int curr; /* micro-ampere */
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int total_coulomb_count;
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int uv_per_unit;
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int ua_per_unit;
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int status;
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int capacity;
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bool supplied;
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};
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static int ug3105_read_word(struct i2c_client *client, u8 reg)
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{
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int val;
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val = i2c_smbus_read_word_data(client, reg);
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if (val < 0)
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dev_err(&client->dev, "Error reading reg 0x%02x\n", reg);
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return val;
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}
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static int ug3105_get_status(struct ug3105_chip *chip)
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{
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int full = chip->info->constant_charge_voltage_max_uv - UG3105_FULL_BAT_HYST_UV;
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if (chip->curr > UG3105_CURR_HYST_UA)
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return POWER_SUPPLY_STATUS_CHARGING;
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if (chip->curr < -UG3105_CURR_HYST_UA)
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return POWER_SUPPLY_STATUS_DISCHARGING;
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if (chip->supplied && chip->ocv_avg > full)
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return POWER_SUPPLY_STATUS_FULL;
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return POWER_SUPPLY_STATUS_NOT_CHARGING;
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}
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static int ug3105_get_capacity(struct ug3105_chip *chip)
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{
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/*
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* OCV voltages in uV for 0-110% in 5% increments, the 100-110% is
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* for LiPo HV (High-Voltage) bateries which can go up to 4.35V
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* instead of the usual 4.2V.
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*/
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static const int ocv_capacity_tbl[23] = {
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3350000,
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3610000,
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3690000,
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3710000,
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3730000,
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3750000,
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3770000,
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3786667,
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3803333,
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3820000,
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3836667,
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3853333,
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3870000,
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3907500,
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3945000,
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3982500,
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4020000,
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4075000,
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4110000,
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4150000,
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4200000,
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4250000,
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4300000,
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};
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int i, ocv_diff, ocv_step;
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if (chip->ocv_avg < ocv_capacity_tbl[0])
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return 0;
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if (chip->status == POWER_SUPPLY_STATUS_FULL)
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return 100;
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for (i = 1; i < ARRAY_SIZE(ocv_capacity_tbl); i++) {
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if (chip->ocv_avg > ocv_capacity_tbl[i])
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continue;
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ocv_diff = ocv_capacity_tbl[i] - chip->ocv_avg;
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ocv_step = ocv_capacity_tbl[i] - ocv_capacity_tbl[i - 1];
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/* scale 0-110% down to 0-100% for LiPo HV */
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if (chip->info->constant_charge_voltage_max_uv >= 4300000)
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return (i * 500 - ocv_diff * 500 / ocv_step) / 110;
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else
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return i * 5 - ocv_diff * 5 / ocv_step;
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}
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return 100;
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}
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static void ug3105_work(struct work_struct *work)
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{
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struct ug3105_chip *chip = container_of(work, struct ug3105_chip,
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work.work);
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int i, val, curr_diff, volt_diff, res, win_size;
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bool prev_supplied = chip->supplied;
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int prev_status = chip->status;
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int prev_volt = chip->volt;
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int prev_curr = chip->curr;
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struct power_supply *psy;
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mutex_lock(&chip->lock);
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psy = chip->psy;
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if (!psy)
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goto out;
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val = ug3105_read_word(chip->client, UG3105_REG_BAT_VOLT);
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if (val < 0)
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goto out;
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chip->volt = val * chip->uv_per_unit;
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val = ug3105_read_word(chip->client, UG3105_REG_BAT_CURR);
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if (val < 0)
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goto out;
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chip->curr = (s16)val * chip->ua_per_unit;
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chip->ocv[chip->ocv_avg_index] =
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chip->volt - chip->curr * chip->intern_res_avg / 1000;
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chip->ocv_avg_index = (chip->ocv_avg_index + 1) % UG3105_MOV_AVG_WINDOW;
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chip->poll_count++;
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/*
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* See possible improvements comment above.
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*
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* Read + reset coulomb counter every 10 polls (every 300 seconds)
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* if ((chip->poll_count % 10) == 0) {
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* val = ug3105_read_word(chip->client, UG3105_REG_COULOMB_CNT);
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* if (val < 0)
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* goto out;
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*
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* i2c_smbus_write_byte_data(chip->client, UG3105_REG_CTRL1,
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* UG3105_CTRL1_RESET_COULOMB_CNT);
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*
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* chip->total_coulomb_count += (s16)val;
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* dev_dbg(&chip->client->dev, "coulomb count %d total %d\n",
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* (s16)val, chip->total_coulomb_count);
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* }
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*/
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chip->ocv_avg = 0;
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win_size = min(chip->poll_count, UG3105_MOV_AVG_WINDOW);
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for (i = 0; i < win_size; i++)
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chip->ocv_avg += chip->ocv[i];
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chip->ocv_avg /= win_size;
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chip->supplied = power_supply_am_i_supplied(psy);
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chip->status = ug3105_get_status(chip);
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chip->capacity = ug3105_get_capacity(chip);
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/*
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* Skip internal resistance calc on charger [un]plug and
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* when the battery is almost empty (voltage low).
