gpio: Rework of_gpiochip_set_names() to use device property accessors

In order to use "gpio-line-names" property in systems not having DT as
their boot firmware, rework of_gpiochip_set_names() to use device property
accessors. This reworked function is placed in a separate file making it
clear it deals with universal device properties.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-devprop.c b/drivers/gpio/gpiolib-devprop.c
new file mode 100644
index 000000000000..17bfc41692ef
--- /dev/null
+++ b/drivers/gpio/gpiolib-devprop.c
@@ -0,0 +1,62 @@
+/*
+ * Device property helpers for GPIO chips.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+
+#include "gpiolib.h"
+
+/**
+ * devprop_gpiochip_set_names - Set GPIO line names using device properties
+ * @chip: GPIO chip whose lines should be named, if possible
+ *
+ * Looks for device property "gpio-line-names" and if it exists assigns
+ * GPIO line names for the chip. The memory allocated for the assigned
+ * names belong to the underlying firmware node and should not be released
+ * by the caller.
+ */
+void devprop_gpiochip_set_names(struct gpio_chip *chip)
+{
+	struct gpio_device *gdev = chip->gpiodev;
+	const char **names;
+	int ret, i;
+
+	ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+						NULL, 0);
+	if (ret < 0)
+		return;
+
+	if (ret != gdev->ngpio) {
+		dev_warn(chip->parent,
+			 "names %d do not match number of GPIOs %d\n", ret,
+			 gdev->ngpio);
+		return;
+	}
+
+	names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
+	if (!names)
+		return;
+
+	ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+						names, gdev->ngpio);
+	if (ret < 0) {
+		dev_warn(chip->parent, "failed to read GPIO line names\n");
+		kfree(names);
+		return;
+	}
+
+	for (i = 0; i < gdev->ngpio; i++)
+		gdev->descs[i].name = names[i];
+
+	kfree(names);
+}