drm/komeda: Add ACLK rate to sysfs

Expose node with the name 'aclk_hz'
Signed-off-by: Mihail Atanassov <mihail.atanassov@arm.com>
Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Ayan kumar halder <ayan.halder@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190828110342.45936-1-mihail.atanassov@arm.com

drivers/gpu/drm/arm/display/komeda/komeda_dev.c

@@ -91,9 +91,19 @@ config_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR_RO(config_id);
 
+static ssize_t
+aclk_hz_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct komeda_dev *mdev = dev_to_mdev(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%lu\n", clk_get_rate(mdev->aclk));
+}
+static DEVICE_ATTR_RO(aclk_hz);
+
 static struct attribute *komeda_sysfs_entries[] = {
 	&dev_attr_core_id.attr,
 	&dev_attr_config_id.attr,
+	&dev_attr_aclk_hz.attr,
 	NULL,
 };