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 <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

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

···
 #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>
···
 
 	struct regmap *regmap;
 	struct regmap *sram;
+	struct regmap *settings;
 
 	const struct fw_info *fw_info;
 	struct allegro_buffer firmware;
···
 		dev_err(&pdev->dev, "failed to init sram\n");
 		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)