V4L/DVB (13092): cx25840: Improvements to the cx23885/7/8 chip detection mechanism.
The prior mechanism wasn't reliable with the cx23887. This new mechanism
tests correctly against cx23885, 7 and 8 based products.
Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c
index 56ead3d..904e9a5 100644
--- a/drivers/media/video/cx25840/cx25840-core.c
+++ b/drivers/media/video/cx25840/cx25840-core.c
@@ -1598,14 +1598,29 @@
/* Come out of digital power down */
cx25840_write(client, 0x000, 0);
+ /* Detecting whether the part is cx23885/7/8 is more
+ * difficult than it needs to be. No ID register. Instead we
+ * probe certain registers indicated in the datasheets to look
+ * for specific defaults that differ between the silicon designs. */
+
+ /* It's either 885/7 if the IR Tx Clk Divider register exists */
if (cx25840_read4(client, 0x204) & 0xffff) {
- /* IR Tx Clk Divider register exists; chip must be a CX23885 */
- ret = V4L2_IDENT_CX23885_AV;
+ /* CX23885 returns bogus repetitive byte values for the DIF,
+ * which doesn't exist for it. (Ex. 8a8a8a8a or 31313131) */
+ ret = cx25840_read4(client, 0x300);
+ if (((ret & 0xffff0000) >> 16) == (ret & 0xffff)) {
+ /* No DIF */
+ ret = V4L2_IDENT_CX23885_AV;
+ } else {
+ /* CX23887 has a broken DIF, but the registers
+ * appear valid (but unsed), good enough to detect. */
+ ret = V4L2_IDENT_CX23887_AV;
+ }
} else if (cx25840_read4(client, 0x300) & 0x0fffffff) {
/* DIF PLL Freq Word reg exists; chip must be a CX23888 */
ret = V4L2_IDENT_CX23888_AV;
} else {
- /* A CX23887 A/V core has neither IR nor DIF */
+ v4l_err(client, "Unable to detect h/w, assuming cx23887\n");
ret = V4L2_IDENT_CX23887_AV;
}