Re: [PATCH v2] gpio: gpiolib: clear the array_info's memory space

[Yan Wang]

Polite ping

On 5/4/2023 10:15 PM, Yan Wang wrote:
> > On May 4, 2023, at 19:36, Andy Shevchenko <andy.shevchenko@xxxxxxxxx> wrote:
> >
> > On Thu, May 4, 2023 at 12:38 PM Yan Wang <rk.code@xxxxxxxxxxx> wrote:
> > > On 4/26/2023 10:42 PM, andy.shevchenko@xxxxxxxxx wrote:
> > > > Sun, Apr 23, 2023 at 09:59:43PM +0800, Yan Wang kirjoitti:
> > > > > if hardware number different to array index,it needs to clear to points
> > > > > memory space if the array_info have been assigned a value.
> > > > Can you explain a bit more what's going on there?
> > ...
> >
> > > I use gpiod_get_array() to get a gpio array form the node of DTS.
> > >
> > > the node is as follows:
> > > ...
> > > gpios = <&gpio1 0 0>, <&gpio1 10 0>;
> > > ...
> > >
> > > First scan pin-0 of gpio1,its index and hardware number are 0,
> > >
> > > if (descs->ndescs == 0 && gpio_chip_hwgpio(desc) == 0) {
> > > ...
> > > descs->info = array_info.
> > > }
> > >
> > > Then scan pin-10 , its index is 1 ,but hardware number is 10 .
> > >
> > > if (gpio_chip_hwgpio(desc) != descs->ndescs) {
> > > array_info = NULL;
> > > }
> > > just set array_info = NULL, Should the array_info point to memory be
> > > cleared ?
> > This is a good question. The entire algorithm is a bit difficult to
> > understand from the first glance. I need some time to check it myself.
> Looking forward to your test results.
> > > if not cleared ,I use the gpiod_set_array_value_cansleep() to pull up or
> > > down pin-10 is invalid.
> > I'm not sure I follow. The array operations are against the given
> > array of the descriptors. If you ask to have that operation done, the
> > all descriptors in the array should be considered.
> >
> > > I found that the set_mask and get_mask vlaues of descs->info are seted
> > > 0x03 in gpiod_get_array(),
> > Yes, this mask is for the argument. The 0x03 is the correct one.
> >
> > > I think 0x401 is their correct value.
> > No. You have an array of two elements, and not 11.
> Due to hardware number are 10 and 0 , so this mask is 0x401（bit10 and bit0 are 1）.
>
> > > > > if (bitmap_full(array_info->get_mask, descs->ndescs)) {
> > > > > + /*clear descs->info*/
> > > > > + memset(array_info, 0, sizeof(struct gpio_array));
> > > > > array_info = NULL;
> > > > > }
> >
> > --
> > With Best Regards,
> > Andy Shevchenko