[Spca50x-devs] autodetection of the sensors fails on freedata autodetection of the sensors fails on freedata WS-620E

["Stefan Hartsuiker" <sahartsu@xxxxxxxxx>]

Hi,

Srivas may be on to something, because it solved my problem with the
autodetection of the sensor.

With kind regards,

Stefan Hartsuiker

-- Orignal Message --
Date: Mon, 24 Jul 2006 19:29:47 +0530
From: <srivas.ramgopal@xxxxxxxxx>
Subject: Re: [Spca50x-devs] Unable to see picture using Phillips
        SPC200NC        webcam
To: <spca5xx@xxxxxxxxxxxxxxx>
Cc: spca50x-devs@xxxxxxxxxxxxxxxxxxxxx
Message-ID:
        <5DE86B4C624D4545B8A5CA1467DB936402FA0B17@xxxxxxxxxxxxxxxxxxxxxxx>
Content-Type: text/plain;        charset="us-ascii"

Hi,

Thanks for your prompt response.  The kernel version I'm using is
2.6.15.4.  I have a different OHCI driver, because this is a PCMCIA
card.  Hence I cannot use the standard OHCI dirver, which is PCI-based.
Now the only difference between these two drivers is that the one I am
using sends an interrupt earlier than the standard PCI-based driver i.e.
an interrupt is sent before 1ms in my case.

Due to this difference, I added a delay of 1 ms between two
spca5xxRegReads and between one spca5xxRegRead and spca5xxRegWrite in
the functions, zcxx_i2cRead and zcxx_i2cWrite.  After making this
change, the spca5xx driver behaves properly, by detecting the correct
sensor and retrieving the correct capablities of the webcam, and I am
able to see the picture using spcaview.  Following is the code snippet
of the same.

static __u16 zcxx_i2cRead(struct usb_device *dev, __u8 reg)
{
    __u8 retbyte = 0;
    __u8 retval[] = { 0, 0 };

    spca5xxRegWrite(dev, 0xa0, reg, 0x92, NULL, 0);
    spca5xxRegWrite(dev, 0xa0, 0x02, 0x90, NULL, 0);        // <-read
command
    wait_ms(1); // 1 ms delay added
    spca5xxRegRead(dev, 0xa1, 0x01, 0x0091, &retbyte, 1);        // read
status
    wait_ms(1); // 1 ms delay added
    spca5xxRegRead(dev, 0xa1, 0x01, 0x0095, &retval[0], 1);        // read
Lowbyte
    wait_ms(1); // 1 ms delay added
    spca5xxRegRead(dev, 0xa1, 0x01, 0x0096, &retval[1], 1);        // read
Hightbyte
    return ((retval[1] << 8) | retval[0]);
}

static __u8 zcxx_i2cWrite(struct usb_device *dev, __u8 reg, __u8 valL,
                          __u8 valH)
{
    __u8 retbyte = 0;
    spca5xxRegWrite(dev, 0xa0, reg, 0x92, NULL, 0);
    spca5xxRegWrite(dev, 0xa0, valL, 0x93, NULL, 0);
    spca5xxRegWrite(dev, 0xa0, valH, 0x94, NULL, 0);
    spca5xxRegWrite(dev, 0xa0, 0x01, 0x90, NULL, 0);        // <-write
command
    wait_ms(1); // 1 ms delay added
    spca5xxRegRead(dev, 0xa1, 0x01, 0x0091, &retbyte, 1);        // read
status
    return (retbyte);
}

Does this webcam require some kind of delay for between register
read/write operations?

Regards,
-Srivas


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