Re: [PATCH v3 2/3] power: supply: bq27xxx: autodetect bq27411 and bq27541

[David Heidelberg <david@ixit.cz>]

On 10/09/2026 01:47, Rinat Muhamedgaliev wrote:
> Some replaceable battery packs used by OnePlus 6 and OnePlus 6T
> phones contain a bq27411, while others contain a bq27541. These
> devices require different register maps.
> 
> Add support for the generic ti,bq27xxx compatible. At probe time,
> issue the DeviceType control command and select the bq27411 or bq27541
> register map from the returned value.
> 
> Signed-off-by: Rinat Muhamedgaliev <rinat.muhamedgaliev@gmail.com>
> ---
>   drivers/power/supply/bq27xxx_battery_i2c.c | 39 ++++++++++++++++++++++
>   1 file changed, 39 insertions(+)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery_i2c.c b/drivers/power/supply/bq27xxx_battery_i2c.c
> index 868e95f..718f8e8 100644
> --- a/drivers/power/supply/bq27xxx_battery_i2c.c
> +++ b/drivers/power/supply/bq27xxx_battery_i2c.c
> @@ -16,6 +16,11 @@
>   
>   static DEFINE_IDA(battery_id);
>   
> +#define BQ27XXX_REG_CTRL		0x00
> +#define BQ27XXX_DEVICE_TYPE		0x0001
> +#define BQ27411_DEVICE_TYPE		0x0421
> +#define BQ27541_DEVICE_TYPE		0x0541
> +
>   static irqreturn_t bq27xxx_battery_irq_handler_thread(int irq, void *data)
>   {
>   	struct bq27xxx_device_info *di = data;
> @@ -153,6 +158,32 @@ static void bq27xxx_battery_i2c_devm_ida_free(void *data)
>   	ida_free(&battery_id, num);
>   }
>   
> +static int bq27xxx_battery_i2c_detect_chip(struct bq27xxx_device_info *di)
> +{
> +	int ret;
> +
> +	ret = di->bus.write(di, BQ27XXX_REG_CTRL, BQ27XXX_DEVICE_TYPE,
> +			    false);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = di->bus.read(di, BQ27XXX_REG_CTRL, false);
> +	if (ret < 0)
> +		return ret;
> +
> +	switch (ret) {
> +	case BQ27411_DEVICE_TYPE:
> +		di->chip = BQ27411;
> +		return 0;
> +	case BQ27541_DEVICE_TYPE:
> +		di->chip = BQ27541;
> +		return 0;
> +	default:
> +		dev_err(di->dev, "unsupported device type 0x%04x\n", ret);
> +		return -ENODEV;
> +	}
> +}
> +
>   static int bq27xxx_battery_i2c_probe(struct i2c_client *client)
>   {
>   	const struct i2c_device_id *id = i2c_client_get_device_id(client);
> @@ -188,6 +219,12 @@ static int bq27xxx_battery_i2c_probe(struct i2c_client *client)
>   	di->bus.read_bulk = bq27xxx_battery_i2c_bulk_read;
>   	di->bus.write_bulk = bq27xxx_battery_i2c_bulk_write;
>   
> +	if (!di->chip) {
> +		ret = bq27xxx_battery_i2c_detect_chip(di);
> +		if (ret)
> +			return ret;
> +	}
> +
>   	ret = bq27xxx_battery_setup(di);
>   	if (ret)
>   		return ret;
> @@ -225,6 +262,7 @@ static void bq27xxx_battery_i2c_remove(struct i2c_client *client)
>   }
>   
>   static const struct i2c_device_id bq27xxx_i2c_id_table[] = {
> +	{ "bq27xxx", 0 },
>   	{ "bq27200", BQ27000 },
>   	{ "bq27210", BQ27010 },
>   	{ "bq27500", BQ2750X },
> @@ -262,6 +300,7 @@ MODULE_DEVICE_TABLE(i2c, bq27xxx_i2c_id_table);
>   
>   #ifdef CONFIG_OF
>   static const struct of_device_id bq27xxx_battery_i2c_of_match_table[] = {
> +	{ .compatible = "ti,bq27xxx" },

Maybe some comment suggesting to use this compatible when autodetection is needed?

David

>   	{ .compatible = "ti,bq27200" },
>   	{ .compatible = "ti,bq27210" },
>   	{ .compatible = "ti,bq27500" },