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*/
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if (chip->supplied != prev_supplied ||
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chip->volt < UG3105_LOW_BAT_UV ||
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chip->poll_count < 2)
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goto out;
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/*
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* Assuming that the OCV voltage does not change significantly
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* between 2 polls, then we can calculate the internal resistance
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* on a significant current change by attributing all voltage
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* change between the 2 readings to the internal resistance.
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*/
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curr_diff = abs(chip->curr - prev_curr);
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if (curr_diff < UG3105_CURR_HYST_UA)
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goto out;
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volt_diff = abs(chip->volt - prev_volt);
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res = volt_diff * 1000 / curr_diff;
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if ((res < (chip->intern_res_avg * 2 / 3)) ||
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(res > (chip->intern_res_avg * 4 / 3))) {
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dev_dbg(&chip->client->dev, "Ignoring outlier internal resistance %d mOhm\n", res);
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goto out;
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}
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dev_dbg(&chip->client->dev, "Internal resistance %d mOhm\n", res);
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chip->intern_res[chip->intern_res_avg_index] = res;
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chip->intern_res_avg_index = (chip->intern_res_avg_index + 1) % UG3105_MOV_AVG_WINDOW;
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chip->intern_res_poll_count++;
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chip->intern_res_avg = 0;
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win_size = min(chip->intern_res_poll_count, UG3105_MOV_AVG_WINDOW);
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for (i = 0; i < win_size; i++)
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chip->intern_res_avg += chip->intern_res[i];
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chip->intern_res_avg /= win_size;
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out:
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mutex_unlock(&chip->lock);
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queue_delayed_work(system_wq, &chip->work,
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(chip->poll_count <= UG3105_INIT_POLL_COUNT) ?
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UG3105_INIT_POLL_TIME : UG3105_POLL_TIME);
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if (chip->status != prev_status && psy)
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power_supply_changed(psy);
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}
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static enum power_supply_property ug3105_battery_props[] = {
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POWER_SUPPLY_PROP_STATUS,
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POWER_SUPPLY_PROP_PRESENT,
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POWER_SUPPLY_PROP_TECHNOLOGY,
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POWER_SUPPLY_PROP_SCOPE,
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POWER_SUPPLY_PROP_VOLTAGE_NOW,
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POWER_SUPPLY_PROP_VOLTAGE_OCV,
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POWER_SUPPLY_PROP_CURRENT_NOW,
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POWER_SUPPLY_PROP_CAPACITY,
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};
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static int ug3105_get_property(struct power_supply *psy,
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enum power_supply_property psp,
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union power_supply_propval *val)
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{
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struct ug3105_chip *chip = power_supply_get_drvdata(psy);
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int ret = 0;
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mutex_lock(&chip->lock);
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if (!chip->psy) {
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ret = -EAGAIN;
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goto out;
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}
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switch (psp) {
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case POWER_SUPPLY_PROP_STATUS:
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val->intval = chip->status;
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break;
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case POWER_SUPPLY_PROP_PRESENT:
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val->intval = 1;
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break;
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case POWER_SUPPLY_PROP_TECHNOLOGY:
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val->intval = chip->info->technology;
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break;
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case POWER_SUPPLY_PROP_SCOPE:
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val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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ret = ug3105_read_word(chip->client, UG3105_REG_BAT_VOLT);
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if (ret < 0)
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break;
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val->intval = ret * chip->uv_per_unit;
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ret = 0;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_OCV:
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val->intval = chip->ocv_avg;
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break;
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case POWER_SUPPLY_PROP_CURRENT_NOW:
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ret = ug3105_read_word(chip->client, UG3105_REG_BAT_CURR);
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if (ret < 0)
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break;
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val->intval = (s16)ret * chip->ua_per_unit;
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ret = 0;
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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val->intval = chip->capacity;
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break;
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default:
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ret = -EINVAL;
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}
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out:
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mutex_unlock(&chip->lock);
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return ret;
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}
