drivers/power/supply/wilco-charger.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Charging control driver for the Wilco EC
   4  *
   5  * Copyright 2019 Google LLC
   6  *
   7  * See Documentation/ABI/testing/sysfs-class-power and
   8  * Documentation/ABI/testing/sysfs-class-power-wilco for userspace interface
   9  * and other info.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/platform_data/wilco-ec.h>
  15 #include <linux/power_supply.h>
  16
  17 #define DRV_NAME "wilco-charger"
  18
  19 /* Property IDs and related EC constants */
  20 #define PID_CHARGE_MODE         0x0710
  21 #define PID_CHARGE_LOWER_LIMIT  0x0711
  22 #define PID_CHARGE_UPPER_LIMIT  0x0712
  23
  24 enum charge_mode {
  25         CHARGE_MODE_STD = 1,    /* Used for Standard */
  26         CHARGE_MODE_EXP = 2,    /* Express Charge, used for Fast */
  27         CHARGE_MODE_AC = 3,     /* Mostly AC use, used for Trickle */
  28         CHARGE_MODE_AUTO = 4,   /* Used for Adaptive */
  29         CHARGE_MODE_CUSTOM = 5, /* Used for Custom */
  30         CHARGE_MODE_LONGLIFE = 6, /* Used for Long Life */
  31 };
  32
  33 #define CHARGE_LOWER_LIMIT_MIN  50
  34 #define CHARGE_LOWER_LIMIT_MAX  95
  35 #define CHARGE_UPPER_LIMIT_MIN  55
  36 #define CHARGE_UPPER_LIMIT_MAX  100
  37
  38 /* Convert from POWER_SUPPLY_PROP_CHARGE_TYPE value to the EC's charge mode */
  39 static int psp_val_to_charge_mode(int psp_val)
  40 {
  41         switch (psp_val) {
  42         case POWER_SUPPLY_CHARGE_TYPE_TRICKLE:
  43                 return CHARGE_MODE_AC;
  44         case POWER_SUPPLY_CHARGE_TYPE_FAST:
  45                 return CHARGE_MODE_EXP;
  46         case POWER_SUPPLY_CHARGE_TYPE_STANDARD:
  47                 return CHARGE_MODE_STD;
  48         case POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE:
  49                 return CHARGE_MODE_AUTO;
  50         case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
  51                 return CHARGE_MODE_CUSTOM;
  52         case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
  53                 return CHARGE_MODE_LONGLIFE;
  54         default:
  55                 return -EINVAL;
  56         }
  57 }
  58
  59 /* Convert from EC's charge mode to POWER_SUPPLY_PROP_CHARGE_TYPE value */
  60 static int charge_mode_to_psp_val(enum charge_mode mode)
  61 {
  62         switch (mode) {
  63         case CHARGE_MODE_AC:
  64                 return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
  65         case CHARGE_MODE_EXP:
  66                 return POWER_SUPPLY_CHARGE_TYPE_FAST;
  67         case CHARGE_MODE_STD:
  68                 return POWER_SUPPLY_CHARGE_TYPE_STANDARD;
  69         case CHARGE_MODE_AUTO:
  70                 return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
  71         case CHARGE_MODE_CUSTOM:
  72                 return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
  73         case CHARGE_MODE_LONGLIFE:
  74                 return POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
  75         default:
  76                 return -EINVAL;
  77         }
  78 }
  79
  80 static enum power_supply_property wilco_charge_props[] = {
  81         POWER_SUPPLY_PROP_CHARGE_TYPE,
  82         POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
  83         POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
  84 };
  85
  86 static int wilco_charge_get_property(struct power_supply *psy,
  87                                      enum power_supply_property psp,
  88                                      union power_supply_propval *val)
  89 {
  90         struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
  91         u32 property_id;
  92         int ret;
  93         u8 raw;
  94
  95         switch (psp) {
  96         case POWER_SUPPLY_PROP_CHARGE_TYPE:
  97                 property_id = PID_CHARGE_MODE;
  98                 break;
  99         case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
 100                 property_id = PID_CHARGE_LOWER_LIMIT;
 101                 break;
 102         case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
 103                 property_id = PID_CHARGE_UPPER_LIMIT;
 104                 break;
 105         default:
 106                 return -EINVAL;
 107         }
 108
 109         ret = wilco_ec_get_byte_property(ec, property_id, &raw);
 110         if (ret < 0)
 111                 return ret;
 112         if (property_id == PID_CHARGE_MODE) {
 113                 ret = charge_mode_to_psp_val(raw);
 114                 if (ret < 0)
 115                         return -EBADMSG;
 116                 raw = ret;
 117         }
 118         val->intval = raw;
 119
 120         return 0;
 121 }
 122
 123 static int wilco_charge_set_property(struct power_supply *psy,
 124                                      enum power_supply_property psp,
 125                                      const union power_supply_propval *val)
 126 {
 127         struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
 128         int mode;
 129
 130         switch (psp) {
 131         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 132                 mode = psp_val_to_charge_mode(val->intval);
 133                 if (mode < 0)
 134                         return -EINVAL;
 135                 return wilco_ec_set_byte_property(ec, PID_CHARGE_MODE, mode);
 136         case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
 137                 if (val->intval < CHARGE_LOWER_LIMIT_MIN ||
 138                     val->intval > CHARGE_LOWER_LIMIT_MAX)
 139                         return -EINVAL;
 140                 return wilco_ec_set_byte_property(ec, PID_CHARGE_LOWER_LIMIT,
 141                                                   val->intval);
 142         case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
 143                 if (val->intval < CHARGE_UPPER_LIMIT_MIN ||
 144                     val->intval > CHARGE_UPPER_LIMIT_MAX)
 145                         return -EINVAL;
 146                 return wilco_ec_set_byte_property(ec, PID_CHARGE_UPPER_LIMIT,
 147                                                   val->intval);
 148         default:
 149                 return -EINVAL;
 150         }
 151 }
 152
 153 static int wilco_charge_property_is_writeable(struct power_supply *psy,
 154                                               enum power_supply_property psp)
 155 {
 156         return 1;
 157 }
 158
 159 static const struct power_supply_desc wilco_ps_desc = {
 160         .properties             = wilco_charge_props,
 161         .num_properties         = ARRAY_SIZE(wilco_charge_props),
 162         .get_property           = wilco_charge_get_property,
 163         .set_property           = wilco_charge_set_property,
 164         .property_is_writeable  = wilco_charge_property_is_writeable,
 165         .name                   = DRV_NAME,
 166         .type                   = POWER_SUPPLY_TYPE_MAINS,
 167 };
 168
 169 static int wilco_charge_probe(struct platform_device *pdev)
 170 {
 171         struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 172         struct power_supply_config psy_cfg = {};
 173         struct power_supply *psy;
 174
 175         psy_cfg.drv_data = ec;
 176         psy = devm_power_supply_register(&pdev->dev, &wilco_ps_desc, &psy_cfg);
 177
 178         return PTR_ERR_OR_ZERO(psy);
 179 }
 180
 181 static struct platform_driver wilco_charge_driver = {
 182         .probe  = wilco_charge_probe,
 183         .driver = {
 184                 .name = DRV_NAME,
 185         }
 186 };
 187 module_platform_driver(wilco_charge_driver);
 188
 189 MODULE_ALIAS("platform:" DRV_NAME);
 190 MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
 191 MODULE_LICENSE("GPL v2");
 192 MODULE_DESCRIPTION("Wilco EC charge control driver");