[Patch V5] i2c: imx: implement bus recovery

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

Hello,

On Mon, Sep 21, 2015 at 04:29:20AM +0000, Gao Pandy wrote:
> > On Fri, Sep 11, 2015 at 06:42:34PM +0800, Gao Pan wrote:
> > > V5:
> > >  -introduce a dedicated gpio state for bus recovery.
> > >  -assign adapter.bus_recovery_info after the two gpios were aquired
> > >   successfully.
> > 
> > You also do this if the gpios were not acquired successfully.
>  
> Thanks. If the gpios are not acquired successfully, the context goes
> to label clk_disable. So the assignment is skipped.
> Please see the following code.
> 
>       ......
>   
> 	if (IS_ERR(i2c_imx->pins.sda)) {
> 		ret = PTR_ERR(i2c_imx->pins.sda);
> 		goto clk_disable;
> 	}
> 	if (IS_ERR(i2c_imx->pins.scl)) {
> 		ret = PTR_ERR(i2c_imx->pins.scl);
> 		goto clk_disable;
> 	}
> 	
> 	i2c_imx->adapter.bus_recovery_info = &i2c_imx_bus_recovery_info;
> 
> 	......

Right, if devm_gpiod_get_optional returns an error probing fails and
everything is right. If however devm_gpiod_get_optional returns NULL
(i.e. the dt doesn't contain an scl-gpios property) you happily use them
even though gpio_set_value are stubs in this case.
 
> > IMHO pinctrl_lookup_state returning an error is enough to not try a
> > recovery.
>  
> Thanks, you are right. How about the following logic.
> 
> 	if (!(IS_ERR(i2c_imx->pinctrl_pins_default)) && !(IS_ERR(i2c_imx->pinctrl_pins_gpio))) {

After the ! you don't need a (, but apart from this the logic is fine.

>                 i2c_imx->pins.sda =
>                         devm_gpiod_get_optional(&pdev->dev, "sda-gpios", GPIOD_IN);
>                 i2c_imx->pins.scl =
>                         devm_gpiod_get_optional(&pdev->dev, "scl-gpios", GPIOD_IN);
> 
>                 if (IS_ERR(i2c_imx->pins.sda)) {
>                         ret = PTR_ERR(i2c_imx->pins.sda);
>                         goto clk_disable;
>                 }
> 
>                 if (IS_ERR(i2c_imx->pins.scl)) {
>                         ret = PTR_ERR(i2c_imx->pins.scl);
>                         goto clk_disable;
>                 }

As said above, here you need an

		if (i2c_imx->pins.scl && i2c_imx->pins.sda)
>                 i2c_imx->adapter.bus_recovery_info = &i2c_imx_bus_recovery_info;
> 	} 

Best regards
Uwe

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