Re: [PATCH v4 2/3] i2c: iproc: Add Broadcom iProc I2C Driver

Uwe Kleine-König
2015-01-17T16:01:51Z

Hello,

On Fri, Jan 16, 2015 at 02:09:28PM -0800, Ray Jui wrote:
> On 1/15/2015 12:41 AM, Uwe Kleine-König wrote:
> > On Wed, Jan 14, 2015 at 02:23:32PM -0800, Ray Jui wrote:
> >> + */
> >> + val = 1 << M_CMD_START_BUSY_SHIFT;
> >> + if (msg->flags & I2C_M_RD) {
> >> + val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) |
> >> + (msg->len << M_CMD_RD_CNT_SHIFT);
> >> + } else {
> >> + val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT);
> >> + }
> >> + writel(val, iproc_i2c->base + M_CMD_OFFSET);
> >> +
> >> + time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left);
> >
> > When the interrupt fires here after the complete timed out and before
> > you disable the irq you still throw the result away.
> Yes, but then this comes down to the fact that if it has reached the
> point that is determined to be a timeout condition in the driver, one
> should really treat it as timeout error. In a normal condition,
> time_left should never reach zero.
I don't agree here. I'm not sure there is a real technical reason,
though. But still if you're in a "success after timeout already over"
situation it's IMHO better to interpret it as success, not timeout.

> >> +static int bcm_iproc_i2c_remove(struct platform_device *pdev)
> >> +{
> >> + struct bcm_iproc_i2c_dev *iproc_i2c = platform_get_drvdata(pdev);
> >> +
> >> + i2c_del_adapter(&iproc_i2c->adapter);
> > You need to free the irq before i2c_del_adapter.
> >
> Yes. Thanks. Change back to use devm_request_irq, and use disable_irq
> here before removing the adapter.
The more lightweight approach is to set your device's irq-enable
register to zero and call synchronize_irq. (For a shared irq calling
disable_irq is even wrong here.)

Best regards
Uwe

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