gpiolib: fix hogs with multiple lines

After moving GPIO hog handling into GPIOLIB core, we accidentally stopped
supporting devicetree hog definitions with multiple lines like so:

	hog {
		gpio-hog;
		gpios = <3 0>, <4 GPIO_ACTIVE_LOW>;
		output-high;
		line-name = "foo";
	};

Restore this functionality to fix reported regressions.

Fixes: d1d564ec4992 ("gpio: move hogs into GPIO core")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdX6RuZXAozrF5m625ZepJTVVr4pcyKczSk12MedWvoejw@mail.gmail.com/
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260330-gpio-hogs-multiple-v3-1-175c3839ad9f@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9130f2e001acdaea1a7cd47001f390a296953856..076b7cfe2a1c7d076e39b5aac7d6fa87909a2d54 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -938,12 +938,18 @@ int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
        struct fwnode_handle *gc_node = dev_fwnode(&gc->gpiodev->dev);
        struct fwnode_reference_args gpiospec;
        enum gpiod_flags dflags;
+       const char *name = NULL;
        struct gpio_desc *desc;
+       unsigned int num_hogs;
        unsigned long lflags;
-       const char *name;
        int ret, argc;
-       u32 gpios[3]; /* We support up to three-cell bindings. */
-       u32 cells;
+       /*
+        * For devicetree-based systems, this needs to be defined in bindings
+        * and there's no real default value. For other firmware descriptions
+        * it makes the most sense to use 2 cells for the GPIO offset and
+        * request flags.
+        */
+       u32 cells = 2;
 
        lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
        dflags = GPIOD_ASIS;
@@ -952,42 +958,22 @@ int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
        argc = fwnode_property_count_u32(fwnode, "gpios");
        if (argc < 0)
                return argc;
-       if (argc > 3)
-               return -EINVAL;
 
-       ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios, argc);
-       if (ret < 0)
+       ret = fwnode_property_read_u32(gc_node, "#gpio-cells", &cells);
+       if (ret && is_of_node(fwnode))
                return ret;
+       if (argc % cells)
+               return -EINVAL;
 
-       if (is_of_node(fwnode)) {
-               /*
-                * OF-nodes need some additional special handling for
-                * translating of devicetree flags.
-                */
-               ret = fwnode_property_read_u32(gc_node, "#gpio-cells", &cells);
-               if (ret)
-                       return ret;
-               if (!ret && argc != cells)
-                       return -EINVAL;
-
-               memset(&gpiospec, 0, sizeof(gpiospec));
-               gpiospec.fwnode = fwnode;
-               gpiospec.nargs = argc;
+       num_hogs = argc / cells;
 
-               for (int i = 0; i < argc; i++)
-                       gpiospec.args[i] = gpios[i];
+       u32 *gpios __free(kfree) = kzalloc_objs(*gpios, argc);
+       if (!gpios)
+               return -ENOMEM;
 
-               ret = of_gpiochip_get_lflags(gc, &gpiospec, &lflags);
-               if (ret)
-                       return ret;
-       } else {
-               /*
-                * GPIO_ACTIVE_LOW is currently the only lookup flag
-                * supported for non-OF firmware nodes.
-                */
-               if (gpios[1])
-                       lflags |= GPIO_ACTIVE_LOW;
-       }
+       ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios, argc);
+       if (ret < 0)
+               return ret;
 
        if (fwnode_property_present(fwnode, "input"))
                dflags |= GPIOD_IN;
@@ -1000,11 +986,41 @@ int gpiochip_add_hog(struct gpio_chip *gc, struct fwnode_handle *fwnode)
 
        fwnode_property_read_string(fwnode, "line-name", &name);
 
-       desc = gpiochip_get_desc(gc, gpios[0]);
-       if (IS_ERR(desc))
-               return PTR_ERR(desc);
+       for (unsigned int i = 0; i < num_hogs; i++) {
+               if (is_of_node(fwnode)) {
+                       /*
+                        * OF-nodes need some additional special handling for
+                        * translating of devicetree flags.
+                        */
+                       memset(&gpiospec, 0, sizeof(gpiospec));
+                       gpiospec.fwnode = fwnode;
+                       gpiospec.nargs = cells;
+
+                       for (unsigned int j = 0; j < cells; j++)
+                               gpiospec.args[j] = gpios[i * cells + j];
+
+                       ret = of_gpiochip_get_lflags(gc, &gpiospec, &lflags);
+                       if (ret)
+                               return ret;
+               } else {
+                       /*
+                        * GPIO_ACTIVE_LOW is currently the only lookup flag
+                        * supported for non-OF firmware nodes.
+                        */
+                       if (gpios[i * cells + 1])
+                               lflags |= GPIO_ACTIVE_LOW;
+               }
+
+               desc = gpiochip_get_desc(gc, gpios[i * cells]);
+               if (IS_ERR(desc))
+                       return PTR_ERR(desc);
 
-       return gpiod_hog(desc, name, lflags, dflags);
+               ret = gpiod_hog(desc, name, lflags, dflags);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
 }
 
 static int gpiochip_hog_lines(struct gpio_chip *gc)