drivers/power/supply/pm8916_bms_vm.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2023, Nikita Travkin <nikita@trvn.ru>
   4  */
   5
   6 #include <linux/errno.h>
   7 #include <linux/module.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/power_supply.h>
  10 #include <linux/property.h>
  11 #include <linux/regmap.h>
  12 #include <linux/slab.h>
  13 #include <linux/delay.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/timekeeping.h>
  16 #include <linux/mod_devicetable.h>
  17
  18 #define PM8916_PERPH_TYPE 0x04
  19 #define PM8916_BMS_VM_TYPE 0x020D
  20
  21 #define PM8916_SEC_ACCESS 0xD0
  22 #define PM8916_SEC_MAGIC 0xA5
  23
  24 #define PM8916_BMS_VM_STATUS1 0x08
  25 #define PM8916_BMS_VM_FSM_STATE(x) (((x) & 0b00111000) >> 3)
  26 #define PM8916_BMS_VM_FSM_STATE_S2 0x2
  27
  28 #define PM8916_BMS_VM_MODE_CTL 0x40
  29 #define PM8916_BMS_VM_MODE_FORCE_S3 (BIT(0) | BIT(1))
  30 #define PM8916_BMS_VM_MODE_NORMAL (BIT(1) | BIT(3))
  31
  32 #define PM8916_BMS_VM_EN_CTL 0x46
  33 #define PM8916_BMS_ENABLED BIT(7)
  34
  35 #define PM8916_BMS_VM_FIFO_LENGTH_CTL 0x47
  36 #define PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL 0x55
  37 #define PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL 0x56
  38 #define PM8916_BMS_VM_S3_S7_OCV_DATA0 0x6A
  39 #define PM8916_BMS_VM_BMS_FIFO_REG_0_LSB 0xC0
  40
  41 /* Using only 1 fifo is broken in hardware */
  42 #define PM8916_BMS_VM_FIFO_COUNT 2 /* 2 .. 8 */
  43
  44 #define PM8916_BMS_VM_S1_SAMPLE_INTERVAL 10
  45 #define PM8916_BMS_VM_S2_SAMPLE_INTERVAL 10
  46
  47 struct pm8916_bms_vm_battery {
  48         struct device *dev;
  49         struct power_supply *battery;
  50         struct power_supply_battery_info *info;
  51         struct regmap *regmap;
  52         unsigned int reg;
  53         unsigned int last_ocv;
  54         time64_t last_ocv_time;
  55         unsigned int vbat_now;
  56 };
  57
  58 static int pm8916_bms_vm_battery_get_property(struct power_supply *psy,
  59                                               enum power_supply_property psp,
  60                                               union power_supply_propval *val)
  61 {
  62         struct pm8916_bms_vm_battery *bat = power_supply_get_drvdata(psy);
  63         struct power_supply_battery_info *info = bat->info;
  64         int supplied;
  65
  66         switch (psp) {
  67         case POWER_SUPPLY_PROP_STATUS:
  68                 supplied = power_supply_am_i_supplied(psy);
  69
  70                 if (supplied < 0 && supplied != -ENODEV)
  71                         return supplied;
  72                 else if (supplied && supplied != -ENODEV)
  73                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  74                 else
  75                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  76                 return 0;
  77
  78         case POWER_SUPPLY_PROP_HEALTH:
  79                 if (bat->vbat_now < info->voltage_min_design_uv)
  80                         val->intval = POWER_SUPPLY_HEALTH_DEAD;
  81                 else if (bat->vbat_now > info->voltage_max_design_uv)
  82                         val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
  83                 else
  84                         val->intval = POWER_SUPPLY_HEALTH_GOOD;
  85                 return 0;
  86
  87         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  88                 val->intval = bat->vbat_now;
  89                 return 0;
  90
  91         case POWER_SUPPLY_PROP_VOLTAGE_OCV:
  92                 /*
  93                  * Hardware only reliably measures OCV when the system is off or suspended.
  94                  * We expose the last known OCV value on boot, invalidating it after 180 seconds.
