Zampieron, Jeffrey a écrit :
Hi,
Interesting question about the DM355 CCDC Driver...
Using LSP 0802106 with MVL5.
Why does the CCDC reset function have a mdelay( 5 ) in the register init
loop?
You should be able to 0 registers at full-core speed without
consequence.
*snip*
void ccdc_reset()
{
int i, memctrl, clkctrl;
/* disable CCDC */
dev_dbg(vpfe_dev, "\nStarting ccdc_reset...");
ccdc_enable(0);
/* set all registers to default value */
for (i = 0; i <= 0x15c; i += 4) {
//- JZ why is this here, that's about a 435 ms wait???
mdelay( 5 );
regw(0, i);
}
*snap*
I didn't see any documentation in the VPFE docs, spruf71, about a timing
constraint. I can't capture video without that delay in there so there
clearly is something important about it.
Also checked the mailing list archive. No dice either.
Thoughts, tips, ideas all welcome... There are delays littered about the
driver with no comments about why. The DM6446 driver does similar
operations but does not have the same mdelays.
Is there hardware errata hiding here?
I asked the same question without any answer.
However, the driver code that was proposed for review does not have this
delay anymore, but an explanation would be welcome
-JZ
---------------------------------------
Jeffrey Zampieron
Software Engineer
Harris Corporation
RF Division
Sensor Systems Group
Phone: 585-720-8533
Email: [email protected]
---------------------------------------
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