On 10/11/11 06:59, Felipe Balbi wrote:
> Hi,
>
> On Tue, Nov 08, 2011 at 11:49:46AM +0100, Nikolaus Voss wrote:
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index e8a1852..fba6da6 100644
>> + ckdiv = 0;
>> + while (cdiv > 255) {
>> + ckdiv++;
>> + cdiv = cdiv >> 1;
>> + }
>> +
>> + if (cpu_is_at91rm9200() && (ckdiv > 5)) {
>> + dev_err(dev->dev, "AT91RM9200 Erratum #22: using ckdiv = 5.\n");
>
> is it really an error ? Or would it be enough as dev_dbg() ?
dev_warn is probably appropriate.
>
>> +static int at91_do_twi_transfer(struct at91_twi_dev *dev, bool is_read)
>> +{
>> + int ret;
>> +
>> + INIT_COMPLETION(dev->cmd_complete);
>> + if (is_read) {
>> + if (!dev->buf_len)
>> + at91_twi_write(dev, AT91_TWI_CR,
>> + AT91_TWI_START | AT91_TWI_STOP);
>> + else
>> + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_START);
>> + at91_twi_write(dev, AT91_TWI_IER,
>> + AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
>> + } else {
>> + at91_twi_write_next_byte(dev);
>> + at91_twi_write(dev, AT91_TWI_IER,
>> + AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
>> + }
>> +
>> + ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
>> + dev->adapter.timeout);
>> + if (ret == 0) {
>> + dev_err(dev->dev, "controller timed out\n");
>> + at91_init_twi_bus(dev);
>> + return -ETIMEDOUT;
>> + }
>> + if (dev->transfer_status & AT91_TWI_NACK) {
>> + dev_dbg(dev->dev, "received nack\n");
>> + return -ENODEV;
>
> not sure error code matches here. If the HW replies with NACK you tell
> your users there's no I2C adapter ? Sounds a bit weird to me...
I think -ENODEV was used because a NACK can mean that there is no device
at the address you are trying to talk to. Other drivers appear to use
-EIO or -EREMOTEIO. The latter is possibly more correct.
~Ryan
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