clk: Skip clk provider registration when np is NULL

commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
revealed that clk/bcm/clk-raspberrypi.c driver calls
devm_of_clk_add_hw_provider(), with a NULL dev->of_node, which resulted in a
NULL pointer dereference in of_clk_add_hw_provider() when calling
fwnode_dev_initialized().

Returning 0 is reducing the if conditions in driver code and is being
consistent with the CONFIG_OF=n inline stub that returns 0 when CONFIG_OF
is disabled. The downside is that drivers will maybe register clkdev lookups
when they don't need to and waste some memory.

Fixes: 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added")
Fixes: 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20210426065618.588144-1-tudor.ambarus@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index e2ec1b7452439cde9a4fcf54c1b3c2e2954cf33d..65508eb89ec9965395ceb98e1aeb5c2f324e4cf1 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4540,6 +4540,9 @@ int of_clk_add_provider(struct device_node *np,
        struct of_clk_provider *cp;
        int ret;
 
+       if (!np)
+               return 0;
+
        cp = kzalloc(sizeof(*cp), GFP_KERNEL);
        if (!cp)
                return -ENOMEM;
@@ -4579,6 +4582,9 @@ int of_clk_add_hw_provider(struct device_node *np,
        struct of_clk_provider *cp;
        int ret;
 
+       if (!np)
+               return 0;
+
        cp = kzalloc(sizeof(*cp), GFP_KERNEL);
        if (!cp)
                return -ENOMEM;
@@ -4676,6 +4682,9 @@ void of_clk_del_provider(struct device_node *np)
 {
        struct of_clk_provider *cp;
 
+       if (!np)
+               return;
+
        mutex_lock(&of_clk_mutex);
        list_for_each_entry(cp, &of_clk_providers, link) {
                if (cp->node == np) {