[bug report] clk: mediatek: add missing cpu mux causing Mediatek cpufreq can't work

[bug report] clk: mediatek: add missing cpu mux causing Mediatek cpufreq can't work

[Dan Carpenter]

Hello Sean Wang,

The patch 1e17de9049da: "clk: mediatek: add missing cpu mux causing
Mediatek cpufreq can't work" from May 5, 2017, leads to the following
static checker warning:

	drivers/clk/mediatek/clk-cpumux.c:39 clk_cpumux_get_parent()
	warn: signedness bug returning '(-22)'

drivers/clk/mediatek/clk-cpumux.c
    27  static u8 clk_cpumux_get_parent(struct clk_hw *hw)
    28  {
    29          struct mtk_clk_cpumux *mux = to_mtk_clk_cpumux(hw);
    30          int num_parents = clk_hw_get_num_parents(hw);
    31          unsigned int val;
    32  
    33          regmap_read(mux->regmap, mux->reg, &val);
    34  
    35          val >>= mux->shift;
    36          val &= mux->mask;
    37  
    38          if (val >= num_parents)
    39                  return -EINVAL;
                        ^^^^^^^^^^^^^^
Doesn't work for u8.

    40  
    41          return val;
    42  }

regards,
dan carpenter

Re: [bug report] clk: mediatek: add missing cpu mux causing Mediatek cpufreq can't work

[Sean Wang]

Hi Dan, 

	thank you for reporting the defect, I will handle this int next days.
	Sean

On Fri, 2017-07-07 at 12:53 +0300, Dan Carpenter wrote:
> Hello Sean Wang,
> 
> The patch 1e17de9049da: "clk: mediatek: add missing cpu mux causing
> Mediatek cpufreq can't work" from May 5, 2017, leads to the following
> static checker warning:
> 
> 	drivers/clk/mediatek/clk-cpumux.c:39 clk_cpumux_get_parent()
> 	warn: signedness bug returning '(-22)'
> 
> drivers/clk/mediatek/clk-cpumux.c
>     27  static u8 clk_cpumux_get_parent(struct clk_hw *hw)
>     28  {
>     29          struct mtk_clk_cpumux *mux = to_mtk_clk_cpumux(hw);
>     30          int num_parents = clk_hw_get_num_parents(hw);
>     31          unsigned int val;
>     32  
>     33          regmap_read(mux->regmap, mux->reg, &val);
>     34  
>     35          val >>= mux->shift;
>     36          val &= mux->mask;
>     37  
>     38          if (val >= num_parents)
>     39                  return -EINVAL;
>                         ^^^^^^^^^^^^^^
> Doesn't work for u8.
> 
>     40  
>     41          return val;
>     42  }
> 
> regards,
> dan carpenter