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static void ug3105_external_power_changed(struct power_supply *psy)
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{
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struct ug3105_chip *chip = power_supply_get_drvdata(psy);
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dev_dbg(&chip->client->dev, "external power changed\n");
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mod_delayed_work(system_wq, &chip->work, UG3105_SETTLE_TIME);
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}
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static const struct power_supply_desc ug3105_psy_desc = {
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.name = "ug3105_battery",
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.type = POWER_SUPPLY_TYPE_BATTERY,
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.get_property = ug3105_get_property,
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.external_power_changed = ug3105_external_power_changed,
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.properties = ug3105_battery_props,
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.num_properties = ARRAY_SIZE(ug3105_battery_props),
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};
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static void ug3105_init(struct ug3105_chip *chip)
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{
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chip->poll_count = 0;
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chip->ocv_avg_index = 0;
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chip->total_coulomb_count = 0;
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i2c_smbus_write_byte_data(chip->client, UG3105_REG_MODE,
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UG3105_MODE_RUN);
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i2c_smbus_write_byte_data(chip->client, UG3105_REG_CTRL1,
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UG3105_CTRL1_RESET_COULOMB_CNT);
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queue_delayed_work(system_wq, &chip->work, 0);
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flush_delayed_work(&chip->work);
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}
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static int ug3105_probe(struct i2c_client *client)
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{
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struct power_supply_config psy_cfg = {};
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struct device *dev = &client->dev;
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u32 curr_sense_res_uohm = 10000;
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struct power_supply *psy;
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struct ug3105_chip *chip;
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int ret;
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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chip->client = client;
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mutex_init(&chip->lock);
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ret = devm_delayed_work_autocancel(dev, &chip->work, ug3105_work);
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if (ret)
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return ret;
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psy_cfg.drv_data = chip;
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psy = devm_power_supply_register(dev, &ug3105_psy_desc, &psy_cfg);
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if (IS_ERR(psy))
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return PTR_ERR(psy);
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ret = power_supply_get_battery_info(psy, &chip->info);
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if (ret)
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return ret;
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if (chip->info->factory_internal_resistance_uohm == -EINVAL ||
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chip->info->constant_charge_voltage_max_uv == -EINVAL) {
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dev_err(dev, "error required properties are missing\n");
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return -ENODEV;
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}
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device_property_read_u32(dev, "upisemi,rsns-microohm", &curr_sense_res_uohm);
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/*
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* DAC maximum is 4.5V divided by 65536 steps + an unknown factor of 10
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* coming from somewhere for some reason (verified with a volt-meter).
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*/
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chip->uv_per_unit = 45000000/65536;
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/* Datasheet says 8.1 uV per unit for the current ADC */
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chip->ua_per_unit = 8100000 / curr_sense_res_uohm;
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/* Use provided internal resistance as start point (in milli-ohm) */
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chip->intern_res_avg = chip->info->factory_internal_resistance_uohm / 1000;
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/* Also add it to the internal resistance moving average window */
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chip->intern_res[0] = chip->intern_res_avg;
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chip->intern_res_avg_index = 1;
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chip->intern_res_poll_count = 1;
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mutex_lock(&chip->lock);
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chip->psy = psy;
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mutex_unlock(&chip->lock);
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ug3105_init(chip);
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i2c_set_clientdata(client, chip);
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return 0;
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}
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static int __maybe_unused ug3105_suspend(struct device *dev)
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{
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struct ug3105_chip *chip = dev_get_drvdata(dev);
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cancel_delayed_work_sync(&chip->work);
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i2c_smbus_write_byte_data(chip->client, UG3105_REG_MODE,
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|
UG3105_MODE_STANDBY);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __maybe_unused ug3105_resume(struct device *dev)
|
|
{
|
|
struct ug3105_chip *chip = dev_get_drvdata(dev);
|
|
|
|
ug3105_init(chip);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static SIMPLE_DEV_PM_OPS(ug3105_pm_ops, ug3105_suspend,
|
|
ug3105_resume);
|
|
|
|
static const struct i2c_device_id ug3105_id[] = {
|
|
{ "ug3105" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, ug3105_id);
|
|
|
|
static struct i2c_driver ug3105_i2c_driver = {
|
|
.driver = {
|
|
.name = "ug3105",
|
|
.pm = &ug3105_pm_ops,
|
|
},
|
|
.probe_new = ug3105_probe,
|
|
.id_table = ug3105_id,
|
|
};
|
|
module_i2c_driver(ug3105_i2c_driver);
|
|
|
|
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
|
|
MODULE_DESCRIPTION("uPI uG3105 battery monitor driver");
|
|
MODULE_LICENSE("GPL");
|