Thanks,
Jonathan
> ---
>
> Changes:
>
> v2: - rework the return logic in ingenic_battery_get_property,
> - make index offsets point forward in
ingenic_battery_set_scale,
> - fix spacing around scale_raw[best_idx + 1]
>
> drivers/power/supply/Kconfig | 11 ++
> drivers/power/supply/Makefile | 1 +
> drivers/power/supply/ingenic-battery.c | 180
+++++++++++++++++++++++++
> 3 files changed, 192 insertions(+)
> create mode 100644 drivers/power/supply/ingenic-battery.c
>
> diff --git a/drivers/power/supply/Kconfig
b/drivers/power/supply/Kconfig
> index e901b9879e7e..9bfb1637ec28 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -169,6 +169,17 @@ config BATTERY_COLLIE
> Say Y to enable support for the battery on the Sharp Zaurus
> SL-5500 (collie) models.
>
> +config BATTERY_INGENIC
> + tristate "Ingenic JZ47xx SoCs battery driver"
> + depends on MIPS || COMPILE_TEST
> + depends on INGENIC_ADC
> + help
> + Choose this option if you want to monitor battery status on
> + Ingenic JZ47xx SoC based devices.
> +
> + This driver can also be built as a module. If so, the module
will be
> + called ingenic-battery.
> +
> config BATTERY_IPAQ_MICRO
> tristate "iPAQ Atmel Micro ASIC battery driver"
> depends on MFD_IPAQ_MICRO
> diff --git a/drivers/power/supply/Makefile
b/drivers/power/supply/Makefile
> index b731c2a9b695..9e2c481d0187 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -34,6 +34,7 @@ obj-$(CONFIG_BATTERY_PMU) += pmu_battery.o
> obj-$(CONFIG_BATTERY_OLPC) += olpc_battery.o
> obj-$(CONFIG_BATTERY_TOSA) += tosa_battery.o
> obj-$(CONFIG_BATTERY_COLLIE) += collie_battery.o
> +obj-$(CONFIG_BATTERY_INGENIC) += ingenic-battery.o
> obj-$(CONFIG_BATTERY_IPAQ_MICRO) += ipaq_micro_battery.o
> obj-$(CONFIG_BATTERY_WM97XX) += wm97xx_battery.o
> obj-$(CONFIG_BATTERY_SBS) += sbs-battery.o
> diff --git a/drivers/power/supply/ingenic-battery.c
b/drivers/power/supply/ingenic-battery.c
> new file mode 100644
> index 000000000000..822aee1c7b64
> --- /dev/null
> +++ b/drivers/power/supply/ingenic-battery.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Battery driver for the Ingenic JZ47xx SoCs
> + * Copyright (c) 2019 Artur Rojek <contact@xxxxxxxxxxxxxx>
> + *
> + * 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;
> + }
> +
> + return iio_write_channel_attribute(bat->channel,
> + scale_raw[best_idx],
> + scale_raw[best_idx + 1],
> + IIO_CHAN_INFO_SCALE);
> +}
> +
> +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)) {
> + dev_err(dev, "Unable to register battery\n");
> + return PTR_ERR(bat->battery);
> + }
> +
> + 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),
I guess we can be fairly sure no one will even user this with ACPI
(magic DT) bindings? That would make this a rare case where the
of_match_pr protection and ifdef fun is still fine.
> + },
> + .probe = ingenic_battery_probe,
> +};
> +module_platform_driver(ingenic_battery_driver);
