linux-kernel - Re: [PATCH 2/3] media: atomisp-gc2235: drop an unused var

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Date:   Mon, 15 Nov 2021 12:28:40 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc:     linuxarm@...wei.com, mauro.chehab@...wei.com,
        Beatriz Martins de Carvalho 
        <martinsdecarvalhobeatriz@...il.com>,
        Deepak R Varma <drv@...lo.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Tom Rix <trix@...hat.com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-staging@...ts.linux.dev, llvm@...ts.linux.dev
Subject: Re: [PATCH 2/3] media: atomisp-gc2235: drop an unused var

On Thu, Nov 11, 2021 at 11:08:52PM +0000, Mauro Carvalho Chehab wrote:
> Fix this clang Werror with W=1:
> 
> drivers/staging/media/atomisp/i2c/atomisp-gc2235.c:573:6: error: variable 'ret' set but not used [-Werror,-Wunused-but-set-variable]
>         int ret = -1;
>             ^
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> ---
> 

Looks good.

There should be warning for "int x = -1;" followed by |= because that's
a no-op OR assignment.

I'm surprised that clang doesn't print errors about the other
implementations of power_ctrl().

drivers/staging/media/atomisp/i2c/atomisp-mt9m114.c
   448  static int power_ctrl(struct v4l2_subdev *sd, bool flag)
   449  {
   450          int ret;
   451          struct mt9m114_device *dev = to_mt9m114_sensor(sd);
   452  
   453          if (!dev || !dev->platform_data)
   454                  return -ENODEV;
   455  
   456          if (flag) {
   457                  ret = dev->platform_data->v2p8_ctrl(sd, 1);
   458                  if (ret == 0) {
   459                          ret = dev->platform_data->v1p8_ctrl(sd, 1);
   460                          if (ret)
   461                                  ret = dev->platform_data->v2p8_ctrl(sd, 0);
   462                  }
   463          } else {
   464                  ret = dev->platform_data->v2p8_ctrl(sd, 0);
   465                  ret = dev->platform_data->v1p8_ctrl(sd, 0);
                        ^^^^^^

   466          }
   467          return ret;
   468  }
   469  
   470  static int gpio_ctrl(struct v4l2_subdev *sd, bool flag)
   471  {
   472          int ret;
   473          struct mt9m114_device *dev = to_mt9m114_sensor(sd);
   474  
   475          if (!dev || !dev->platform_data)
   476                  return -ENODEV;
   477  
   478          /*
   479           * Note: current modules wire only one GPIO signal (RESET#),
   480           * but the schematic wires up two to the connector.  BIOS
   481           * versions have been unfortunately inconsistent with which
   482           * ACPI index RESET# is on, so hit both
   483           */
   484  
   485          if (flag) {
   486                  ret = dev->platform_data->gpio0_ctrl(sd, 0);
   487                  ret = dev->platform_data->gpio1_ctrl(sd, 0);
                        ^^^^^^^

   488                  msleep(60);
   489                  ret |= dev->platform_data->gpio0_ctrl(sd, 1);
   490                  ret |= dev->platform_data->gpio1_ctrl(sd, 1);
   491          } else {

regards,
dan carpenter