On Mon, Mar 9, 2020 at 8:02 PM Doug Berger [off-list ref] wrote:

The default handling of the gpio-line-names property by the
gpiolib-of implementation does not work with the multiple
gpiochip banks per device structure used by the gpio-brcmstb
driver.

This commit adds driver level support for the device tree
property so that GPIO lines can be assigned friendly names.

Signed-off-by: Doug Berger <opendmb@gmail.com>
+static void brcmstb_gpio_set_names(struct device *dev,
+                                  struct brcmstb_gpio_bank *bank)
+{
+       struct device_node *np = dev->of_node;
+       const char **names;
+       int nstrings, base;

I don't understand why that thing is named "base".

+       unsigned int i;
+
+       base = bank->id * MAX_GPIO_PER_BANK;

That would be ngpios or something.

But you alread have what you need in bank->gc.ngpio, right?

So why calculate it?

+       nstrings = of_property_count_strings(np, "gpio-line-names");
+       if (nstrings <= base)
+               /* Line names not present */
+               return;
+
+       names = devm_kcalloc(dev, MAX_GPIO_PER_BANK, sizeof(*names),
+                            GFP_KERNEL);
+       if (!names)
+               return;
+
+       /*
+        * Make sure to not index beyond the end of the number of descriptors
+        * of the GPIO device.
+        */
+       for (i = 0; i < bank->width; i++) {
+               const char *name;
+               int ret;
+
+               ret = of_property_read_string_index(np, "gpio-line-names",
+                                                   base + i, &name);
+               if (ret) {
+                       if (ret != -ENODATA)
+                               dev_err(dev, "unable to name line %d: %d\n",
+                                       base + i, ret);
+                       break;
+               }
+               if (*name)
+                       names[i] = name;
+       }
+
+       bank->gc.names = names;
+}

Why can't you just make the function
devprop_gpiochip_set_names() public, (line in <linux/gpio/driver.h>)
and convert your np to a fwnode and call that &bank->gc ?

Yours,
Linus Walleij

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