media: allegro: lookup VCU settings

The VCU provides information about its configuration in a dedicated
register space. These settings include, for example, the expected clock
rates and the configuration of the encoder buffer. In the device tree,
the settings are described by the "xlnx,vcu-settings" compatible.

The settings are needed to correctly configure the clocks and the
encoder buffer.

Lookup the VCU settings in the device tree and make it accessible to the
driver via a regmap.
Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/platform/allegro-dvt/allegro-core.c

@@ -12,6 +12,8 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/log2.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/xlnx-vcu.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -136,6 +138,7 @@ struct allegro_dev {
 
 	struct regmap *regmap;
 	struct regmap *sram;
+	struct regmap *settings;
 
 	const struct fw_info *fw_info;
 	struct allegro_buffer firmware;
@@ -3721,6 +3724,10 @@ static int allegro_probe(struct platform_device *pdev)
 		return PTR_ERR(dev->sram);
 	}
 
+	dev->settings = syscon_regmap_lookup_by_compatible("xlnx,vcu-settings");
+	if (IS_ERR(dev->settings))
+		dev_warn(&pdev->dev, "failed to open settings\n");
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;