Improve VIDIOC_G_CHIP_IDENT (better diagnostics)

From: Hans Verkuil <hverkuil@xs4all.nl>

Simplify the VIDIOC_G_CHIP_IDENT implementation by adding a single
common function. The ident can now also return NONE: not found, UNKNOWN:
found, but we don't know what chip it is, and AMBIGUOUS: multiple
chips were matched so the match values were too general.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

5 files changed, 22 insertions, 36 deletions

diff --git a/linux/drivers/media/video/cx25840/cx25840-core.c b/linux/drivers/media/video/cx25840/cx25840-core.c
index d5a0789bc..c401c1ee7 100644
--- a/linux/drivers/media/video/cx25840/cx25840-core.c
+++ b/linux/drivers/media/video/cx25840/cx25840-core.c
@@ -840,15 +840,7 @@ static int cx25840_command(struct i2c_client *client, unsigned int cmd,
 		break;
 
 	case VIDIOC_G_CHIP_IDENT:
-	{
-		struct v4l2_chip_ident *chip = arg;
-
-		if (!v4l2_chip_match_i2c_client(client, chip->match_type, chip->match_chip))
-			return -EINVAL;
-		chip->ident = state->id;
-		chip->revision = state->rev;
-		break;
-	}
+		return v4l2_chip_ident_i2c_client(client, arg, state->id, state->rev);
 
 	default:
 		return -EINVAL;
diff --git a/linux/drivers/media/video/ov7670.c b/linux/drivers/media/video/ov7670.c
index d68f36851..b033bf334 100644
--- a/linux/drivers/media/video/ov7670.c
+++ b/linux/drivers/media/video/ov7670.c
@@ -1316,15 +1316,7 @@ static int ov7670_command(struct i2c_client *client, unsigned int cmd,
 {
 	switch (cmd) {
 	case VIDIOC_G_CHIP_IDENT:
-	{
-		struct v4l2_chip_ident *chip = arg;
-
-		if (!v4l2_chip_match_i2c_client(client, chip->match_type, chip->match_chip))
-			return -EINVAL;
-		chip->ident = V4L2_IDENT_OV7670;
-		chip->revision = 0;
-		return 0;
-	}
+		return v4l2_chip_ident_i2c_client(client, arg, V4L2_IDENT_OV7670, 0);
 
 	case VIDIOC_INT_RESET:
 		ov7670_reset(client);
diff --git a/linux/drivers/media/video/saa7115.c b/linux/drivers/media/video/saa7115.c
index 8b4abb3a1..064a81334 100644
--- a/linux/drivers/media/video/saa7115.c
+++ b/linux/drivers/media/video/saa7115.c
@@ -1449,15 +1449,7 @@ static int saa711x_command(struct i2c_client *client, unsigned int cmd, void *ar
 #endif
 
 	case VIDIOC_G_CHIP_IDENT:
-	{
-		struct v4l2_chip_ident *chip = arg;
-
-		if (!v4l2_chip_match_i2c_client(client, chip->match_type, chip->match_chip))
-			return -EINVAL;
-		chip->ident = state->ident;
-		chip->revision = 0;
-		break;
-	}
+		return v4l2_chip_ident_i2c_client(client, arg, state->ident, 0);
 
 	default:
 		return -EINVAL;
diff --git a/linux/drivers/media/video/saa7127.c b/linux/drivers/media/video/saa7127.c
index 28306f15d..185eb7e9d 100644
--- a/linux/drivers/media/video/saa7127.c
+++ b/linux/drivers/media/video/saa7127.c
@@ -664,15 +664,7 @@ static int saa7127_command(struct i2c_client *client,
 	}
 
 	case VIDIOC_G_CHIP_IDENT:
-	{
-		struct v4l2_chip_ident *chip = arg;
-
-		if (!v4l2_chip_match_i2c_client(client, chip->match_type, chip->match_chip))
-			return -EINVAL;
-		chip->ident = state->ident;
-		chip->revision = 0;
-		break;
-	}
+		return v4l2_chip_ident_i2c_client(client, arg, state->ident, 0);
 
 	default:
 		return -EINVAL;
diff --git a/linux/drivers/media/video/v4l2-common.c b/linux/drivers/media/video/v4l2-common.c
index 60c56a8b0..0a45e19cb 100644
--- a/linux/drivers/media/video/v4l2-common.c
+++ b/linux/drivers/media/video/v4l2-common.c
@@ -60,6 +60,7 @@
 #include <linux/video_decoder.h>
 #define __OLD_VIDIOC_ /* To allow fixing old calls*/
 #include <media/v4l2-common.h>
+#include <media/v4l2-chip-ident.h>
 
 #ifdef CONFIG_KMOD
 #include <linux/kmod.h>
@@ -1605,6 +1606,22 @@ int v4l2_chip_match_i2c_client(struct i2c_client *c, u32 match_type, u32 match_c
 	}
 }
 
+int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_chip_ident *chip,
+		u32 ident, u32 revision)
+{
+	if (!v4l2_chip_match_i2c_client(c, chip->match_type, chip->match_chip))
+		return 0;
+	if (chip->ident == V4L2_IDENT_NONE) {
+		chip->ident = ident;
+		chip->revision = revision;
+	}
+	else {
+		chip->ident = V4L2_IDENT_AMBIGUOUS;
+		chip->revision = 0;
+	}
+	return 0;
+}
+
 int v4l2_chip_match_host(u32 match_type, u32 match_chip)
 {
 	switch (match_type) {
@@ -1639,6 +1656,7 @@ EXPORT_SYMBOL(v4l2_ctrl_query_fill);
 EXPORT_SYMBOL(v4l2_ctrl_query_fill_std);
 
 EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
+EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
 EXPORT_SYMBOL(v4l2_chip_match_host);
 
 /*