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1// SPDX-License-Identifier: GPL-2.02/*3 * Battery driver for the Ingenic JZ47xx SoCs4 * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>5 *6 * based on drivers/power/supply/jz4740-battery.c7 */8 9#include <linux/iio/consumer.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/power_supply.h>14#include <linux/property.h>15 16struct ingenic_battery {17 struct device *dev;18 struct iio_channel *channel;19 struct power_supply_desc desc;20 struct power_supply *battery;21 struct power_supply_battery_info *info;22};23 24static int ingenic_battery_get_property(struct power_supply *psy,25 enum power_supply_property psp,26 union power_supply_propval *val)27{28 struct ingenic_battery *bat = power_supply_get_drvdata(psy);29 struct power_supply_battery_info *info = bat->info;30 int ret;31 32 switch (psp) {33 case POWER_SUPPLY_PROP_HEALTH:34 ret = iio_read_channel_processed_scale(bat->channel,35 &val->intval,36 1000);37 if (val->intval < info->voltage_min_design_uv)38 val->intval = POWER_SUPPLY_HEALTH_DEAD;39 else if (val->intval > info->voltage_max_design_uv)40 val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;41 else42 val->intval = POWER_SUPPLY_HEALTH_GOOD;43 return ret;44 case POWER_SUPPLY_PROP_VOLTAGE_NOW:45 ret = iio_read_channel_processed_scale(bat->channel,46 &val->intval,47 1000);48 return ret;49 case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:50 val->intval = info->voltage_min_design_uv;51 return 0;52 case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:53 val->intval = info->voltage_max_design_uv;54 return 0;55 default:56 return -EINVAL;57 }58}59 60/* Set the most appropriate IIO channel voltage reference scale61 * based on the battery's max voltage.62 */63static int ingenic_battery_set_scale(struct ingenic_battery *bat)64{65 const int *scale_raw;66 int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret;67 u64 max_mV;68 69 ret = iio_read_max_channel_raw(bat->channel, &max_raw);70 if (ret) {71 dev_err(bat->dev, "Unable to read max raw channel value\n");72 return ret;73 }74 75 ret = iio_read_avail_channel_attribute(bat->channel, &scale_raw,76 &scale_type, &scale_len,77 IIO_CHAN_INFO_SCALE);78 if (ret < 0) {79 dev_err(bat->dev, "Unable to read channel avail scale\n");80 return ret;81 }82 if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2)83 return -EINVAL;84 85 max_mV = bat->info->voltage_max_design_uv / 1000;86 87 for (i = 0; i < scale_len; i += 2) {88 u64 scale_mV = (max_raw * scale_raw[i]) >> scale_raw[i + 1];89 90 if (scale_mV < max_mV)91 continue;92 93 if (best_idx >= 0 && scale_mV > best_mV)94 continue;95 96 best_mV = scale_mV;97 best_idx = i;98 }99 100 if (best_idx < 0) {101 dev_err(bat->dev, "Unable to find matching voltage scale\n");102 return -EINVAL;103 }104 105 /* Only set scale if there is more than one (fractional) entry */106 if (scale_len > 2) {107 ret = iio_write_channel_attribute(bat->channel,108 scale_raw[best_idx],109 scale_raw[best_idx + 1],110 IIO_CHAN_INFO_SCALE);111 if (ret)112 return ret;113 }114 115 return 0;116}117 118static enum power_supply_property ingenic_battery_properties[] = {119 POWER_SUPPLY_PROP_HEALTH,120 POWER_SUPPLY_PROP_VOLTAGE_NOW,121 POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,122 POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,123};124 125static int ingenic_battery_probe(struct platform_device *pdev)126{127 struct device *dev = &pdev->dev;128 struct ingenic_battery *bat;129 struct power_supply_config psy_cfg = {};130 struct power_supply_desc *desc;131 int ret;132 133 bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);134 if (!bat)135 return -ENOMEM;136 137 bat->dev = dev;138 bat->channel = devm_iio_channel_get(dev, "battery");139 if (IS_ERR(bat->channel))140 return PTR_ERR(bat->channel);141 142 desc = &bat->desc;143 desc->name = "jz-battery";144 desc->type = POWER_SUPPLY_TYPE_BATTERY;145 desc->properties = ingenic_battery_properties;146 desc->num_properties = ARRAY_SIZE(ingenic_battery_properties);147 desc->get_property = ingenic_battery_get_property;148 psy_cfg.drv_data = bat;149 psy_cfg.of_node = dev->of_node;150 151 bat->battery = devm_power_supply_register(dev, desc, &psy_cfg);152 if (IS_ERR(bat->battery))153 return dev_err_probe(dev, PTR_ERR(bat->battery),154 "Unable to register battery\n");155 156 ret = power_supply_get_battery_info(bat->battery, &bat->info);157 if (ret) {158 dev_err(dev, "Unable to get battery info: %d\n", ret);159 return ret;160 }161 if (bat->info->voltage_min_design_uv < 0) {162 dev_err(dev, "Unable to get voltage min design\n");163 return bat->info->voltage_min_design_uv;164 }165 if (bat->info->voltage_max_design_uv < 0) {166 dev_err(dev, "Unable to get voltage max design\n");167 return bat->info->voltage_max_design_uv;168 }169 170 return ingenic_battery_set_scale(bat);171}172 173#ifdef CONFIG_OF174static const struct of_device_id ingenic_battery_of_match[] = {175 { .compatible = "ingenic,jz4740-battery", },176 { },177};178MODULE_DEVICE_TABLE(of, ingenic_battery_of_match);179#endif180 181static struct platform_driver ingenic_battery_driver = {182 .driver = {183 .name = "ingenic-battery",184 .of_match_table = of_match_ptr(ingenic_battery_of_match),185 },186 .probe = ingenic_battery_probe,187};188module_platform_driver(ingenic_battery_driver);189 190MODULE_DESCRIPTION("Battery driver for Ingenic JZ47xx SoCs");191MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>");192MODULE_LICENSE("GPL");193