input: matrix-keymap: Add function to read the new DT binding

We now have a binding which adds two parameters to the matrix keypad DT
node. This is separate from the GPIO-driven matrix keypad binding, and
unfortunately incompatible, since that uses row-gpios/col-gpios for the
row and column counts.

So the easiest option here is to provide a function for non-GPIO drivers
to use to decode the binding.

Note: We could in fact create an entirely separate structure to hold
these two fields, but it does not seem worth it, yet. If we have more
parameters then we can add this, and then refactor each driver to hold
such a structure.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com> (v2)
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

5 files changed, 54 insertions, 18 deletions

diff --git a/drivers/input/keyboard/lpc32xx-keys.c b/drivers/input/keyboard/lpc32xx-keys.c
index 1b8add6cfb9d..42181435fe67 100644
--- a/drivers/input/keyboard/lpc32xx-keys.c
+++ b/drivers/input/keyboard/lpc32xx-keys.c
@@ -144,12 +144,13 @@ static int lpc32xx_parse_dt(struct device *dev,
 {
 	struct device_node *np = dev->of_node;
 	u32 rows = 0, columns = 0;
+	int err;
 
-	of_property_read_u32(np, "keypad,num-rows", &rows);
-	of_property_read_u32(np, "keypad,num-columns", &columns);
-	if (!rows || rows != columns) {
-		dev_err(dev,
-			"rows and columns must be specified and be equal!\n");
+	err = matrix_keypad_parse_of_params(dev, &rows, &columns);
+	if (err)
+		return err;
+	if (rows != columns) {
+		dev_err(dev, "rows and columns must be equal!\n");
 		return -EINVAL;
 	}
 
diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
index e25b022692cd..1b289092f4e3 100644
--- a/drivers/input/keyboard/omap4-keypad.c
+++ b/drivers/input/keyboard/omap4-keypad.c
@@ -215,18 +215,12 @@ static int omap4_keypad_parse_dt(struct device *dev,
 				 struct omap4_keypad *keypad_data)
 {
 	struct device_node *np = dev->of_node;
+	int err;
 
-	if (!np) {
-		dev_err(dev, "missing DT data");
-		return -EINVAL;
-	}
-
-	of_property_read_u32(np, "keypad,num-rows", &keypad_data->rows);
-	of_property_read_u32(np, "keypad,num-columns", &keypad_data->cols);
-	if (!keypad_data->rows || !keypad_data->cols) {
-		dev_err(dev, "number of keypad rows/columns not specified\n");
-		return -EINVAL;
-	}
+	err = matrix_keypad_parse_of_params(dev, &keypad_data->rows,
+					    &keypad_data->cols);
+	if (err)
+		return err;
 
 	if (of_get_property(np, "linux,input-no-autorepeat", NULL))
 		keypad_data->no_autorepeat = true;
diff --git a/drivers/input/keyboard/tca8418_keypad.c b/drivers/input/keyboard/tca8418_keypad.c
index a34cc6714e5b..55c15304ddbc 100644
--- a/drivers/input/keyboard/tca8418_keypad.c
+++ b/drivers/input/keyboard/tca8418_keypad.c
@@ -288,8 +288,11 @@ static int tca8418_keypad_probe(struct i2c_client *client,
 		irq_is_gpio = pdata->irq_is_gpio;
 	} else {
 		struct device_node *np = dev->of_node;
-		of_property_read_u32(np, "keypad,num-rows", &rows);
-		of_property_read_u32(np, "keypad,num-columns", &cols);
+		int err;
+
+		err = matrix_keypad_parse_of_params(dev, &rows, &cols);
+		if (err)
+			return err;
 		rep = of_property_read_bool(np, "keypad,autorepeat");
 	}
 
diff --git a/drivers/input/matrix-keymap.c b/drivers/input/matrix-keymap.c
index 3ae496ea5fe6..619b3824563c 100644
--- a/drivers/input/matrix-keymap.c
+++ b/drivers/input/matrix-keymap.c
@@ -50,6 +50,25 @@ static bool matrix_keypad_map_key(struct input_dev *input_dev,
 }
 
 #ifdef CONFIG_OF
+int matrix_keypad_parse_of_params(struct device *dev,
+				  unsigned int *rows, unsigned int *cols)
+{
+	struct device_node *np = dev->of_node;
+
+	if (!np) {
+		dev_err(dev, "missing DT data");
+		return -EINVAL;
+	}
+	of_property_read_u32(np, "keypad,num-rows", rows);
+	of_property_read_u32(np, "keypad,num-columns", cols);
+	if (!*rows || !*cols) {
+		dev_err(dev, "number of keypad rows/columns not specified\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int matrix_keypad_parse_of_keymap(const char *propname,
 					 unsigned int rows, unsigned int cols,
 					 struct input_dev *input_dev)
diff --git a/include/linux/input/matrix_keypad.h b/include/linux/input/matrix_keypad.h
index 5f3aa6b11bfa..27e06acc509a 100644
--- a/include/linux/input/matrix_keypad.h
+++ b/include/linux/input/matrix_keypad.h
@@ -81,4 +81,23 @@ int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
 			       unsigned short *keymap,
 			       struct input_dev *input_dev);
 
+#ifdef CONFIG_OF
+/**
+ * matrix_keypad_parse_of_params() - Read parameters from matrix-keypad node
+ *
+ * @dev: Device containing of_node
+ * @rows: Returns number of matrix rows
+ * @cols: Returns number of matrix columns
+ * @return 0 if OK, <0 on error
+ */
+int matrix_keypad_parse_of_params(struct device *dev,
+				  unsigned int *rows, unsigned int *cols);
+#else
+static inline int matrix_keypad_parse_of_params(struct device *dev,
+				  unsigned int *rows, unsigned int *cols)
+{
+	return -ENOSYS;
+}
+#endif /* CONFIG_OF */
+
 #endif /* _MATRIX_KEYPAD_H */