Hello Simon,

On wo, 2014-06-11 at 17:12 -0600, Simon Glass wrote:

Hi Jeroen,

On 11 June 2014 15:37, Jeroen Hofstee jeroen@myspectrum.nl wrote:

...

Hello Simon,

in commit 95a260a9

dm: Enable gpio command to support driver model

Now that named GPIO banks are supported, along with a way of obtaining the status of a GPIO (input or output), we can provide an enhanced GPIO command for driver model. Where the driver provides its own operation for obtaining the GPIO state, this is used, otherwise a generic version is sufficient.

you made the following change:

•   int gpio;
  

•   unsigned int gpio;
  
  

This breaks the code after it though:

    /* turn the gpio name into a gpio number */
    gpio = name_to_gpio(str_gpio);
    if (gpio < 0)
            goto show_usage;

And causes warnings with clang like:

common/cmd_gpio.c:159:11: warning: comparison of unsigned expression < 0 is always false [-Wtautological-compare] if (gpio < 0) ~~~~ ^ ~

Do you recall why it is made unsigned?

This is because gpio_lookup_name() needs an unsigned (-ve values have no meaning). I think that is what we want ultimately, but perhaps we need to go back to int in the meantime. The simplest fix would probably be to use a separate unsigned variable for the driver model code, and go back to an int for the current (old) code. The difference is that driver model returns a separate error code, whereas the old code combines the GPIO and error into a single value.

ok thanks. I will leave it alone then for now. Since the default lookup, simple_strtoul, is unsigned as well, it won't solve a common problem anyway.

Regards, Jeroen