On Thu, Aug 08, 2019 at 03:25:43PM +0200, Stefan Roese wrote:
> This patch fixes a backward compatibility issue, when boards use the
> old style GPIO suffix "-gpio" instead of the new "-gpios". This
> potential problem has been introduced by commit d99482673f95 ("serial:
> mctrl_gpio: Check if GPIO property exisits before requesting it").
>
> This patch now fixes this issue by iterating over all supported GPIO
> suffixes by using the newly introduced for_each_gpio_suffix() helper.
>
> Also, the string buffer is now allocated on the stack to avoid the
> problem of allocation in a loop and its potential failure.
> for (i = 0; i < UART_GPIO_MAX; i++) {
> enum gpiod_flags flags;
> - char *gpio_str;
> + const char *suffix;
> + char gpio_str[32]; /* 32 is max size of property name */
Hmm... don't we have some define for the maximum length of property?
Or maybe we can still continue using kasprintf() approach?
> bool present;
> + int k;
> +
> + /*
> + * Check if GPIO property exists and continue if not. Iterate
> + * over all supported GPIO suffixes (foo-gpios vs. foo-gpio).
> + */
> + for_each_gpio_suffix(k, suffix) {
> + snprintf(gpio_str, sizeof(gpio_str), "%s-%s",
> + mctrl_gpios_desc[i].name, suffix);
> +
> + present = device_property_present(dev, gpio_str);
> + if (present)
> + break;
> + }
>
> - /* Check if GPIO property exists and continue if not */
> - gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
> - mctrl_gpios_desc[i].name);
> - if (!gpio_str)
> - continue;
> -
> - present = device_property_present(dev, gpio_str);
Because there is no more explicit assignment of present outside of the loop,
the compiler may warn about uninitialized variable in use...
> - kfree(gpio_str);
> if (!present)
...here.
> continue;
--
With Best Regards,
Andy Shevchenko
