linux-kernel - Re: [PATCH AUTOSEL 4.19 482/671] iio: tsl2772: Use devm_add_action_or_reset for tsl2772_chip

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Date:   Thu, 16 Jan 2020 18:16:18 +0000
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Sasha Levin <sashal@...nel.org>
CC:     <linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>,
        Chuhong Yuan <hslester96@...il.com>,
        Brian Masney <masneyb@...tation.org>,
        <linux-iio@...r.kernel.org>
Subject: Re: [PATCH AUTOSEL 4.19 482/671] iio: tsl2772: Use
 devm_add_action_or_reset for tsl2772_chip_off

On Thu, 16 Jan 2020 12:02:00 -0500
Sasha Levin <sashal@...nel.org> wrote:

> From: Chuhong Yuan <hslester96@...il.com>
> 
> [ Upstream commit 338084135aeddb103624a6841972fb8588295cc6 ]
> 
> Use devm_add_action_or_reset to call tsl2772_chip_off
> when the device is removed.
> This also fixes the issue that the chip is turned off
> before the device is unregistered.
> 
> Not marked for stable as fairly hard to hit the bug and
> this is in the middle of a set making other cleanups
> to the driver.  Hence will probably need explicit backporting.

Guess I was wrong and it does go on cleanly.  I took a quick
look at current 4.19 driver and looks like it's fine on it's
own.

We need to be careful with this one in general though.

Acked-by: Jonathan Cameron <Jonathan.Cameron@...wei.com> for 4.19

> 
> Signed-off-by: Chuhong Yuan <hslester96@...il.com>
> Fixes: c06c4d793584 ("staging: iio: tsl2x7x/tsl2772: move out of staging")
> Reviewed-by: Brian Masney <masneyb@...tation.org>
> Tested-by: Brian Masney <masneyb@...tation.org>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
>  drivers/iio/light/tsl2772.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/tsl2772.c b/drivers/iio/light/tsl2772.c
> index df5b2a0da96c..f2e308c6d6d7 100644
> --- a/drivers/iio/light/tsl2772.c
> +++ b/drivers/iio/light/tsl2772.c
> @@ -716,6 +716,13 @@ static int tsl2772_chip_off(struct iio_dev *indio_dev)
>  	return tsl2772_write_control_reg(chip, 0x00);
>  }
>  
> +static void tsl2772_chip_off_action(void *data)
> +{
> +	struct iio_dev *indio_dev = data;
> +
> +	tsl2772_chip_off(indio_dev);
> +}
> +
>  /**
>   * tsl2772_invoke_change - power cycle the device to implement the user
>   *                         parameters
> @@ -1711,9 +1718,14 @@ static int tsl2772_probe(struct i2c_client *clientp,
>  	if (ret < 0)
>  		return ret;
>  
> +	ret = devm_add_action_or_reset(&clientp->dev,
> +					tsl2772_chip_off_action,
> +					indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
>  	ret = iio_device_register(indio_dev);
>  	if (ret) {
> -		tsl2772_chip_off(indio_dev);
>  		dev_err(&clientp->dev,
>  			"%s: iio registration failed\n", __func__);
>  		return ret;
> @@ -1740,8 +1752,6 @@ static int tsl2772_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
> -	tsl2772_chip_off(indio_dev);
> -
>  	iio_device_unregister(indio_dev);
>  
>  	return 0;