gpiolib: of: fix fallback quirks handling

We should only try to execute fallback quirks handling when previous
call returned -ENOENT, and not when we did not get -EPROBE_DEFER.
The other errors should be treated as hard errors: we did find the GPIO
description, but for some reason we failed to handle it properly.

The fallbacks should only be executed when previous handlers returned
-ENOENT, which means the mapping/description was not found.

Also let's remove the explicit deferral handling when iterating through
GPIO suffixes: it is not needed anymore as we will not be calling
fallbacks for anything but -ENOENT.

Fixes: df451f83 ("gpio: of: fix Freescale SPI CS quirk handling")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20190903231856.GA165165@dtor-wsReviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-of.c

@@ -343,36 +343,27 @@ struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
 
 		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
 						&of_flags);
-		/*
-		 * -EPROBE_DEFER in our case means that we found a
-		 * valid GPIO property, but no controller has been
-		 * registered so far.
-		 *
-		 * This means we don't need to look any further for
-		 * alternate name conventions, and we should really
-		 * preserve the return code for our user to be able to
-		 * retry probing later.
-		 */
-		if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER)
-			return desc;
 
-		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
+		if (!IS_ERR(desc) || PTR_ERR(desc) != -ENOENT)
 			break;
 	}
 
-	/* Special handling for SPI GPIOs if used */
-	if (IS_ERR(desc))
+	if (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT) {
+		/* Special handling for SPI GPIOs if used */
 		desc = of_find_spi_gpio(dev, con_id, &of_flags);
-	if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER) {
+	}
+
+	if (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT) {
 		/* This quirk looks up flags and all */
 		desc = of_find_spi_cs_gpio(dev, con_id, idx, flags);
 		if (!IS_ERR(desc))
 			return desc;
 	}
 
-	/* Special handling for regulator GPIOs if used */
-	if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER)
+	if (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT) {
+		/* Special handling for regulator GPIOs if used */
 		desc = of_find_regulator_gpio(dev, con_id, &of_flags);
+	}
 
 	if (IS_ERR(desc))
 		return desc;