On Mon, Dec 03, 2012 at 08:24:05AM +0530, Viresh Kumar wrote:
> Add bus recovery support for designware_i2c controller. It uses generic gpio
> based i2c_gpio_recover_bus() routine. Platforms need to pass struct
> i2c_bus_recovery_info as platform data designware I2C controller.
> 
> Signed-off-by: Vincenzo Frascino <[email protected]>
> Signed-off-by: Shiraz Hashim <[email protected]>
> Signed-off-by: Viresh Kumar <[email protected]>
> ---
> V7->V8:
> - Removed setting clock_rate_khz.
> 
>  drivers/i2c/busses/i2c-designware-core.c    |  6 +++++-
>  drivers/i2c/busses/i2c-designware-platdrv.c | 17 +++++++++++++++--
>  2 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-core.c 
> b/drivers/i2c/busses/i2c-designware-core.c
> index cbba7db..24feaaf 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -538,7 +538,11 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg 
> msgs[], int num)
>       ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
>       if (ret == 0) {
>               dev_err(dev->dev, "controller timed out\n");
> -             i2c_dw_init(dev);
> +             if (adap->bus_recovery_info) {
> +                     dev_dbg(dev->dev, "try i2c bus recovery\n");
> +                     adap->bus_recovery_info->recover_bus(adap);
> +             }
> +

I think we need something like i2c_recover_bus in the core which does
the above and also returns the return code from recover_bus. If there is
no recover_bus it should return EOPNOTSUPP.

Then the driver can do

        ret = i2c_recover_bus(adap);
        if (ret < 0)
                i2c_dw_init();

If not calling i2c_dw_init, you will probably cause a regression.

>               ret = -ETIMEDOUT;
>               goto done;
>       } else if (ret < 0)
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c 
> b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 0506fef..8c44eb9 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -55,6 +55,7 @@ static int __devinit dw_i2c_probe(struct platform_device 
> *pdev)
>       struct dw_i2c_dev *dev;
>       struct i2c_adapter *adap;
>       struct resource *mem, *ioarea;
> +     struct i2c_bus_recovery_info *recovery_info;
>       int irq, r;
>  
>       /* NOTE: driver uses the static register mapping */
> @@ -141,17 +142,27 @@ static int __devinit dw_i2c_probe(struct 
> platform_device *pdev)
>       adap->dev.parent = &pdev->dev;
>       adap->dev.of_node = pdev->dev.of_node;
>  
> +     /* Bus recovery support */
> +     recovery_info = dev_get_platdata(&pdev->dev);
> +     if (recovery_info) {
> +             recovery_info->recover_bus = i2c_generic_gpio_recovery;
> +             adap->bus_recovery_info = recovery_info;
> +     } else {
> +             adap->bus_recovery_info = NULL;
> +     }
> +

Please post the platform patch next time, too. Then I can get a better
understanding...

>       adap->nr = pdev->id;
>       r = i2c_add_numbered_adapter(adap);
>       if (r) {
>               dev_err(&pdev->dev, "failure adding adapter\n");
> -             goto err_free_irq;
> +             goto err_free_recovery_info;
>       }
>       of_i2c_register_devices(adap);
>  
>       return 0;
>  
> -err_free_irq:
> +err_free_recovery_info:
> +     kfree(recovery_info);

... because I am wondering about the kfree here.

>       free_irq(dev->irq, dev);
>  err_iounmap:
>       iounmap(dev->base);
> @@ -174,6 +185,8 @@ static int __devexit dw_i2c_remove(struct platform_device 
> *pdev)
>       struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
>       struct resource *mem;
>  
> +     kfree(dev->adapter.bus_recovery_info);
> +
>       platform_set_drvdata(pdev, NULL);
>       i2c_del_adapter(&dev->adapter);
>       put_device(&pdev->dev);
> -- 
> 1.7.12.rc2.18.g61b472e
> 
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