media: v4l: Add a helper for setting up link-frequencies control

Add a helper for obtaining supported link frequencies in form most drivers
need them. The result is a bitmap of supported controls.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index 273d83de2a8763..d34d210908d967 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -585,3 +585,50 @@ u32 v4l2_fraction_to_interval(u32 numerator, u32 denominator)
 	return denominator ? numerator * multiplier / denominator : 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_fraction_to_interval);
+
+int v4l2_link_freq_to_bitmap(struct device *dev, const u64 *fw_link_freqs,
+			     unsigned int num_of_fw_link_freqs,
+			     const s64 *driver_link_freqs,
+			     unsigned int num_of_driver_link_freqs,
+			     unsigned long *bitmap)
+{
+	unsigned int i;
+
+	*bitmap = 0;
+
+	if (!num_of_fw_link_freqs) {
+		dev_err(dev, "no link frequencies in firmware\n");
+		return -ENODATA;
+	}
+
+	for (i = 0; i < num_of_fw_link_freqs; i++) {
+		unsigned int j;
+
+		for (j = 0; j < num_of_driver_link_freqs; j++) {
+			if (fw_link_freqs[i] != driver_link_freqs[j])
+				continue;
+
+			dev_dbg(dev, "enabling link frequency %lld Hz\n",
+				driver_link_freqs[j]);
+			*bitmap |= BIT(j);
+			break;
+		}
+	}
+
+	if (!*bitmap) {
+		dev_err(dev, "no matching link frequencies found\n");
+
+		dev_dbg(dev, "specified in firmware:\n");
+		for (i = 0; i < num_of_fw_link_freqs; i++)
+			dev_dbg(dev, "\t%llu Hz\n", fw_link_freqs[i]);
+
+		dev_dbg(dev, "driver supported:\n");
+		for (i = 0; i < num_of_driver_link_freqs; i++)
+			dev_dbg(dev, "\t%lld Hz\n", driver_link_freqs[i]);
+
+		return -ENOENT;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_link_freq_to_bitmap);