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V4L/DVB (13092): cx25840: Improvements to the cx23885/7/8 chip detection mechanism.

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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>
This commit is contained in:
Steven Toth 2009-09-27 15:54:47 -03:00 committed by Mauro Carvalho Chehab
parent c6b7053bbc
commit 8c2d7821d4
1 changed files with 18 additions and 3 deletions
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21
drivers/media/video/cx25840/cx25840-core.c
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@ -1598,14 +1598,29 @@ static u32 get_cx2388x_ident(struct i2c_client *client)
/* 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;
}