gpio: devres: Handle nonexclusive GPIOs

When we get a nonexeclusive GPIO descriptor using managed
resources, we should only add it to the list of managed
resources once: on the first user. Augment the
devm_gpiod_get_index() and devm_gpiod_get_from_of_node()
calls to account for this by checking if the descriptor
is already resource managed before we proceed to allocate
a new resource management struct.

Fixes: b0ce7b29bfcd ("regulator/gpio: Allow nonexclusive GPIO access")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
index 0195936..f9591b5 100644 (file)
--- a/drivers/gpio/gpiolib-devres.c
+++ b/drivers/gpio/gpiolib-devres.c
@@ -98,15 +98,28 @@ struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
        struct gpio_desc **dr;
        struct gpio_desc *desc;
 
+       desc = gpiod_get_index(dev, con_id, idx, flags);
+       if (IS_ERR(desc))
+               return desc;
+
+       /*
+        * For non-exclusive GPIO descriptors, check if this descriptor is
+        * already under resource management by this device.
+        */
+       if (flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
+               struct devres *dres;
+
+               dres = devres_find(dev, devm_gpiod_release,
+                                  devm_gpiod_match, &desc);
+               if (dres)
+                       return desc;
+       }
+
        dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
                          GFP_KERNEL);
-       if (!dr)
+       if (!dr) {
+               gpiod_put(desc);
                return ERR_PTR(-ENOMEM);
-
-       desc = gpiod_get_index(dev, con_id, idx, flags);
-       if (IS_ERR(desc)) {
-               devres_free(dr);
-               return desc;
        }
 
        *dr = desc;
@@ -140,15 +153,28 @@ struct gpio_desc *devm_gpiod_get_from_of_node(struct device *dev,
        struct gpio_desc **dr;
        struct gpio_desc *desc;
 
+       desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
+       if (IS_ERR(desc))
+               return desc;
+
+       /*
+        * For non-exclusive GPIO descriptors, check if this descriptor is
+        * already under resource management by this device.
+        */
+       if (dflags & GPIOD_FLAGS_BIT_NONEXCLUSIVE) {
+               struct devres *dres;
+
+               dres = devres_find(dev, devm_gpiod_release,
+                                  devm_gpiod_match, &desc);
+               if (dres)
+                       return desc;
+       }
+
        dr = devres_alloc(devm_gpiod_release, sizeof(struct gpio_desc *),
                          GFP_KERNEL);
-       if (!dr)
+       if (!dr) {
+               gpiod_put(desc);
                return ERR_PTR(-ENOMEM);
-
-       desc = gpiod_get_from_of_node(node, propname, index, dflags, label);
-       if (IS_ERR(desc)) {
-               devres_free(dr);
-               return desc;
        }
 
        *dr = desc;