Hi Mika,
In current driver implementation, I2c controller is enabled, then disabled every time inside i2c_dw_xfer. So I think the interrupt masking should be done inside i2c_dw_xfer_init, where the controller is enabled.
i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
...
/* start the transfers */
i2c_dw_xfer_init(dev);
...
/*
* We must disable the adapter before unlocking the &dev->lock mutex
* below. Otherwise the hardware might continue generating interrupts
* which in turn causes a race condition with the following transfer.
* Needs some more investigation if the additional interrupts are
* a hardware bug or this driver doesn't handle them correctly yet.
*/
__i2c_dw_enable(dev, false);
...
}
Thanks,
Wenkai
-----Original Message-----
From: Westerberg, Mika
Sent: Friday, April 04, 2014 11:16 AM
To: Du, Wenkai
Cc: linux-i2c@xxxxxxxxxxxxxxx; Wolfram Sang; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] i2c-designware: Mask interrupts during i2c controller enable
On Fri, Apr 04, 2014 at 08:05:23PM +0300, Du, Wenkai wrote:
> diff --git a/drivers/i2c/busses/i2c-designware-core.c
> b/drivers/i2c/busses/i2c-designware-core.c
> index 14c4b30..71a3fa9 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -417,6 +417,9 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
> */
> dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);
>
> + /* disable interrupts */
> + i2c_dw_disable_int(dev);
> +
Please move this to i2c_dw_init() as I previously commented. This can only happen once the controller comes out of reset (either boot, or resume from system sleep).
> /* Enable the adapter */
> __i2c_dw_enable(dev, true);
>
> --
> 1.7.9.5
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