On Tue, Dec 1, 2020 at 4:50 PM Johan Hovold <johan@xxxxxxxxxx> wrote:
> On Tue, Dec 01, 2020 at 03:37:38PM +0100, Linus Walleij wrote:
> > On Sun, Nov 22, 2020 at 6:08 PM Manivannan Sadhasivam <mani@xxxxxxxxxx> wrote:
> > You know the names of the pins...
> >
> > > + port_priv->gc.ngpio = 6;
> > > + port_priv->gc.label = "xr_gpios";
> > > + port_priv->gc.request = xr_gpio_request;
> > > + port_priv->gc.free = xr_gpio_free;
> > > + port_priv->gc.get_direction = xr_gpio_direction_get;
> > > + port_priv->gc.direction_input = xr_gpio_direction_input;
> > > + port_priv->gc.direction_output = xr_gpio_direction_output;
> > > + port_priv->gc.get = xr_gpio_get;
> > > + port_priv->gc.set = xr_gpio_set;
> > > + port_priv->gc.owner = THIS_MODULE;
> > > + port_priv->gc.parent = &port->dev;
> > > + port_priv->gc.base = -1;
> > > + port_priv->gc.can_sleep = true;
> >
> > So assign port_priv->gc.names here as well with an array
> > of strings with the names ("RI", "CD", ... etc).
> > This makes it look really nice in userspace if you do
> > e.g. "lsgpio".
>
> Last time we tried that gpiolib still used a flat namespace so that you
> can't have have more than one device using the same names. Unless that
> has changed this is a no-go. See
>
> https://lore.kernel.org/r/20180930122703.7115-1-johan@xxxxxxxxxx
>
> for our previous discussion about this.
Hm hm yeah we actually put in a nasty warning there since:
gpio = gpio_name_to_desc(gc->names[i]);
if (gpio)
dev_warn(&gdev->dev,
"Detected name collision for GPIO name '%s'\n",
gc->names[i]);
A better approach might be to create an array of names
prepended with something device-unique like the USB
bus topology? Or do we need a helper to help naming the
GPIOs? What would be helpful here?
name = kasprintf(GFP_KERNEL, "%s-NAME", topology_str);
Yours,
Linus Walleij
