From mboxrd@z Thu Jan  1 00:00:00 1970
From: aisheng.dong@freescale.com (Dong Aisheng)
Date: Thu, 28 Jun 2012 20:02:46 +0800
Subject: [PATCH v2 2/2] net: flexcan: add transceiver switch gpios support
In-Reply-To: <20120628114815.GL6406@shlinux2.ap.freescale.net>
References: <1340853701-4488-1-git-send-email-shawn.guo@linaro.org>
 <1340853701-4488-3-git-send-email-shawn.guo@linaro.org>
 <20120628113327.GJ6406@shlinux2.ap.freescale.net>
 <20120628114559.GE22990@S2101-09.ap.freescale.net>
 <20120628114815.GL6406@shlinux2.ap.freescale.net>
Message-ID: <20120628120245.GM6406@shlinux2.ap.freescale.net>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Thu, Jun 28, 2012 at 07:48:16PM +0800, Dong Aisheng wrote:
> On Thu, Jun 28, 2012 at 07:46:02PM +0800, 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 at 80032000 {
> > 		pinctrl-names = "default";
> > 		pinctrl-0 = <&can0_pins_a>;
> > 		phy-enable-gpios = <&gpio2 13 0>;
> > 		status = "okay";
> > 	};
> > 
> > 	can1: can at 80034000 {
> > 		pinctrl-names = "default";
> > 		pinctrl-0 = <&can1_pins_a>;
> > 		status = "okay";
> > 	};
> Yes, that is a solution.
> But it may not so reasonable since dts file should represent hw, but here
> we have to do some trick by we know how driver works.
> Maybe we need find a better solution.
> 
One more thing, for such dt representation, if can0 phy is disabled,
can1 may be disabled wrongly too, right?

Regards
Dong Aisheng