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

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Date:   Tue, 20 Dec 2016 09:55:38 -0800
From:   Joe Perches <joe@...ches.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-i2c@...r.kernel.org
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Wolfram Sang <wsa@...-dreams.de>
Subject: Re: [PATCH] i2c: uniphier[-f]: fix bool logic calculation

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@...ionext.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",