V4L/DVB (6551): tda8290: rule out tda988x before detecting tda8290/tda8295

To ensure prevention of detecting a tda9885/6/7 as a tda8290 or tda8295, we
will rule out the tda988x before testing the tda8290 / tda8295 id registers.

We read 8 bytes from the chip.  If they are all equal, then it is not a
tda829x, or some other error has occurred.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/media/video/tda8290.c b/drivers/media/video/tda8290.c
index 18e6a09642fa..f0191babe40c 100644
--- a/drivers/media/video/tda8290.c
+++ b/drivers/media/video/tda8290.c
@@ -746,6 +746,22 @@ int tda829x_probe(struct tuner *t)
         unsigned char restore_9886[] = { 0x00, 0xd6, 0x30 };
         unsigned char addr_dto_lsb = 0x07;
         unsigned char data;
+#define PROBE_BUFFER_SIZE 8
+        unsigned char buf[PROBE_BUFFER_SIZE];
+        int i;
+
+        /* rule out tda9887, which would return the same byte repeatedly */
+        tuner_i2c_xfer_send(&i2c_props, soft_reset, 1);
+        tuner_i2c_xfer_recv(&i2c_props, buf, PROBE_BUFFER_SIZE);
+        for (i = 1; i < PROBE_BUFFER_SIZE; i++) {
+                if (buf[i] == buf[0])
+                        continue;
+                break;
+        }
+
+        /* all bytes are equal, not a tda829x - probably a tda9887 */
+        if (i == PROBE_BUFFER_SIZE)
+                return -ENODEV;
 
         if ((tda8290_probe(&i2c_props) == 0) ||
             (tda8295_probe(&i2c_props) == 0))