diff options
Diffstat (limited to 'drivers/power/supply/ingenic-battery.c')
| -rw-r--r-- | drivers/power/supply/ingenic-battery.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/power/supply/ingenic-battery.c b/drivers/power/supply/ingenic-battery.c new file mode 100644 index 0000000000..2e7fdfde47 --- /dev/null +++ b/drivers/power/supply/ingenic-battery.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Battery driver for the Ingenic JZ47xx SoCs + * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu> + * + * based on drivers/power/supply/jz4740-battery.c + */ + +#include <linux/iio/consumer.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/power_supply.h> +#include <linux/property.h> + +struct ingenic_battery { + struct device *dev; + struct iio_channel *channel; + struct power_supply_desc desc; + struct power_supply *battery; + struct power_supply_battery_info *info; +}; + +static int ingenic_battery_get_property(struct power_supply *psy, + enum power_supply_property psp, + union power_supply_propval *val) +{ + struct ingenic_battery *bat = power_supply_get_drvdata(psy); + struct power_supply_battery_info *info = bat->info; + int ret; + + switch (psp) { + case POWER_SUPPLY_PROP_HEALTH: + ret = iio_read_channel_processed(bat->channel, &val->intval); + val->intval *= 1000; + if (val->intval < info->voltage_min_design_uv) + val->intval = POWER_SUPPLY_HEALTH_DEAD; + else if (val->intval > info->voltage_max_design_uv) + val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE; + else + val->intval = POWER_SUPPLY_HEALTH_GOOD; + return ret; + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + ret = iio_read_channel_processed(bat->channel, &val->intval); + val->intval *= 1000; + return ret; + case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN: + val->intval = info->voltage_min_design_uv; + return 0; + case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN: + val->intval = info->voltage_max_design_uv; + return 0; + default: + return -EINVAL; + } +} + +/* Set the most appropriate IIO channel voltage reference scale + * based on the battery's max voltage. + */ +static int ingenic_battery_set_scale(struct ingenic_battery *bat) +{ + const int *scale_raw; + int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret; + u64 max_mV; + + ret = iio_read_max_channel_raw(bat->channel, &max_raw); + if (ret) { + dev_err(bat->dev, "Unable to read max raw channel value\n"); + return ret; + } + + ret = iio_read_avail_channel_attribute(bat->channel, &scale_raw, + &scale_type, &scale_len, + IIO_CHAN_INFO_SCALE); + if (ret < 0) { + dev_err(bat->dev, "Unable to read channel avail scale\n"); + return ret; + } + if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2) + return -EINVAL; + + max_mV = bat->info->voltage_max_design_uv / 1000; + + for (i = 0; i < scale_len; i += 2) { + u64 scale_mV = (max_raw * scale_raw[i]) >> scale_raw[i + 1]; + + if (scale_mV < max_mV) + continue; + + if (best_idx >= 0 && scale_mV > best_mV) + continue; + + best_mV = scale_mV; + best_idx = i; + } + + if (best_idx < 0) { + dev_err(bat->dev, "Unable to find matching voltage scale\n"); + return -EINVAL; + } + + /* Only set scale if there is more than one (fractional) entry */ + if (scale_len > 2) { + ret = iio_write_channel_attribute(bat->channel, + scale_raw[best_idx], + scale_raw[best_idx + 1], + IIO_CHAN_INFO_SCALE); + if (ret) + return ret; + } + + return 0; +} + +static enum power_supply_property ingenic_battery_properties[] = { + POWER_SUPPLY_PROP_HEALTH, + POWER_SUPPLY_PROP_VOLTAGE_NOW, + POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, + POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, +}; + +static int ingenic_battery_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct ingenic_battery *bat; + struct power_supply_config psy_cfg = {}; + struct power_supply_desc *desc; + int ret; + + bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL); + if (!bat) + return -ENOMEM; + + bat->dev = dev; + bat->channel = devm_iio_channel_get(dev, "battery"); + if (IS_ERR(bat->channel)) + return PTR_ERR(bat->channel); + + desc = &bat->desc; + desc->name = "jz-battery"; + desc->type = POWER_SUPPLY_TYPE_BATTERY; + desc->properties = ingenic_battery_properties; + desc->num_properties = ARRAY_SIZE(ingenic_battery_properties); + desc->get_property = ingenic_battery_get_property; + psy_cfg.drv_data = bat; + psy_cfg.of_node = dev->of_node; + + bat->battery = devm_power_supply_register(dev, 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) { + dev_err(dev, "Unable to get battery info: %d\n", ret); + return ret; + } + if (bat->info->voltage_min_design_uv < 0) { + dev_err(dev, "Unable to get voltage min design\n"); + return bat->info->voltage_min_design_uv; + } + if (bat->info->voltage_max_design_uv < 0) { + dev_err(dev, "Unable to get voltage max design\n"); + return bat->info->voltage_max_design_uv; + } + + return ingenic_battery_set_scale(bat); +} + +#ifdef CONFIG_OF +static const struct of_device_id ingenic_battery_of_match[] = { + { .compatible = "ingenic,jz4740-battery", }, + { }, +}; +MODULE_DEVICE_TABLE(of, ingenic_battery_of_match); +#endif + +static struct platform_driver ingenic_battery_driver = { + .driver = { + .name = "ingenic-battery", + .of_match_table = of_match_ptr(ingenic_battery_of_match), + }, + .probe = ingenic_battery_probe, +}; +module_platform_driver(ingenic_battery_driver); + +MODULE_DESCRIPTION("Battery driver for Ingenic JZ47xx SoCs"); +MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>"); +MODULE_LICENSE("GPL"); |