Re: [PATCH v2 2/2] net: flexcan: add transceiver switch gpios support

[Dong Aisheng <aisheng.dong@freescale.com>]

On Thu, Jun 28, 2012 at 08:05:14PM +0800, Marc Kleine-Budde wrote:
> On 06/28/2012 01:46 PM, Shawn Guo wrote:
> > On Thu, Jun 28, 2012 at 07:33:28PM +0800, Dong Aisheng wrote:
> >>> +		phy_stby_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
> >>> +							"phy-standby-gpios",
> >>> +							0, &flags);
> >>> +		if (gpio_is_valid(phy_stby_gpio)) {
> >>> +			if (flags == OF_GPIO_ACTIVE_LOW)
> >>> +				phy_stby_high = false;
> >>> +			err = devm_gpio_request_one(&pdev->dev, phy_stby_gpio,
> >>> +						    GPIOF_DIR_OUT,
> >>> +						    "phy-standby");
> >>> +			if (err) {
> >>> +				dev_err(&pdev->dev,
> >>> +					"failed to request gpio %d: %d\n",
> >>> +					phy_stby_gpio, err);
> >>> +				goto failed_gpio;
> >> I checked mx28 evk, it seems the phy only has a STB gpio and shared by both CAN0&CAN1.
> >> I wonder the CAN1 probe may fail here.
> >>
> > It can be managed by dts.  Here is what I have in imx28-evk.dts, where
> > only can0 has phy-enable-gpios property.
> > 
> > 
> > 	can0: can@80032000 {
> > 		pinctrl-names = "default";
> > 		pinctrl-0 = <&can0_pins_a>;
> > 		phy-enable-gpios = <&gpio2 13 0>;
> > 		status = "okay";
> > 	};
> > 
> > 	can1: can@80034000 {
> > 		pinctrl-names = "default";
> > 		pinctrl-0 = <&can1_pins_a>;
> > 		status = "okay";
> > 	};
> 
> Will this work if can0 is down and can1 is up?
> 
> Can we abstract the transceiver power as a regulator? Or a clock? :P
> 
Hmm, it may not be a power.
For mx28evk, it's a STBY pin.
So it may hard to abstract it as a regulator or clock.

Regards
Dong Aisheng