[PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[marius.cristea]

From: Marius Cristea <marius.cristea@microchip.com>

The patch efea15e3c65d: "iio: adc: MCP3564: fix the static checker warning"
leads to the following Smatch static checker warning:

   smatch warnings:
   drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn: unsigned '__x' is never less than zero.

vim +/__x +1105 drivers/iio/adc/mcp3564.c

   1094
   1095  static void mcp3564_fill_scale_tbls(struct mcp3564_state *adc)
   1096  {
   .....
   1103          for (i = 0; i < MCP3564_MAX_PGA; i++) {
   1104                  ref = adc->vref_mv;
 > 1105                  tmp1 = shift_right((u64)ref * NANO, pow);
   1106                  div_u64_rem(tmp1, NANO, &tmp0);
   1107
   .....
   1113  }

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202309280738.NWjVfVt4-lkp@intel.com/
Fixes: efea15e3c65d (iio: adc: MCP3564: fix the static checker warning)
Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
 drivers/iio/adc/mcp3564.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
index 9ede1a5d5d7b..e3f1de5fcc5a 100644
--- a/drivers/iio/adc/mcp3564.c
+++ b/drivers/iio/adc/mcp3564.c
@@ -1102,7 +1102,7 @@ static void mcp3564_fill_scale_tbls(struct mcp3564_state *adc)
 
 	for (i = 0; i < MCP3564_MAX_PGA; i++) {
 		ref = adc->vref_mv;
-		tmp1 = shift_right((u64)ref * NANO, pow);
+		tmp1 = ((u64)ref * NANO) >> pow;
 		div_u64_rem(tmp1, NANO, &tmp0);
 
 		tmp1 = tmp1 * mcp3564_hwgain_frac[(2 * i) + 1];

base-commit: 5e99f692d4e32e3250ab18d511894ca797407aec
-- 
2.34.1

Re: [PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[Jonathan Cameron]

On Mon, 2 Oct 2023 19:16:18 +0300
<marius.cristea@microchip.com> wrote:

> From: Marius Cristea <marius.cristea@microchip.com>
> 
> The patch efea15e3c65d: "iio: adc: MCP3564: fix the static checker warning"
> leads to the following Smatch static checker warning:
> 
>    smatch warnings:
>    drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn: unsigned '__x' is never less than zero.
> 
> vim +/__x +1105 drivers/iio/adc/mcp3564.c
> 
>    1094
>    1095  static void mcp3564_fill_scale_tbls(struct mcp3564_state *adc)
>    1096  {
>    .....
>    1103          for (i = 0; i < MCP3564_MAX_PGA; i++) {
>    1104                  ref = adc->vref_mv;
>  > 1105                  tmp1 = shift_right((u64)ref * NANO, pow);  
>    1106                  div_u64_rem(tmp1, NANO, &tmp0);
>    1107
>    .....
>    1113  }
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202309280738.NWjVfVt4-lkp@intel.com/
> Fixes: efea15e3c65d (iio: adc: MCP3564: fix the static checker warning)

This fix is fine but can you talk me through how the static checker warning fix
in question has anything to do with this one?

Was it just a case of fixing that issue allowing the static checker to
get further before giving up?  In which case the description needs modifying.

Or am I missing something in the following fix?

diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
index 64145f4ae55c..9ede1a5d5d7b 100644
--- a/drivers/iio/adc/mcp3564.c
+++ b/drivers/iio/adc/mcp3564.c
@@ -1422,11 +1422,8 @@ static int mcp3564_probe(struct spi_device *spi)
        struct mcp3564_state *adc;
 
        indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
-       if (!indio_dev) {
-               dev_err_probe(&indio_dev->dev, PTR_ERR(indio_dev),
-                             "Can't allocate iio device\n");
+       if (!indio_dev)
                return -ENOMEM;
-       }
 
as that's all I'm seeing in that commit.

> Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> ---
>  drivers/iio/adc/mcp3564.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
> index 9ede1a5d5d7b..e3f1de5fcc5a 100644
> --- a/drivers/iio/adc/mcp3564.c
> +++ b/drivers/iio/adc/mcp3564.c
> @@ -1102,7 +1102,7 @@ static void mcp3564_fill_scale_tbls(struct mcp3564_state *adc)
>  
>  	for (i = 0; i < MCP3564_MAX_PGA; i++) {
>  		ref = adc->vref_mv;
> -		tmp1 = shift_right((u64)ref * NANO, pow);
> +		tmp1 = ((u64)ref * NANO) >> pow;
>  		div_u64_rem(tmp1, NANO, &tmp0);
>  
>  		tmp1 = tmp1 * mcp3564_hwgain_frac[(2 * i) + 1];
> 
> base-commit: 5e99f692d4e32e3250ab18d511894ca797407aec

Re: [PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[Marius.Cristea]

  Hi Jonathan,

 Sorry, I think I've made a "mistake" related to naming the patches and
also not running the Smatch checker at a point in time.



On Tue, 2023-10-10 at 10:44 +0100, Jonathan Cameron wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
> know the content is safe
> 
> On Mon, 2 Oct 2023 19:16:18 +0300
> <marius.cristea@microchip.com> wrote:
> 
> > From: Marius Cristea <marius.cristea@microchip.com>
> > 
> > The patch efea15e3c65d: "iio: adc: MCP3564: fix the static checker
> > warning"
> > leads to the following Smatch static checker warning:
> > 
> >    smatch warnings:
> >    drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
> > unsigned '__x' is never less than zero.
> > 
> > vim +/__x +1105 drivers/iio/adc/mcp3564.c
> > 
> >    1094
> >    1095  static void mcp3564_fill_scale_tbls(struct mcp3564_state
> > *adc)
> >    1096  {
> >    .....
> >    1103          for (i = 0; i < MCP3564_MAX_PGA; i++) {
> >    1104                  ref = adc->vref_mv;
> >  > 1105                  tmp1 = shift_right((u64)ref * NANO, pow);
> >    1106                  div_u64_rem(tmp1, NANO, &tmp0);
> >    1107
> >    .....
> >    1113  }
> > 
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes:
> > https://lore.kernel.org/oe-kbuild-all/202309280738.NWjVfVt4-lkp@intel.com/
> > Fixes: efea15e3c65d (iio: adc: MCP3564: fix the static checker
> > warning)
> 
> This fix is fine but can you talk me through how the static checker
> warning fix
> in question has anything to do with this one?
> 
> Was it just a case of fixing that issue allowing the static checker
> to
> get further before giving up?  In which case the description needs
> modifying.
> 
> Or am I missing something in the following fix?
> 
> diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
> index 64145f4ae55c..9ede1a5d5d7b 100644
> --- a/drivers/iio/adc/mcp3564.c
> +++ b/drivers/iio/adc/mcp3564.c
> @@ -1422,11 +1422,8 @@ static int mcp3564_probe(struct spi_device
> *spi)
>         struct mcp3564_state *adc;
> 
>         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
> -       if (!indio_dev) {
> -               dev_err_probe(&indio_dev->dev, PTR_ERR(indio_dev),
> -                             "Can't allocate iio device\n");
> +       if (!indio_dev)
>                 return -ENOMEM;
> -       }
> 
> 

  I've got two bugs reported:

- The first one was reported by Dan Carpenter "Re: [bug report] iio:
adc: adding support for MCP3564 ADC". This bug was found using the
"Smatch static checker warning" and it was related to:
> --> 1426                 dev_err_probe(&indio_dev->dev,
PTR_ERR(indio_dev),

This bug was fixed by the above "[PATCH v1] iio: adc: MCP3564: fix the
static checker warning" and it was applied on "Applied to the togreg
branch of iio.git as that's where this driver is at the moment."

Also my mistake at this point was that I didn't setup and run the
"Smatch static checker warning"


> as that's all I'm seeing in that commit.
> 
Yes, that commit only handled part of the fix.



> > Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> > ---
> >  drivers/iio/adc/mcp3564.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
> > index 9ede1a5d5d7b..e3f1de5fcc5a 100644
> > --- a/drivers/iio/adc/mcp3564.c
> > +++ b/drivers/iio/adc/mcp3564.c
> > @@ -1102,7 +1102,7 @@ static void mcp3564_fill_scale_tbls(struct
> > mcp3564_state *adc)
> > 
> >       for (i = 0; i < MCP3564_MAX_PGA; i++) {
> >               ref = adc->vref_mv;
> > -             tmp1 = shift_right((u64)ref * NANO, pow);
> > +             tmp1 = ((u64)ref * NANO) >> pow;
> >               div_u64_rem(tmp1, NANO, &tmp0);
> > 
> >               tmp1 = tmp1 * mcp3564_hwgain_frac[(2 * i) + 1];
> > 
> > base-commit: 5e99f692d4e32e3250ab18d511894ca797407aec
> 

- The second bug was reported by "kernel test robot <lkp@intel.com>"
also by running Smatch and it was run on the initial driver (without
having the first patch applied)

smatch warnings:
drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn: unsigned
'__x' is never less than zero.
drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing zero to
'PTR_ERR'
drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: address of NULL
pointer 'indio_dev'


The:"drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing zero
to 'PTR_ERR'" and "drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn:
address of NULL pointer 'indio_dev'" were fixed by the first patch.

The "drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
unsigned '__x' is never less than zero." is fixed by the last patch
"[PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less
than zero."
 by changeing:

-		tmp1 = shift_right((u64)ref * NANO, pow);
+		tmp1 = ((u64)ref * NANO) >> pow;

shift_right function is "Required to safely shift negative values" but
my value is always unsigned so it doesn't make sense to used it. This
error was reported when I have run the Smatch over the driver + first
patch (what was the latest from togreg).

I have applied the patch on top of what was the "latest" from togreg
branch and not on the initial driver.


I could change the description or I could provide a patch to handle
both warning reporting at once.

Thanks,
Marius

Re: [PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[Jonathan Cameron]

On Wed, 11 Oct 2023 16:41:38 +0000
<Marius.Cristea@microchip.com> wrote:

