Re: [RESEND 1/2] power: supply: add CW2015 Fuel Gauge driver

[Tobias Schramm]

Hi Sebastian,

thanks for the review!

> > +#ifdef CONFIG_OF
> > +static int cw2015_parse_dt(struct cw_battery *cw_bat)
> > +{
> > +	struct device *dev = &cw_bat->client->dev;
> > +	struct device_node *node = dev->of_node;
> > +	struct property *prop;
> > +	int length;
> > +	u32 value;
> > +	int ret;
> > +	struct cw_bat_platform_data *data = &cw_bat->plat_data;
> > +
> > +	if (!node)
> > +		return -ENODEV;
> > +
> > +	memset(data, 0, sizeof(*data));
> > +
> > +	/* determine the number of config info */
> > +	prop = of_find_property(node, PREFIX"bat-config-info", &length);
> > +	if (!prop)
> > +		return -EINVAL;
> > +
> > +	length /= sizeof(u32);
> > +
> > +	if (length > 0) {
> > +		size_t size = sizeof(*data->cw_bat_config_info) * length;
> > +
> > +		data->cw_bat_config_info = devm_kzalloc(dev, size, GFP_KERNEL);
> > +		if (!data->cw_bat_config_info)
> > +			return -ENOMEM;
> > +
> > +		ret = of_property_read_u32_array(node, PREFIX"bat-config-info",
> > +						 data->cw_bat_config_info,
> > +						 length);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
>
> In its current state it does not look like data for DT. What
> information is stored in this "config info"?
Truth is: I don't know. The format of this blob is neither disclosed nor 
even mentioned by publicly available datasheets.
As far as I can tell it is information about the battery used, most 
likely data on chemistry and design capacity of the pack.
Since this depends on the cell built into a device I'd expect it to be 
located in the DT.

> > +	cw_bat->bat_mode = MODE_BATTERY;
> > +	cw_bat->monitor_sec = CW2015_DEFAULT_MONITOR_SEC *
> > +			      CW2015_TIMER_MS_COUNTS;
> > +
> > +	prop = of_find_property(node, PREFIX"voltage-divider", &length);
> > +	if (prop) {
> > +		length /= sizeof(u32);
> > +		if (length != 2) {
> > +			dev_err(dev, "Length of voltage divider array must be "
> > +				"2, not %u\n", length);
> > +			return -EINVAL;
> > +		}
> > +		ret = of_property_read_u32_index(node, PREFIX"voltage-divider",
> > +						 0, &data->divider_high);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to read value of high side "
> > +				"voltage divider resistor: %d\n", ret);
> > +			return ret;
> > +		}
> > +		ret = of_property_read_u32_index(node, PREFIX"voltage-divider",
> > +						 1, &data->divider_low);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to read value of low side "
> > +				"voltage divider resistor: %d\n", ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	ret = of_property_read_u32(node, PREFIX"divider-res2", &value);
> > +	if (ret < 0)
> > +		value = 0;
> > +	data->divider_low = value;
> > +
> > +	ret = of_property_read_u32(node, PREFIX"virtual-power", &value);
> > +	if (ret < 0)
> > +		value = 0;
> > +	cw_bat->bat_mode = value;
>
> of_property_read_bool
>
> > +	ret = of_property_read_u32(node, PREFIX"monitor-interval", &value);
> > +	if (ret < 0)
> > +		dev_err(dev, "monitor-interval missing!\n");
> > +	else
> > +		cw_bat->monitor_sec = value * CW2015_TIMER_MS_COUNTS;
> > +
> > +	ret = of_property_read_u32(node, PREFIX"design-capacity", &value);
> > +	if (ret < 0) {
> > +		dev_err(dev, "design-capacity missing!\n");
> > +		data->design_capacity = 2000;
> > +	} else {
> > +		data->design_capacity = value;
> > +	}
> > +
> > +	of_property_read_u8(node, PREFIX"alert-level", &cw_bat->alert_level);
> > +	if (cw_bat->alert_level > 100) {
> > +		dev_err(dev, "invalid alert_level, clamping to 100 %%\n");
> > +		cw_bat->alert_level = 100;
> > +	}
>
> This does not belong into DT.
Is there any interface that allows setting a hardware battery alert 
level? Or should I just drop it altogether?

Tobias