From mboxrd@z Thu Jan  1 00:00:00 1970
From: s.hauer@pengutronix.de (Sascha Hauer)
Date: Wed, 2 Mar 2011 14:51:36 +0100
Subject: [PATCH] ARM: mxs/mx28evk: add flexcan devices
In-Reply-To: <20110302125525.GD21601@S2100-06.ap.freescale.net>
References: <1299063284-21795-1-git-send-email-shawn.guo@freescale.com>
	<20110302111148.GV29521@pengutronix.de>
	<20110302114549.GC21601@S2100-06.ap.freescale.net>
	<20110302125525.GD21601@S2100-06.ap.freescale.net>
Message-ID: <20110302135136.GA29521@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wed, Mar 02, 2011 at 08:55:25PM +0800, Shawn Guo wrote:
> On Wed, Mar 02, 2011 at 07:45:50PM +0800, Shawn Guo wrote:
> > On Wed, Mar 02, 2011 at 12:11:48PM +0100, Sascha Hauer wrote:
> > > Hi Shawn,
> > > 
> > Hi Sascha,
> > 
> > > On Wed, Mar 02, 2011 at 06:54:44PM +0800, Shawn Guo wrote:
> > > > Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
> > > > ---
> > > >  arch/arm/mach-mxs/Kconfig        |    1 +
> > > >  arch/arm/mach-mxs/mach-mx28evk.c |   37 +++++++++++++++++++++++++++++++++++++
> > > >  2 files changed, 38 insertions(+), 0 deletions(-)
> > > > 
> > > > diff --git a/arch/arm/mach-mxs/Kconfig b/arch/arm/mach-mxs/Kconfig
> > > > index 55bf075..9a1f2cb 100644
> > > > --- a/arch/arm/mach-mxs/Kconfig
> > > > +++ b/arch/arm/mach-mxs/Kconfig
> > > > @@ -31,6 +31,7 @@ config MACH_MX28EVK
> > > >  	select MXS_HAVE_AMBA_DUART
> > > >  	select MXS_HAVE_PLATFORM_AUART
> > > >  	select MXS_HAVE_PLATFORM_FEC
> > > > +	select MXS_HAVE_PLATFORM_FLEXCAN
> > > >  	select MXS_OCOTP
> > > >  	default y
> > > >  	help
> > > > diff --git a/arch/arm/mach-mxs/mach-mx28evk.c b/arch/arm/mach-mxs/mach-mx28evk.c
> > > > index 1f0b708..3cefb73 100644
> > > > --- a/arch/arm/mach-mxs/mach-mx28evk.c
> > > > +++ b/arch/arm/mach-mxs/mach-mx28evk.c
> > > > @@ -28,6 +28,7 @@
> > > >  #include "devices-mx28.h"
> > > >  #include "gpio.h"
> > > >  
> > > > +#define MX28EVK_FLEXCAN_SWITCH	MXS_GPIO_NR(2, 13)
> > > >  #define MX28EVK_FEC_PHY_POWER	MXS_GPIO_NR(2, 15)
> > > >  #define MX28EVK_FEC_PHY_RESET	MXS_GPIO_NR(4, 13)
> > > >  
> > > > @@ -95,6 +96,15 @@ static const iomux_cfg_t mx28evk_pads[] __initconst = {
> > > >  	/* phy reset line */
> > > >  	MX28_PAD_ENET0_RX_CLK__GPIO_4_13 |
> > > >  		(MXS_PAD_4MA | MXS_PAD_3V3 | MXS_PAD_NOPULL),
> > > > +
> > > > +	/* flexcan0 */
> > > > +	MX28_PAD_GPMI_RDY2__CAN0_TX,
> > > > +	MX28_PAD_GPMI_RDY3__CAN0_RX,
> > > > +	/* flexcan1 */
> > > > +	MX28_PAD_GPMI_CE2N__CAN1_TX,
> > > > +	MX28_PAD_GPMI_CE3N__CAN1_RX,
> > > > +	/* transceiver power control */
> > > > +	MX28_PAD_SSP1_CMD__GPIO_2_13,
> > > >  };
> > > >  
> > > >  /* fec */
> > > > @@ -178,8 +188,28 @@ error:
> > > >  	return -ETIMEDOUT;
> > > >  }
> > > >  
> > > > +/* flexcan */
> > > > +static void mx28evk_flexcan_switch(int enable)
> > > > +{
> > > > +	static int count;
> > > > +
> > > > +	if (enable) {
> > > > +		if (!count++)
> > > > +			gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 1);
> > > > +	} else {
> > > > +		if (!--count)
> > > > +			gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 0);
> > > > +	}
> > > > +}
> > > 
> > > Why this count variable? It shouldn't hurt to call gpio_set_value
> > > multiple times.
> > > 
> Something like this?
> 
> /*
>  * On mx28evk board, two flexcan transceivers are controlled
>  * by one power switch gpio.
>  */
> #define FLEXCAN0_SWITCH_ON	(1 << 0)
> #define FLEXCAN1_SWITCH_ON	(1 << 1)
> 
> static int flexcan_switch_on;
> 
> static void mx28evk_flexcan0_switch(int enable)
> {
> 	if (enable) {
> 		flexcan_switch_on |= FLEXCAN0_SWITCH_ON;
> 		gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 1);
> 	} else {
> 		flexcan_switch_on &= ~FLEXCAN0_SWITCH_ON;
> 		if (!flexcan_switch_on)
> 			gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 0);
> 	}
> }
> 
> static void mx28evk_flexcan1_switch(int enable)
> {
> 	if (enable) {
> 		flexcan_switch_on |= FLEXCAN1_SWITCH_ON;
> 		gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 1);
> 	} else {
> 		flexcan_switch_on &= ~FLEXCAN1_SWITCH_ON;
> 		if (!flexcan_switch_on)
> 			gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 0);
> 	}
> }
> 
> static const struct flexcan_platform_data
> 		mx28evk_flexcan_pdata[] __initconst = {
> 	{
> 		.transceiver_switch = mx28evk_flexcan0_switch,
> 	}, {
> 		.transceiver_switch = mx28evk_flexcan1_switch,
> 	}
> };

More like this, which is slightly easier to read, but the effect is the
same.

static int flexcan0_en, flexcan0_en;

/*
 * MX28EVK_FLEXCAN_SWITCH is shared between both can controllers
 */
static void mx28evk_flexcan_switch(void)
{
	if (flexcan0_en || flexcan1_en)
		gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 1);
	else
		gpio_set_value(MX28EVK_FLEXCAN_SWITCH, 0);
}

static void mx28evk_flexcan0_switch(int enable)
{
	flexcan0_en = enable;
	mx28evk_flexcan_switch();
}

static void mx28evk_flexcan1_switch(int enable)
{
	flexcan1_en = enable;
	mx28evk_flexcan_switch();
}

static const struct flexcan_platform_data
                mx28evk_flexcan_pdata[] __initconst = {
        {
                .transceiver_switch = mx28evk_flexcan0_switch,
        }, {
                .transceiver_switch = mx28evk_flexcan1_switch,
        }
};

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