>   Hi Jonathan,
> 
>  Sorry, I think I've made a "mistake" related to naming the patches and
> also not running the Smatch checker at a point in time.
> 
> 
> 
> On Tue, 2023-10-10 at 10:44 +0100, Jonathan Cameron wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you
> > know the content is safe
> > 
> > On Mon, 2 Oct 2023 19:16:18 +0300
> > <marius.cristea@microchip.com> wrote:
> >   
> > > From: Marius Cristea <marius.cristea@microchip.com>
> > > 
> > > The patch efea15e3c65d: "iio: adc: MCP3564: fix the static checker
> > > warning"
> > > leads to the following Smatch static checker warning:
> > > 
> > >    smatch warnings:
> > >    drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
> > > unsigned '__x' is never less than zero.
> > > 
> > > vim +/__x +1105 drivers/iio/adc/mcp3564.c
> > > 
> > >    1094
> > >    1095  static void mcp3564_fill_scale_tbls(struct mcp3564_state
> > > *adc)
> > >    1096  {
> > >    .....
> > >    1103          for (i = 0; i < MCP3564_MAX_PGA; i++) {
> > >    1104                  ref = adc->vref_mv;  
> > >  > 1105                  tmp1 = shift_right((u64)ref * NANO, pow);  
> > >    1106                  div_u64_rem(tmp1, NANO, &tmp0);
> > >    1107
> > >    .....
> > >    1113  }
> > > 
> > > Reported-by: kernel test robot <lkp@intel.com>
> > > Closes:
> > > https://lore.kernel.org/oe-kbuild-all/202309280738.NWjVfVt4-lkp@intel.com/
> > > Fixes: efea15e3c65d (iio: adc: MCP3564: fix the static checker
> > > warning)  
> > 
> > This fix is fine but can you talk me through how the static checker
> > warning fix
> > in question has anything to do with this one?
> > 
> > Was it just a case of fixing that issue allowing the static checker
> > to
> > get further before giving up?  In which case the description needs
> > modifying.
> > 
> > Or am I missing something in the following fix?
> > 
> > diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
> > index 64145f4ae55c..9ede1a5d5d7b 100644
> > --- a/drivers/iio/adc/mcp3564.c
> > +++ b/drivers/iio/adc/mcp3564.c
> > @@ -1422,11 +1422,8 @@ static int mcp3564_probe(struct spi_device
> > *spi)
> >         struct mcp3564_state *adc;
> > 
> >         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
> > -       if (!indio_dev) {
> > -               dev_err_probe(&indio_dev->dev, PTR_ERR(indio_dev),
> > -                             "Can't allocate iio device\n");
> > +       if (!indio_dev)
> >                 return -ENOMEM;
> > -       }
> > 
> >   
> 
>   I've got two bugs reported:
> 
> - The first one was reported by Dan Carpenter "Re: [bug report] iio:
> adc: adding support for MCP3564 ADC". This bug was found using the
> "Smatch static checker warning" and it was related to:
> > --> 1426                 dev_err_probe(&indio_dev->dev,  
> PTR_ERR(indio_dev),
> 
> This bug was fixed by the above "[PATCH v1] iio: adc: MCP3564: fix the
> static checker warning" and it was applied on "Applied to the togreg
> branch of iio.git as that's where this driver is at the moment."
> 
> Also my mistake at this point was that I didn't setup and run the
> "Smatch static checker warning"
> 
> 
> > as that's all I'm seeing in that commit.
> >   
> Yes, that commit only handled part of the fix.
> 
> 
> 
> > > Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> > > ---
> > >  drivers/iio/adc/mcp3564.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/iio/adc/mcp3564.c b/drivers/iio/adc/mcp3564.c
> > > index 9ede1a5d5d7b..e3f1de5fcc5a 100644
> > > --- a/drivers/iio/adc/mcp3564.c
> > > +++ b/drivers/iio/adc/mcp3564.c
> > > @@ -1102,7 +1102,7 @@ static void mcp3564_fill_scale_tbls(struct
> > > mcp3564_state *adc)
> > > 
> > >       for (i = 0; i < MCP3564_MAX_PGA; i++) {
> > >               ref = adc->vref_mv;
> > > -             tmp1 = shift_right((u64)ref * NANO, pow);
> > > +             tmp1 = ((u64)ref * NANO) >> pow;
> > >               div_u64_rem(tmp1, NANO, &tmp0);
> > > 
> > >               tmp1 = tmp1 * mcp3564_hwgain_frac[(2 * i) + 1];
> > > 
> > > base-commit: 5e99f692d4e32e3250ab18d511894ca797407aec  
> >   
> 
> - The second bug was reported by "kernel test robot <lkp@intel.com>"
> also by running Smatch and it was run on the initial driver (without
> having the first patch applied)
> 
> smatch warnings:
> drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn: unsigned
> '__x' is never less than zero.
> drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing zero to
> 'PTR_ERR'
> drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: address of NULL
> pointer 'indio_dev'
> 
> 
> The:"drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing zero
> to 'PTR_ERR'" and "drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn:
> address of NULL pointer 'indio_dev'" were fixed by the first patch.
> 
> The "drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
> unsigned '__x' is never less than zero." is fixed by the last patch
> "[PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less
> than zero."
>  by changeing:
> 
> -		tmp1 = shift_right((u64)ref * NANO, pow);
> +		tmp1 = ((u64)ref * NANO) >> pow;
> 
> shift_right function is "Required to safely shift negative values" but
> my value is always unsigned so it doesn't make sense to used it. This
> error was reported when I have run the Smatch over the driver + first
> patch (what was the latest from togreg).
> 
> I have applied the patch on top of what was the "latest" from togreg
> branch and not on the initial driver.
> 
> 
> I could change the description or I could provide a patch to handle
> both warning reporting at once.
If there are multiple issues then should be multiple patches. So starting
point is definitely a version of this one with the correct description.

