On Mon, Mar 6, 2023 at 8:47 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote: ... > > > + ret = gpiochip_get_ngpios(gc, dev); > > > + if (ret) > > > + gc->ngpio = gc->bgpio_bits; > > > > But this doesn't update bgpio_bits in the success case. Can you explain why > > it's not a problem (should be at least in the code as a comment). > > In the success rate, the bgpio_bits would also be equal to "sz * 8" anyways. > The argument " unsigned long sz" passed in bgpio_init is specifically for this purpose. That tells the gpio library the gpio register access size. > if (!is_power_of_2(sz)) > return -EINVAL; > gc->bgpio_bits = sz * 8; > > If in the success case, we make it dependent on the ngpio value, we would need to round it up anyways to the closest (power of 2 && multiple of 8) which is the same as "sz * 8" > I will add a comment in the code in my next patch. I believe we should use only a single source for what we need. If we rely on ngpios, the bgpio_bits should be recalculated based on it. The expression doing this is very simple. Something like round_up(ngpios, 8); ... > > > + ret = device_property_read_u32(dev, "ngpios", &ngpios); > > > + if (ret) { > > > + chip_err(gc, "Failed to get ngpios property\n"); > > > + return -EINVAL; > > > + } > > > > This is not an equivalent to what was in the GPIO library. Why is it so? > > Sure. I will keep it the same in my next patch. No, you should take care about error codes properly. Now you are shadowing anything to -EINVAL. With this you must keep the comment in the code untouched (moved, but untouched). > The reason I didn’t is because I noticed that the final result of the logic is the same i.e. " goto err_free_dev_name" > "if(ret == -ENODATA)" is handled separately is to add an informative message: chip_err(gc, "tried to insert a GPIO chip with zero lines\n"); and return ret = -EINVAL. Yes, but you missed one out of three cases. > > > + gc->ngpio = ngpios; > > > + } ... > > > pr_err("%s: GPIOs %d..%d (%s) failed to register, %d\n", __func__, > > > - base, base + (int)ngpios - 1, > > > + base, base + (int)gc->ngpio - 1, > > > gc->label ? : "generic", ret); > > > > AFAIU this will give a different result to what was previous in one of the error > > cases. > > this one provides the "local" gpio pin id i.e. 0->31 for example. > chip_warn(gc, "line cnt %u is greater than fast path cnt %u\n", gc->ngpio, FASTPATH_NGPIO); > > while this one provides the "global" gpio pin id. when bgpio_init sets the base : gc->base = -1; and gpiochip_add_data_with_key applies this logic: > pr_err("%s: GPIOs %d..%d (%s) failed to register, %d\n", __func__, base, base + (int)gc->ngpio - 1, > base = gc->base; > if (base < 0) { > base = gpiochip_find_base(gc->ngpio); > Then the base would be = GPIO_DYNAMIC_BASE > > Apologies if I misunderstood your question? I'm talking about your change. It behaves differently in case of different errors and contents of gc->ngpio and the ngpios local variable. ... Please, check again carefully all possible branches and cases (there are few of them, not just a couple). -- With Best Regards, Andy Shevchenko