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Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation

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  Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-20 17:30 +0100
    Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation Joe Perches <joe@perches.com> - 2016-12-20 19:00 +0100
      Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-12-21 16:40 +0100

#1545249 — Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation

Hi.

I have not got any comment, but does this seem
a right thing to do?

2016-10-19 13:38 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>:
> This code is working, but it should not depend on how "bool" is
> typedef'ed, or the bit position of I2C_M_RD.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
>
>  drivers/i2c/busses/i2c-uniphier-f.c | 2 +-
>  drivers/i2c/busses/i2c-uniphier.c   | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
> index db9105e..b54448e 100644
> --- a/drivers/i2c/busses/i2c-uniphier-f.c
> +++ b/drivers/i2c/busses/i2c-uniphier-f.c
> @@ -309,7 +309,7 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
>                                          struct i2c_msg *msg, bool stop)
>  {
>         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
> -       bool is_read = msg->flags & I2C_M_RD;
> +       bool is_read = !!(msg->flags & I2C_M_RD);
>         unsigned long time_left;
>
>         dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",
> diff --git a/drivers/i2c/busses/i2c-uniphier.c b/drivers/i2c/busses/i2c-uniphier.c
> index 56e92af..cc80bb2 100644
> --- a/drivers/i2c/busses/i2c-uniphier.c
> +++ b/drivers/i2c/busses/i2c-uniphier.c
> @@ -177,7 +177,7 @@ static int uniphier_i2c_stop(struct i2c_adapter *adap)
>  static int uniphier_i2c_master_xfer_one(struct i2c_adapter *adap,
>                                         struct i2c_msg *msg, bool stop)
>  {
> -       bool is_read = msg->flags & I2C_M_RD;
> +       bool is_read = !!(msg->flags & I2C_M_RD);
>         bool recovery = false;
>         int ret;
>
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel



-- 
Best Regards
Masahiro Yamada

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#1545329

On Wed, 2016-12-21 at 01:20 +0900, Masahiro Yamada wrote:
> Hi.
> 
> I have not got any comment, but does this seem
> a right thing to do?

> This code is working, but it should not depend on how "bool" is
> typedef'ed, or the bit position of I2C_M_RD.

<shrug>

I think bool can be guaranteed to be _Bool.

So a change not necessary as the original code
has a c90 guarantee of the same result.

6.3.1.2 Boolean type
1
When any scalar value is converted to _Bool, the result is 0 if the value compares equal
to 0; otherwise, the result is 1.


> 2016-10-19 13:38 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>:
[]
> > diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
[]
> > @@ -309,7 +309,7 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
> >                                          struct i2c_msg *msg, bool stop)
> >  {
> >         struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
> > -       bool is_read = msg->flags & I2C_M_RD;
> > +       bool is_read = !!(msg->flags & I2C_M_RD);
> >         unsigned long time_left;
> > 
> >         dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",

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#1545840

Hi Joe,


2016-12-21 2:55 GMT+09:00 Joe Perches <joe@perches.com>:
> On Wed, 2016-12-21 at 01:20 +0900, Masahiro Yamada wrote:
>> Hi.
>>
>> I have not got any comment, but does this seem
>> a right thing to do?
>
>> This code is working, but it should not depend on how "bool" is
>> typedef'ed, or the bit position of I2C_M_RD.
>
> <shrug>
>
> I think bool can be guaranteed to be _Bool.
>
> So a change not necessary as the original code
> has a c90 guarantee of the same result.
>
> 6.3.1.2 Boolean type
> 1
> When any scalar value is converted to _Bool, the result is 0 if the value compares equal
> to 0; otherwise, the result is 1.
>

Thanks for your comments!

_Bool works very nicely.

I have seen some (not very nice) projects
that define like "typedef char bool;"

So, I was wondering if I should write code
that works regardless how bool is defined.
Just my two cents.

-- 
Best Regards
Masahiro Yamada

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