Thanks,

Jonathan

> 
> Thanks,
> Marius

Re: [PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never less than zero.

[Marius.Cristea]

Hi Jonathan,

On Thu, 2023-10-12 at 08:36 +0100, Jonathan Cameron wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
> know the content is safe
> 
> On Wed, 11 Oct 2023 16:41:38 +0000
> <Marius.Cristea@microchip.com> wrote:
> 
> >   Hi Jonathan,
> > 
> >  Sorry, I think I've made a "mistake" related to naming the patches
> > and
> > also not running the Smatch checker at a point in time.
> > 
> > 
> > 
> > On Tue, 2023-10-10 at 10:44 +0100, Jonathan Cameron wrote:
> > > EXTERNAL EMAIL: Do not click links or open attachments unless you
> > > know the content is safe
> > > 
> > > On Mon, 2 Oct 2023 19:16:18 +0300
> > > <marius.cristea@microchip.com> wrote:
> > > 
> > > > From: Marius Cristea <marius.cristea@microchip.com>
> > > > 
> > > > The patch efea15e3c65d: "iio: adc: MCP3564: fix the static
> > > > checker
> > > > warning"
> > > > leads to the following Smatch static checker warning:
> > > > 
> > > >    smatch warnings:
> > > >    drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls()
> > > > warn:
> > > > unsigned '__x' is never less than zero.
> > > > 
> > > > vim +/__x +1105 drivers/iio/adc/mcp3564.c
> > > > 
> > > >    1094
> > > >    1095  static void mcp3564_fill_scale_tbls(struct
> > > > mcp3564_state
> > > > *adc)
> > > >    1096  {
> > > >    .....
> > > >    1103          for (i = 0; i < MCP3564_MAX_PGA; i++) {
> > > >    1104                  ref = adc->vref_mv;
> > > >  > 1105                  tmp1 = shift_right((u64)ref * NANO,
> > > > pow);
> > > >    1106                  div_u64_rem(tmp1, NANO, &tmp0);
> > > >    1107
> > > >    .....
> > > >    1113  }
> > > > 
> > > > Reported-by: kernel test robot <lkp@intel.com>
> > > > Closes:
> > > > https://lore.kernel.org/oe-kbuild-all/202309280738.NWjVfVt4-lkp@intel.com/
> > > > Fixes: efea15e3c65d (iio: adc: MCP3564: fix the static checker
> > > > warning)
> > > 
> > > This fix is fine but can you talk me through how the static
> > > checker
> > > warning fix
> > > in question has anything to do with this one?
> > > 
> > > Was it just a case of fixing that issue allowing the static
> > > checker
> > > to
> > > get further before giving up?  In which case the description
> > > needs
> > > modifying.
> > > 
> > > Or am I missing something in the following fix?
> > > 
> > > diff --git a/drivers/iio/adc/mcp3564.c
> > > b/drivers/iio/adc/mcp3564.c
> > > index 64145f4ae55c..9ede1a5d5d7b 100644
> > > --- a/drivers/iio/adc/mcp3564.c
> > > +++ b/drivers/iio/adc/mcp3564.c
> > > @@ -1422,11 +1422,8 @@ static int mcp3564_probe(struct spi_device
> > > *spi)
> > >         struct mcp3564_state *adc;
> > > 
> > >         indio_dev = devm_iio_device_alloc(&spi->dev,
> > > sizeof(*adc));
> > > -       if (!indio_dev) {
> > > -               dev_err_probe(&indio_dev->dev,
> > > PTR_ERR(indio_dev),
> > > -                             "Can't allocate iio device\n");
> > > +       if (!indio_dev)
> > >                 return -ENOMEM;
> > > -       }
> > > 
> > > 
> > 
> >   I've got two bugs reported:
> > 
> > - The first one was reported by Dan Carpenter "Re: [bug report]
> > iio:
> > adc: adding support for MCP3564 ADC". This bug was found using the
> > "Smatch static checker warning" and it was related to:
> > > --> 1426                 dev_err_probe(&indio_dev->dev,
> > PTR_ERR(indio_dev),
> > 
> > This bug was fixed by the above "[PATCH v1] iio: adc: MCP3564: fix
> > the
