MPC880: i2cer register says tx is done but tx buf descriptor is still ready

[DI BACCO ANTONIO - technolabs]

A porting of the driver included in kernel 2.4.

Here is an excerpt of the method to send bytes over the i2c bus:
________________________________________________________________________
  i2c->i2c_i2cmr = 0x00;	/* Disable I2C interupts */
  i2c->i2c_i2cer = 0xff;
  i2c->i2c_i2mod |= 1;	/* Enable */
  i2c->i2c_i2com |= 0x80;	/* Begin transmission */
  tmo = jiffies + 1*HZ;
  /* Busy wait, with a timeout */
  while(!(i2c->i2c_i2cer & 0x12 || time_after(jiffies, tmo)));
  

  if (signal_pending(current) || !tmo){
    force_close(algo_8xx_data);
    if (!tmo)
        printk("IIC write: timeout!\n");

    return -EIO;
  }

  if ((tbdf[0]->cbd_sc | tbdf[1]->cbd_sc) & BD_SC_NAK) {
      printk(KERN_INFO "IIC write; no ack\n");
      if (cpm_debug > 0)
        printk("tx0 sc %04x, tx1 sc %04x\n", tbdf[0]->cbd_sc,tbdf[1]->cbd_sc);
    
    return 0;
  }

  if ((tbdf[0]->cbd_sc | tbdf[1]->cbd_sc) & BD_SC_READY) {
      printk(KERN_INFO "IIC write; complete but tbuf ready\n");
      if (cpm_debug > 0)
        printk("tx0 sc %04x, tx1 sc %04x\n", tbdf[0]->cbd_sc,tbdf[1]->cbd_sc);

    return 0;
  }


-----Original Message-----
From: Jochen Friedrich [mailto:jochen at scram.de]
Sent: Sat 17/11/2007 19.32
To: DI BACCO ANTONIO - technolabs
Cc: linuxppc-embedded at ozlabs.org
Subject: Re: MPC880: i2cer register says tx is done but tx buf descriptor is still	ready
 
Hi Antonio,

> How could it be possible? It happens during the first i2c transactions
> and then no more. 
>   

What linux version? Which driver?

Thanks,
Jochen


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