linux-kernel - Re: [PATCH] platform/chrome: lightbar: Assign drvdata during probe

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Date:   Wed, 26 Jun 2019 22:34:08 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Rajat Jain <rajatja@...gle.com>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        linux-kernel@...r.kernel.org
Cc:     evgreen@...gle.com, rajatxjain@...il.com
Subject: Re: [PATCH] platform/chrome: lightbar: Assign drvdata during probe

Hi Rajat,

On 25/6/19 22:51, Rajat Jain wrote:
> The lightbar driver never assigned the drvdata in probe method, and thus
> causes a panic when it is accessed at the suspend time.

Good catch, that's one of the problems I currently have with mainline on Samus.
The other one, that I didn't find time to look at is, that for some reason, when
I suspend the system reboots. Is suspend/resume working for you in current mainline?

There is no drvdata because we don't really need extra private data for this
driver, the ec_dev is directly the drvdata provided by device parent. I am
wondering if you can just do

   struct cros_ec_dev *ec_dev = to_cros_ec_dev(dev);

in the suspend/resume calls like we do in the show/store calls or get the
drvdata from its parent. I guess I prefer the first one.

> 

Would be nice have a fixes tag here.

> Signed-off-by: Rajat Jain <rajatja@...gle.com>
> ---
>  drivers/platform/chrome/cros_ec_lightbar.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
> index d30a6650b0b5..98e514fc5830 100644
> --- a/drivers/platform/chrome/cros_ec_lightbar.c
> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
> @@ -578,11 +578,14 @@ static int cros_ec_lightbar_probe(struct platform_device *pd)
>  
>  	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
>  				 &cros_ec_lightbar_attr_group);
> -	if (ret < 0)
> +	if (ret < 0) {
>  		dev_err(dev, "failed to create %s attributes. err=%d\n",
>  			cros_ec_lightbar_attr_group.name, ret);
> +		return ret;
> +	}
>  
> -	return ret;
> +	platform_set_drvdata(pd, ec_dev);
> +	return 0;
>  }
>  
>  static int cros_ec_lightbar_remove(struct platform_device *pd)
> 

Thanks,
~ Enric