Re: [PATCH] power: supply: sbs-battery: chromebook workaround for PEC

["Milan P. Stanić" <mps@arvanta.net>]

Hi,

On Mon, 2020-10-05 at 00:46, Sebastian Reichel wrote:
> Looks like the I2C tunnel implementation from Chromebook's
> embedded controller does not handle PEC correctly. Fix this
> by disabling PEC for batteries behind those I2C tunnels as
> a workaround.
> 
> Reported-by: "Milan P. Stanić" <mps@arvanta.net>
> Reported-by: Vicente Bergas <vicencb@gmail.com>
> CC: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Fixes: 7222bd603dd2 ("power: supply: sbs-battery: add PEC support")
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> ---
> Hi,
> 
> This is compile-tested only, since I do not have a chromebook at
> hand. Please test if this fixes your issue.
> 
> -- Sebastian
> ---
>  drivers/power/supply/sbs-battery.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
> index 13192cbcce71..b6a538ebb378 100644
> --- a/drivers/power/supply/sbs-battery.c
> +++ b/drivers/power/supply/sbs-battery.c
> @@ -279,6 +279,12 @@ static int sbs_update_presence(struct sbs_info *chip, bool is_present)
>  	else
>  		client->flags &= ~I2C_CLIENT_PEC;
>  
> +	if (of_device_is_compatible(client->dev.parent->of_node, "google,cros-ec-i2c-tunnel")
> +	    && client->flags & I2C_CLIENT_PEC) {
> +		dev_info(&client->dev, "Disabling PEC because of broken Cros-EC implementation\n");
> +		client->flags &= ~I2C_CLIENT_PEC;
> +	}
> +
>  	dev_dbg(&client->dev, "PEC: %s\n", (client->flags & I2C_CLIENT_PEC) ?
>  		"enabled" : "disabled");
  
Just for info, yesterday I built kernel 5.9-rc8 from:
https://gitlab.collabora.com/eballetbo/linux/-/commits/topic/chromeos/somewhat-stable-next
for Acer R13 chromebook (Mediatek mt8173, Machine model: Google Elm)
without above patch, and on it sbs-battery works without any problem.

Maybe problem is only on rk3399 (just guessing)

-- 
regards