[U-Boot] PPC4XX Custom Board - Failing to read I2C
Stefan Roese
sr at denx.de
Fri Apr 5 08:04:54 CEST 2013
On 05.04.2013 02:04, txcotrader wrote:
> After looking deeper I've found a difference in register values when
> performing drivers/i2c/ppc4xx_i2c.c->i2c_transfer function.
>
> v1.7.02 code yields:
>
> /* Transfer is in progress
> * we have to wait for upto 5 bytes of data
> * 1 byte chip address+r/w bit then bc bytes
> * of data.
> * udelay(10) is 1 bit time at 100khz
> * Doubled for slop. 20 is too small.
> */
> i = 2*5*8;
> do {
> /* Get status */
> status = in_8((u8 *)IIC_STS);
> printf("gd_ do status->i = %d, status = %d\n", i, status);
> udelay(20);
> i--;
> } while ((status & IIC_STS_PT) && !(status & IIC_STS_ERR) && (i >
> 0));
>
> gd_ do status->i = 80, status = 40
>
>
> v2013.01.01 Yields:
> i = 2 * 5 * 8;
> do {
> /* Get status */
> status = in_8(&i2c->sts);
> printf("gd_ do status->i = %d, status = %d\n", i, status);
> udelay(10);
> i--;
> } while ((status & IIC_STS_PT) && !(status & IIC_STS_ERR) &&
> (i > 0));
>
> gd_ do status->i = 80, status = 40
>
> v1.7.02 - include/4xx_i2c.h:#define IIC_STS
> (I2C_REGISTERS_BASE_ADDRESS+IICSTS)
> v2013.01.01 - struct ppc4xx_i2c *i2c = (struct ppc4xx_i2c *)I2C_BASE_ADDR;
>
> Newb question, but I should be able to add an offset to correct this issue
> right?
The resulting addresses should be the same. The old version uses the
offset via a define and the new one the (recommended) struct access to
the register. I suggest you print the resulting address to verify that
it really is the same.
Thanks,
Stefan
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