On Thu, Apr 21, 2016 at 7:06 PM, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
> On Thu, Apr 21, 2016 at 01:08:21PM +0200, Linus Walleij wrote:
>> /**
>> + * of_gpiochip_set_names() - set up the names of the lines
>> + * @chip: GPIO chip whose lines should be named, if possible
>> + */
>> +static void of_gpiochip_set_names(struct gpio_chip *gc)
>> +{
>> + struct gpio_device *gdev = gc->gpiodev;
>> + struct device_node *np = gc->of_node;
>> + int i;
>> + int nstrings;
>> +
>> + /* Do we even have the "gpio-line-names" property */
>> + if (!of_property_read_bool(np, "gpio-line-names"))
>> + return;
>> +
>> + nstrings = of_property_count_strings(np, "gpio-line-names");
>> + /*
>> + * Make sure to not index beyond either the end of the
>> + * "gpio-names" array nor the number of descriptors of
>> + * the GPIO device.
>> + */
>
> I know you mentioned that it already been discussed much, but I am not
> sure why we need to count the string (and validate that strings are
> present by treating the property as boolean?),
I validate the property to be present to bail out quickly on controllers
that have no names set (i.e. all currently deployed device trees).
I can skip that part if you think it's too much optimization.
However:
> I am not
> sure why we need to count the string
> when we could do
> something like this (relying on the fact that
> of_property_read_string_index() returns 0 or negative error, no positive
> return codes):
>
> for (i = 0; i < gdev->ngpio; i++) {
> const char *name;
> int error;
>
> error = of_property_read_string_index(np,
> "gpio-line-names",
> i,
> &name);
> if (error) {
> if (error != -ENODATA)
> dev_err(&gdev->dev,
> "unable to name line %d: %d\n",
> i, error);
> /*
> * Either no more strings (-ENODATA), or
> * other error, in any case we are done naming.
> */
> break;
> }
>
> gdev->descs[i].name = name;
> }
Yeah I can do that, thanks I didn't look close enough at the semantics.
The big question whether the DT people are OK with naming producer
names like this remains however.
Yours,
Linus Walleij
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