  95                  */
  96                 if (ktime_get_seconds() - bat->last_ocv_time > 180)
  97                         return -ENODATA;
  98
  99                 val->intval = bat->last_ocv;
 100                 return 0;
 101
 102         default:
 103                 return -EINVAL;
 104         }
 105 }
 106
 107 static enum power_supply_property pm8916_bms_vm_battery_properties[] = {
 108         POWER_SUPPLY_PROP_STATUS,
 109         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 110         POWER_SUPPLY_PROP_VOLTAGE_OCV,
 111         POWER_SUPPLY_PROP_HEALTH,
 112 };
 113
 114 static irqreturn_t pm8916_bms_vm_fifo_update_done_irq(int irq, void *data)
 115 {
 116         struct pm8916_bms_vm_battery *bat = data;
 117         u16 vbat_data[PM8916_BMS_VM_FIFO_COUNT];
 118         int ret;
 119
 120         ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_BMS_VM_BMS_FIFO_REG_0_LSB,
 121                                &vbat_data, PM8916_BMS_VM_FIFO_COUNT * 2);
 122         if (ret)
 123                 return IRQ_HANDLED;
 124
 125         /*
 126          * The VM-BMS hardware only collects voltage data and the software
 127          * has to process it to calculate the OCV and SoC. Hardware provides
 128          * up to 8 averaged measurements for software to take in account.
 129          *
 130          * Just use the last measured value for now to report the current
 131          * battery voltage.
 132          */
 133         bat->vbat_now = vbat_data[PM8916_BMS_VM_FIFO_COUNT - 1] * 300;
 134
 135         power_supply_changed(bat->battery);
 136
 137         return IRQ_HANDLED;
 138 }
 139
 140 static const struct power_supply_desc pm8916_bms_vm_battery_psy_desc = {
 141         .name = "pm8916-bms-vm",
 142         .type = POWER_SUPPLY_TYPE_BATTERY,
 143         .properties = pm8916_bms_vm_battery_properties,
 144         .num_properties = ARRAY_SIZE(pm8916_bms_vm_battery_properties),
 145         .get_property = pm8916_bms_vm_battery_get_property,
 146 };
 147
 148 static int pm8916_bms_vm_battery_probe(struct platform_device *pdev)
 149 {
 150         struct device *dev = &pdev->dev;
 151         struct pm8916_bms_vm_battery *bat;
 152         struct power_supply_config psy_cfg = {};
 153         int ret, irq;
 154         unsigned int tmp;
 155
 156         bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);
 157         if (!bat)
 158                 return -ENOMEM;
 159
 160         bat->dev = dev;
 161
 162         bat->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 163         if (!bat->regmap)
 164                 return -ENODEV;
 165
 166         ret = device_property_read_u32(dev, "reg", &bat->reg);
 167         if (ret < 0)
 168                 return -EINVAL;
 169
 170         irq = platform_get_irq_byname(pdev, "fifo");
 171         if (irq < 0)
 172                 return irq;
 173
 174         ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_bms_vm_fifo_update_done_irq,
 175                                         IRQF_ONESHOT, "pm8916_vm_bms", bat);
 176         if (ret)
 177                 return ret;
 178
 179         ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_PERPH_TYPE, &tmp, 2);
 180         if (ret)
 181                 goto comm_error;
 182
 183         if (tmp != PM8916_BMS_VM_TYPE)
 184                 return dev_err_probe(dev, -ENODEV, "Device reported wrong type: 0x%X\n", tmp);
 185
 186         ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL,
 187                            PM8916_BMS_VM_S1_SAMPLE_INTERVAL);
 188         if (ret)
 189                 goto comm_error;
 190         ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL,
 191                            PM8916_BMS_VM_S2_SAMPLE_INTERVAL);
 192         if (ret)
 193                 goto comm_error;
 194         ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_FIFO_LENGTH_CTL,
 195                            PM8916_BMS_VM_FIFO_COUNT << 4 | PM8916_BMS_VM_FIFO_COUNT);
 196         if (ret)
 197                 goto comm_error;
