Input: tegra-kbc - use of_property_read_variable_u32_array() and of_property_present()

There's no need to get the length of an DT array property before
parsing the array. of_property_read_variable_u32_array() takes a
minimum and maximum length and returns the actual length (or error
code).

This is part of a larger effort to remove callers of of_get_property()
and similar functions. of_get_property() leaks the DT property data
pointer which is a problem for dynamically allocated nodes which may
be freed.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240913200827.546649-1-robh@kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
index 204ba18..6776dd9 100644 (file)
--- a/drivers/input/keyboard/tegra-kbc.c
+++ b/drivers/input/keyboard/tegra-kbc.c
@@ -484,12 +484,10 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
        struct device_node *np = kbc->dev->of_node;
        u32 prop;
        int i;
-       u32 num_rows = 0;
-       u32 num_cols = 0;
+       int num_rows;
+       int num_cols;
        u32 cols_cfg[KBC_MAX_GPIO];
        u32 rows_cfg[KBC_MAX_GPIO];
-       int proplen;
-       int ret;
 
        if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
                kbc->debounce_cnt = prop;
@@ -503,56 +501,23 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
            of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
                kbc->wakeup = true;
 
-       if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
-               dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
-               return -ENOENT;
-       }
-       num_rows = proplen / sizeof(u32);
-
-       if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
-               dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
-               return -ENOENT;
-       }
-       num_cols = proplen / sizeof(u32);
-
-       if (num_rows > kbc->hw_support->max_rows) {
-               dev_err(kbc->dev,
-                       "Number of rows is more than supported by hardware\n");
-               return -EINVAL;
-       }
-
-       if (num_cols > kbc->hw_support->max_columns) {
-               dev_err(kbc->dev,
-                       "Number of cols is more than supported by hardware\n");
-               return -EINVAL;
-       }
-
-       if (!of_get_property(np, "linux,keymap", &proplen)) {
+       if (!of_property_present(np, "linux,keymap")) {
                dev_err(kbc->dev, "property linux,keymap not found\n");
                return -ENOENT;
        }
 
-       if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
-               dev_err(kbc->dev,
-                       "keypad rows/columns not properly specified\n");
-               return -EINVAL;
-       }
-
        /* Set all pins as non-configured */
        for (i = 0; i < kbc->num_rows_and_columns; i++)
                kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
 
-       ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
-                               rows_cfg, num_rows);
-       if (ret < 0) {
+       num_rows = of_property_read_variable_u32_array(np, "nvidia,kbc-row-pins",
+                               rows_cfg, 1, KBC_MAX_GPIO);
+       if (num_rows < 0) {
                dev_err(kbc->dev, "Rows configurations are not proper\n");
-               return -EINVAL;
-       }
-
-       ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
-                               cols_cfg, num_cols);
-       if (ret < 0) {
-               dev_err(kbc->dev, "Cols configurations are not proper\n");
+               return num_rows;
+       } else if (num_rows > kbc->hw_support->max_rows) {
+               dev_err(kbc->dev,
+                       "Number of rows is more than supported by hardware\n");
                return -EINVAL;
        }
 
@@ -561,11 +526,28 @@ static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
                kbc->pin_cfg[rows_cfg[i]].num = i;
        }
 
+       num_cols = of_property_read_variable_u32_array(np, "nvidia,kbc-col-pins",
+                               cols_cfg, 1, KBC_MAX_GPIO);
+       if (num_cols < 0) {
+               dev_err(kbc->dev, "Cols configurations are not proper\n");
+               return num_cols;
+       } else if (num_cols > kbc->hw_support->max_columns) {
+               dev_err(kbc->dev,
+                       "Number of cols is more than supported by hardware\n");
+               return -EINVAL;
+       }
+
        for (i = 0; i < num_cols; i++) {
                kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
                kbc->pin_cfg[cols_cfg[i]].num = i;
        }
 
+       if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
+               dev_err(kbc->dev,
+                       "keypad rows/columns not properly specified\n");
+               return -EINVAL;
+       }
+
        return 0;
 }