Hi Wolfram,
On Tue, Jul 31, 2018 at 10:09:32PM +0200, Wolfram Sang wrote:
> Hi Manivannan,
>
> On Thu, Jul 26, 2018 at 09:16:02PM +0530, Manivannan Sadhasivam wrote:
> > Add Actions Semiconductor Owl family S900 I2C driver.
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > Acked-by: Peter Rosin <peda@xxxxxxxxxx>
>
> Looks mostly good already. Thanks Peter for the initial review!
>
Thanks to Andy also :)
> > +static irqreturn_t owl_i2c_interrupt(int irq, void *_dev)
> > +{
> > + struct owl_i2c_dev *i2c_dev = _dev;
> > + struct i2c_msg *msg = i2c_dev->msg;
> > + unsigned long flags;
> > + unsigned int stat, fifostat;
> > +
> > + spin_lock_irqsave(&i2c_dev->lock, flags);
> > +
> > + fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT);
> > + if (fifostat & OWL_I2C_FIFOSTAT_RNB) {
> > + dev_dbg(&i2c_dev->adap.dev, "received NACK from device\n");
> > + goto stop;
> > + }
> > +
> > + stat = readl(i2c_dev->base + OWL_I2C_REG_STAT);
> > + if (stat & OWL_I2C_STAT_BEB) {
> > + dev_dbg(&i2c_dev->adap.dev, "bus error\n");
> > + goto stop;
> > + }
>
> I wonder if you can't pass back the different errors to the upper
> layers? Like -ENXIO for NACK and -EIO for bus error? We have a
> convention for that and it seems your HW can support it. The different
> error codes would then maybe also make the debug outputs obsolete.
>
>
Sure, will catch the errors using an i2c_dev member and pass it to upper
layers in owl_i2c_master_xfer.
> > + /*
> > + * Here, -ENXIO will be returned if interrupt occurred but no
> > + * read or write happened. Else if msg_ptr equals to message length,
> > + * message count will be returned.
> > + */
> > + ret = i2c_dev->msg_ptr == msg->len ? num : -ENXIO;
>
> I'd think this kinda unusual construct could go then as well by just
> returning the error code derived from the interrupt handler above.
>
Makes sense! It will become:
ret = i2c_dev->err < 0 ? i2c_dev->err : num;
Thanks,
Mani
> > +static const struct i2c_adapter_quirks owl_i2c_quirks = {
> > + .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST,
> > + .max_read_len = 240,
> > + .max_write_len = 240,
> > + .max_comb_1st_msg_len = 6,
> > + .max_comb_2nd_msg_len = 240,
> > +};
>
> Yay! Good use of the i2c_adapter_quirks struct :)
>
> Regards,
>
> Wolfram
>
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