On Mon, Feb 23, 2015 at 05:51:22PM +0100, Lukasz Majewski wrote: > Hi Guenter, > > > On Mon, Feb 23, 2015 at 05:13:36PM +0100, Lukasz Majewski wrote: > > > Hi Guenter, > > > > > [ ... ] > > > > > > > > > > If devicetree is not configured, of_property_count_elems_of_size > > > > returns -ENOSYS, which is returned, causing the driver to fail > > > > loading. > > > > > > Has of_property_count_elems_of_size() returns -ENOSYS? > > > > > > Maybe something has changed, but in my linux-vanila (3.19-rc4) > > > at ./drivers/of/base.c it returns -EINVAL, -ENODATA or number of > > > elements. > > > > > > Have I missed something? > > > > > Hi Lukasz, > > > > Yes, you have. Check include/linux/of.h, line 484, in latest mainline. > > Ok. Now I got it. > > The above situation shouldn't happen if I put of_find_property() check > on the very beginning of this function (it returns NULL when DT support > is not compiled). > Correct. > The function would look as follows: > > int > pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx > *ctx) > { > struct device_node *np = dev->of_node; > int num, i, ret; > > if (!of_find_property(np, "cooling-levels", NULL)) > return 0; > > ret = of_property_count_u32_elems(np, "cooling-levels"); > if (ret <= 0) { > dev_err(dev, "Wrong data!\n"); > return ret; This should probably be something like return ret ? : -EINVAL; or ret == 0 is not an error, and you should not display an error message in that case. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html