linux-kernel - Re: [PATCH 2/2] Input: drv2667: Fix misuse of regmap_update

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Date:   Tue, 29 Nov 2016 17:39:40 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Florian Vaussard <florian.vaussard@...il.com>
Cc:     Dan Murphy <dmurphy@...com>, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Florian Vaussard <florian.vaussard@...g-vd.ch>
Subject: Re: [PATCH 2/2] Input: drv2667: Fix misuse of regmap_update_bits

On Tue, Nov 29, 2016 at 05:59:14PM +0100, Florian Vaussard wrote:
> Using regmap_update_bits(..., mask, 1) with 'mask' following (1 << k)
> and k greater than 0 is wrong. Indeed, _regmap_update_bits will perform
> (mask & 1), which results in 0 if LSB of mask is 0. Thus the call
> regmap_update_bits(..., mask, 1) is in reality equivalent to
> regmap_update_bits(..., mask, 0).
> 
> In such a case, the correct use is regmap_update_bits(..., mask, mask).
> 
> This driver is performing such a mistake with the DRV2667_STANDBY mask,
> which equals (1 << 6). Fix the driver to make it consistent with the
> API, and fix the alignment problem at the same time. Please note that
> this change is untested, as I do not have this piece of hardware.
> Testers are welcome!
> 
> Signed-off-by: Florian Vaussard <florian.vaussard@...g-vd.ch>

Applied, thank you.

> ---
>  drivers/input/misc/drv2667.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/misc/drv2667.c b/drivers/input/misc/drv2667.c
> index d5ba748..2849bb6 100644
> --- a/drivers/input/misc/drv2667.c
> +++ b/drivers/input/misc/drv2667.c
> @@ -256,7 +256,7 @@ static void drv2667_close(struct input_dev *input)
>  	cancel_work_sync(&haptics->work);
>  
>  	error = regmap_update_bits(haptics->regmap, DRV2667_CTRL_2,
> -				DRV2667_STANDBY, 1);
> +				   DRV2667_STANDBY, DRV2667_STANDBY);
>  	if (error)
>  		dev_err(&haptics->client->dev,
>  			"Failed to enter standby mode: %d\n", error);
> @@ -415,7 +415,7 @@ static int __maybe_unused drv2667_suspend(struct device *dev)
>  
>  	if (haptics->input_dev->users) {
>  		ret = regmap_update_bits(haptics->regmap, DRV2667_CTRL_2,
> -				DRV2667_STANDBY, 1);
> +					 DRV2667_STANDBY, DRV2667_STANDBY);
>  		if (ret) {
>  			dev_err(dev, "Failed to set standby mode\n");
>  			regulator_disable(haptics->regulator);
> -- 
> 2.5.5
> 

-- 
Dmitry