linux-kernel - Re: [PATCH] Input: edt-ft5x06 - fix access to non-existing register

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Date:   Thu, 7 Sep 2017 14:34:17 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Luca Ceresoli <luca@...aceresoli.net>
Cc:     linux-input@...r.kernel.org,
        Lothar Waßmann <LW@...O-electronics.de>,
        Manfred Schlaegl <manfred.schlaegl@...zinger.com>,
        Rob Herring <robh@...nel.org>,
        Aniroop Mathur <a.mathur@...sung.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Martin Kepplinger <martink@...teo.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: edt-ft5x06 - fix access to non-existing register

On Tue, Sep 05, 2017 at 02:45:23PM +0200, Luca Ceresoli wrote:
> reg_addr->reg_report_rate is supposed to exist in M06, not M09.
> 
> The driver is written to skip avoids access to non-existing registers
> when the register address is NO_REGISTER (0xff). But
> reg_addr->reg_report_rate is initialized to 0x00 by devm_kzalloc() (in
> edt_ft5x06_ts_probe()) and not changed thereafter. So the checks do
> not work and an access to register 0x00 is done.
> 
> Fix by setting reg_addr->reg_report_rate to NO_REGISTER.
> 
> Also fix the only place where reg_report_rate is checked against zero
> instead of NO_REGISTER.
> 
> Signed-off-by: Luca Ceresoli <luca@...aceresoli.net>

Applied, thank you.

> ---
>  drivers/input/touchscreen/edt-ft5x06.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
> index f872817e81e4..5bf63f76ddda 100644
> --- a/drivers/input/touchscreen/edt-ft5x06.c
> +++ b/drivers/input/touchscreen/edt-ft5x06.c
> @@ -593,7 +593,7 @@ static int edt_ft5x06_work_mode(struct edt_ft5x06_ts_data *tsdata)
>  				  tsdata->gain);
>  	edt_ft5x06_register_write(tsdata, reg_addr->reg_offset,
>  				  tsdata->offset);
> -	if (reg_addr->reg_report_rate)
> +	if (reg_addr->reg_report_rate != NO_REGISTER)
>  		edt_ft5x06_register_write(tsdata, reg_addr->reg_report_rate,
>  				  tsdata->report_rate);
>  
> @@ -874,6 +874,7 @@ edt_ft5x06_ts_set_regs(struct edt_ft5x06_ts_data *tsdata)
>  
>  	case M09:
>  		reg_addr->reg_threshold = M09_REGISTER_THRESHOLD;
> +		reg_addr->reg_report_rate = NO_REGISTER;
>  		reg_addr->reg_gain = M09_REGISTER_GAIN;
>  		reg_addr->reg_offset = M09_REGISTER_OFFSET;
>  		reg_addr->reg_num_x = M09_REGISTER_NUM_X;
> -- 
> 2.7.4
> 

-- 
Dmitry