On 22/06/2022 06:28, Liang He wrote:
> of_find_node_by_name() will decrease the refcount of its first arg and
> we need to add a of_node_put() to keep refcount balance.
We do NOT need to add an of_node_put?
Anyway why do you add of_node_get which is not explained here?
>
> Besides, during the 'for' loop execution, the refcount of 'np' will be
> automatically increased and decreased. There is no need to call
> of_node_put() again.
>
> Signed-off-by: Liang He <windhl@xxxxxxx>
> ---
> drivers/memory/tegra/tegra20-emc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
> index 25ba3c5e4ad6..e43a5f8e188e 100644
> --- a/drivers/memory/tegra/tegra20-emc.c
> +++ b/drivers/memory/tegra/tegra20-emc.c
> @@ -477,6 +477,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
>
> ram_code = tegra_read_ram_code();
>
> + of_get_node(dev->of_node);
> for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
> np = of_find_node_by_name(np, "emc-tables")) {
> err = of_property_read_u32(np, "nvidia,ram-code", &value);
> @@ -484,6 +485,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
> struct device_node *lpddr2_np;
> bool cfg_mismatches = false;
>
> + of_node_get(np);
> lpddr2_np = of_find_node_by_name(np, "lpddr2");
> if (lpddr2_np) {
> const struct lpddr2_info *info;
> @@ -521,7 +523,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
> }
>
> if (cfg_mismatches) {
> - of_node_put(np);
> continue;
> }
> }
Best regards,
Krzysztof