> > static checker warning" and it was applied on "Applied to the
> > togreg
> > branch of iio.git as that's where this driver is at the moment."
> > 
> > Also my mistake at this point was that I didn't setup and run the
> > "Smatch static checker warning"
> > 
> > 
> > > as that's all I'm seeing in that commit.
> > > 
> > Yes, that commit only handled part of the fix.
> > 
> > 
> > 
> > > > Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
> > > > ---
> > > >  drivers/iio/adc/mcp3564.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/iio/adc/mcp3564.c
> > > > b/drivers/iio/adc/mcp3564.c
> > > > index 9ede1a5d5d7b..e3f1de5fcc5a 100644
> > > > --- a/drivers/iio/adc/mcp3564.c
> > > > +++ b/drivers/iio/adc/mcp3564.c
> > > > @@ -1102,7 +1102,7 @@ static void
> > > > mcp3564_fill_scale_tbls(struct
> > > > mcp3564_state *adc)
> > > > 
> > > >       for (i = 0; i < MCP3564_MAX_PGA; i++) {
> > > >               ref = adc->vref_mv;
> > > > -             tmp1 = shift_right((u64)ref * NANO, pow);
> > > > +             tmp1 = ((u64)ref * NANO) >> pow;
> > > >               div_u64_rem(tmp1, NANO, &tmp0);
> > > > 
> > > >               tmp1 = tmp1 * mcp3564_hwgain_frac[(2 * i) + 1];
> > > > 
> > > > base-commit: 5e99f692d4e32e3250ab18d511894ca797407aec
> > > 
> > 
> > - The second bug was reported by "kernel test robot
> > <lkp@intel.com>"
> > also by running Smatch and it was run on the initial driver
> > (without
> > having the first patch applied)
> > 
> > smatch warnings:
> > drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
> > unsigned
> > '__x' is never less than zero.
> > drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing zero
> > to
> > 'PTR_ERR'
> > drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: address of
> > NULL
> > pointer 'indio_dev'
> > 
> > 
> > The:"drivers/iio/adc/mcp3564.c:1426 mcp3564_probe() warn: passing
> > zero
> > to 'PTR_ERR'" and "drivers/iio/adc/mcp3564.c:1426 mcp3564_probe()
> > warn:
> > address of NULL pointer 'indio_dev'" were fixed by the first patch.
> > 
> > The "drivers/iio/adc/mcp3564.c:1105 mcp3564_fill_scale_tbls() warn:
> > unsigned '__x' is never less than zero." is fixed by the last patch
> > "[PATCH v1] iio: adc: MCP3564: fix warn: unsigned '__x' is never
> > less
> > than zero."
> >  by changeing:
> > 
> > -             tmp1 = shift_right((u64)ref * NANO, pow);
> > +             tmp1 = ((u64)ref * NANO) >> pow;
> > 
> > shift_right function is "Required to safely shift negative values"
> > but
> > my value is always unsigned so it doesn't make sense to used it.
> > This
> > error was reported when I have run the Smatch over the driver +
> > first
> > patch (what was the latest from togreg).
> > 
> > I have applied the patch on top of what was the "latest" from
> > togreg
> > branch and not on the initial driver.
> > 
> > 
> > I could change the description or I could provide a patch to handle
> > both warning reporting at once.
> If there are multiple issues then should be multiple patches. So
> starting
> point is definitely a version of this one with the correct
> description.
> 

Actually there was 2 bug reports and the second one includes the first
bug report.

For the first bug/warming report I already submit a patch that was
applied to togreg branch
(commit	efea15e3c65d96bac17a4d8104e3fff7c07cc910).

For the second bug/warming report I have "fixed" only the part that
wasn't fixed before.

I will resubmit this patch updating the description.



> Thanks,
> 
> Jonathan
> 
> > 
> > Thanks,
> > Marius
> 


Thanks,
Marius