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SubjectRe: [PATCH v4 2/3] i2c: Add driver for Cadence I2C controller
On Fri, 2014-04-04 at 04:38PM +0200, Wolfram Sang wrote:
> On Thu, Apr 03, 2014 at 10:59:26AM -0700, Soren Brinkmann wrote:
> > Add a driver for the Cadence I2C controller. This controller is for
> > example found in Xilinx Zynq.
> >
> > Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
> > Tested-by: Michal Simek <michal.simek@xilinx.com>
> > Reviewed-by: Harini Katakam <harinik@xilinx.com>
>
> Only minor stuff, but since you resend anyhow because of 400kHz issue...
>
> > +static void cdns_i2c_mrecv(struct cdns_i2c *id)
> > +{
> > + unsigned int ctrl_reg;
> > + unsigned int isr_status;
> > +
> > + id->p_recv_buf = id->p_msg->buf;
> > + id->recv_count = id->p_msg->len;
> > +
> > + /* Put the controller in master receive mode and clear the FIFO */
> > + ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
> > + ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO;
> > +
> > + if ((id->p_msg->flags & I2C_M_RECV_LEN) == I2C_M_RECV_LEN)
>
> 'if (id->p_msg->flags & I2C_M_RECV_LEN)' is enough.
>
> > + /* Report the other error interrupts to application as EIO */
> > + if (id->err_status & (CDNS_I2C_IXR_RX_UNF |
> > + CDNS_I2C_IXR_TX_OVF |
> > + CDNS_I2C_IXR_RX_OVF |
> > + CDNS_I2C_IXR_NACK)) {
> > + cdns_i2c_master_reset(adap);
> > + return -EIO;
> > + }
>
> NACK is returned as -ENXIO. Check 'Documentation/i2c/fault-codes' for
> standard patterns. I'd think the rest is EIO, though.

Okay, I'll put this into the next version:
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 43af8c351c8b..63f3f03ecc9b 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -311,7 +311,7 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
ctrl_reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
ctrl_reg |= CDNS_I2C_CR_RW | CDNS_I2C_CR_CLR_FIFO;

- if ((id->p_msg->flags & I2C_M_RECV_LEN) == I2C_M_RECV_LEN)
+ if (id->p_msg->flags & I2C_M_RECV_LEN)
id->recv_count = I2C_SMBUS_BLOCK_MAX + 1;

/*
@@ -531,12 +531,13 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
if (ret)
return ret;

- /* Report the other error interrupts to application as EIO */
- if (id->err_status & (CDNS_I2C_IXR_RX_UNF |
- CDNS_I2C_IXR_TX_OVF |
- CDNS_I2C_IXR_RX_OVF |
- CDNS_I2C_IXR_NACK)) {
+ /* Report the other error interrupts to application */
+ if (id->err_status) {
cdns_i2c_master_reset(adap);
+
+ if (id->err_status & CDNS_I2C_IXR_NACK)
+ return -ENXIO;
+
return -EIO;
}
}
Thanks,
Sören


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