 198         ret = regmap_write(bat->regmap,
 199                            bat->reg + PM8916_BMS_VM_EN_CTL, PM8916_BMS_ENABLED);
 200         if (ret)
 201                 goto comm_error;
 202
 203         ret = regmap_bulk_read(bat->regmap,
 204                                bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
 205         if (ret)
 206                 goto comm_error;
 207
 208         bat->last_ocv_time = ktime_get_seconds();
 209         bat->last_ocv = tmp * 300;
 210         bat->vbat_now = bat->last_ocv;
 211
 212         psy_cfg.drv_data = bat;
 213         psy_cfg.of_node = dev->of_node;
 214
 215         bat->battery = devm_power_supply_register(dev, &pm8916_bms_vm_battery_psy_desc, &psy_cfg);
 216         if (IS_ERR(bat->battery))
 217                 return dev_err_probe(dev, PTR_ERR(bat->battery), "Unable to register battery\n");
 218
 219         ret = power_supply_get_battery_info(bat->battery, &bat->info);
 220         if (ret)
 221                 return dev_err_probe(dev, ret, "Unable to get battery info\n");
 222
 223         platform_set_drvdata(pdev, bat);
 224
 225         return 0;
 226
 227 comm_error:
 228         return dev_err_probe(dev, ret, "Unable to communicate with device\n");
 229 }
 230
 231 static int pm8916_bms_vm_battery_suspend(struct platform_device *pdev, pm_message_t state)
 232 {
 233         struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
 234         int ret;
 235
 236         /*
 237          * Due to a hardware quirk the FSM doesn't switch states normally.
 238          * Instead we unlock the debug registers and force S3 (Measure OCV/Sleep)
 239          * mode every time we suspend.
 240          */
 241
 242         ret = regmap_write(bat->regmap,
 243                            bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
 244         if (ret)
 245                 goto error;
 246         ret = regmap_write(bat->regmap,
 247                            bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_FORCE_S3);
 248         if (ret)
 249                 goto error;
 250
 251         return 0;
 252
 253 error:
 254         dev_err(bat->dev, "Failed to force S3 mode: %pe\n", ERR_PTR(ret));
 255         return ret;
 256 }
 257
 258 static int pm8916_bms_vm_battery_resume(struct platform_device *pdev)
 259 {
 260         struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
 261         int ret;
 262         unsigned int tmp;
 263
 264         ret = regmap_bulk_read(bat->regmap,
 265                                bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
 266
 267         bat->last_ocv_time = ktime_get_seconds();
 268         bat->last_ocv = tmp * 300;
 269
 270         ret = regmap_write(bat->regmap,
 271                            bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
 272         if (ret)
 273                 goto error;
 274         ret = regmap_write(bat->regmap,
 275                            bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_NORMAL);
 276         if (ret)
 277                 goto error;
 278
 279         return 0;
 280
 281 error:
 282         dev_err(bat->dev, "Failed to return normal mode: %pe\n", ERR_PTR(ret));
 283         return ret;
 284 }
 285
 286 static const struct of_device_id pm8916_bms_vm_battery_of_match[] = {
 287         { .compatible = "qcom,pm8916-bms-vm", },
 288         {}
 289 };
 290 MODULE_DEVICE_TABLE(of, pm8916_bms_vm_battery_of_match);
 291
 292 static struct platform_driver pm8916_bms_vm_battery_driver = {
 293         .driver = {
 294                 .name = "pm8916-bms-vm",
 295                 .of_match_table = pm8916_bms_vm_battery_of_match,
 296         },
 297         .probe = pm8916_bms_vm_battery_probe,
 298         .suspend = pm8916_bms_vm_battery_suspend,
 299         .resume = pm8916_bms_vm_battery_resume,
 300 };
 301 module_platform_driver(pm8916_bms_vm_battery_driver);
 302
 303 MODULE_DESCRIPTION("pm8916 BMS-VM driver");
 304 MODULE_AUTHOR("Nikita Travkin <nikita@trvn.ru>");
 305 MODULE_LICENSE("GPL");