On Thu, Feb 24, 2022 at 11:19 AM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> The battery on the 2nd hand Surface 3 which I recently bought appears to
> not have a serial no programmed in. This results in any I2C reads from
> the registers containing the serial no failing with an I2C NACK.
>
> This was causing mshw0011_bix() to fail causing the battery readings to
> not work at all.
>
> Ignore EREMOTEIO (I2C NACK) errors when retrieving the serial no and
> continue with an empty serial no to fix this.
>
> Fixes: b1f81b496b0d ("platform/x86: surface3_power: MSHW0011 rev-eng implementation")
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
LGTM, (and scratching this off my list):
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Cheers,
Benjamin
> ---
> drivers/platform/surface/surface3_power.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/surface/surface3_power.c b/drivers/platform/surface/surface3_power.c
> index abac3eec565e..b283bc9bb5fd 100644
> --- a/drivers/platform/surface/surface3_power.c
> +++ b/drivers/platform/surface/surface3_power.c
> @@ -232,14 +232,21 @@ static int mshw0011_bix(struct mshw0011_data *cdata, struct bix *bix)
> }
> bix->last_full_charg_capacity = ret;
>
> - /* get serial number */
> + /*
> + * get serial number, on some devices (with unofficial replacement
> + * battery?) reading any of the serial no range addresses gets nacked
> + * in this case just leave the serial no empty.
> + */
> ret = i2c_smbus_read_i2c_block_data(client, MSHW0011_BAT0_REG_SERIAL_NO,
> sizeof(buf), buf);
> - if (ret != sizeof(buf)) {
> + if (ret == -EREMOTEIO) {
> + /* no serial number available */
> + } else if (ret != sizeof(buf)) {
> dev_err(&client->dev, "Error reading serial no: %d\n", ret);
> return ret;
> + } else {
> + snprintf(bix->serial, ARRAY_SIZE(bix->serial), "%3pE%6pE", buf + 7, buf);
> }
> - snprintf(bix->serial, ARRAY_SIZE(bix->serial), "%3pE%6pE", buf + 7, buf);
>
> /* get cycle count */
> ret = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_CYCLE_CNT);
> --
> 2.35.1
>
