Re: [patch 3/3] i2c: add support for i2c bus on Freescale CPM1/CPM2 controllers

[Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

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On Wed, May 14, 2008 at 04:14:45PM -0700, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org wrote:

I just managed to test the latest version of this driver.

> +static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
> +{
> +	struct cpm_i2c *cpm = i2c_get_adapdata(adap);
> +	struct i2c_reg __iomem *i2c_reg = cpm->i2c_reg;
> +	struct i2c_ram __iomem *i2c_ram = cpm->i2c_ram;
> +	struct i2c_msg *pmsg;
> +	int ret, i;
> +	int tptr;
> +	int rptr;
> +	cbd_t __iomem *tbdf;
> +	cbd_t __iomem *rbdf;
> +
> +	if (num > CPM_MAXBD)
> +		return -EINVAL;
> +
> +	/* Check if we have any oversized READ requests */
> +	for (i = 0; i < num; i++) {
> +		pmsg = &msgs[i];
> +		if (pmsg->len >= CPM_MAX_READ)
> +			return -EINVAL;
> +	}
> +
> +	/* Reset to use first buffer */
> +	out_be16(&i2c_ram->rbptr, in_be16(&i2c_ram->rbase));
> +	out_be16(&i2c_ram->tbptr, in_be16(&i2c_ram->tbase));
> +
> +	tbdf = cpm->tbase;
> +	rbdf = cpm->rbase;
> +
> +	tptr = 0;
> +	rptr = 0;
> +
> +	while (tptr < num) {
> +		pmsg = &msgs[tptr];
> +		dev_dbg(&adap->dev, "R: %d T: %d\n", rptr, tptr);
> +
> +		cpm_i2c_parse_message(adap, pmsg, num, tptr, rptr);
> +		if (pmsg->flags & I2C_M_RD)
> +			rptr++;
> +		tptr++;
> +	}
> +	/* Start transfer now */
> +	/* Enable RX/TX/Error interupts */
> +	out_8(&i2c_reg->i2cmr, I2CER_BUSY | I2CER_TXB | I2CER_RXB);
> +	out_8(&i2c_reg->i2cer, 0xff);	/* Clear interrupt status */
> +	/* Chip bug, set enable here */
> +	setbits8(&i2c_reg->i2mod, I2MOD_EN);	/* Enable */
> +	/* Begin transmission */
> +	setbits8(&i2c_reg->i2com, I2COM_MASTER);
Bummer! This should not be I2COM_MASTER but I2COM_START! Otherwise no
I2C communication will happen.

After applying this change, the driver works fine on an MPC8260 (like
the previous version did).

All the best,

   Wolfram

-- 
  Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry

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