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>

1 files changed, 19 insertions, 0 deletions

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)