Re: [RESEND][PATCH] SPI: Add SPI driver for most known i.MX SoCs

[Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

On Mon, Jun 15, 2009 at 03:28:48PM +0200, Guennadi Liakhovetski wrote:
> Hi Sascha, David
> 
> On Tue, 12 May 2009, Sascha Hauer wrote:
> 
> > Hi all,
> > 
> > I got no comments the last time I sent this, here is an updated version
> > which now also works on i.MX35. Any input on this?
> 
> David, what's your take on this driver?
> 
> Sascha, haven't looked at or tested it at all, just one nitpick:
> 
> > 
> > Sascha
> > 
> > 
> > v2: Updated and tested on i.MX35
> > 
> > While there already is a SPI driver for i.MX1 in the tree there are
> > good reasons to replace it:
> > 
> > - The inkernel driver implements a full blown SPI driver, but
> >   the hardware can be fully supported using a bitbang driver.
> >   This greatly reduces the size and complexity of the driver.
> > - The inkernel driver only works on i.MX1 SoCs. Unfortunately
> >   Freescale decided to randomly mix the register bits for each
> >   new SoC, This is quite hard to handle with the current driver
> >   since it has register accesses in many places.
> > - The DMA API of the durrent driver is broken for arch-mx1 (as opposed
> >   to arch-imx) and nobody cared to fix it yet.
> > 
> > This driver has been tested on i.MX1/i.MX27/i.MX35 with an AT25 type
> > EEPROM and on i.MX27/i.MX31 with a Freescale MC13783 PMIC.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > ---
> >  arch/arm/plat-mxc/include/mach/spi.h |   27 ++
> >  drivers/spi/Kconfig                  |    7 +-
> >  drivers/spi/Makefile                 |    2 +-
> >  drivers/spi/mxc_spi.c                |  685 ++++++++++++++++++++++++++++++++++
> >  4 files changed, 717 insertions(+), 4 deletions(-)
> >  create mode 100644 arch/arm/plat-mxc/include/mach/spi.h
> >  create mode 100644 drivers/spi/mxc_spi.c
> > 
> > diff --git a/arch/arm/plat-mxc/include/mach/spi.h b/arch/arm/plat-mxc/include/mach/spi.h
> > new file mode 100644
> > index 0000000..08be445
> > --- /dev/null
> > +++ b/arch/arm/plat-mxc/include/mach/spi.h
> > @@ -0,0 +1,27 @@
> > +
> > +#ifndef __MACH_SPI_H_
> > +#define __MACH_SPI_H_
> > +
> > +/*
> > + * struct spi_imx_master - device.platform_data for SPI controller devices.
> > + * @chipselect: Array of chipselects for this master. Numbers >= 0 mean gpio
> > + *              pins, numbers < 0 mean internal CSPI chipselects according
> > + *              to MXC_SPI_CS(). Normally you want to use gpio based chip
> > + *              selects as the CSPI module tries to be intelligent about
> > + *              when to assert the chipselect: The CSPI module deasserts the
> > + *              chipselect once it runs out of input data. The other problem
> > + *              is that it is not possible to mix between high active and low
> > + *              active chipselects on one single bus using the internal
> > + *              chipselects. Unfortunately Freescale decided to put some
> > + *              chipselects on dedicated pins which are not usable as gpios,
> > + *              so we have to support the internal chipselects.
> > + * @num_chipselect: ARRAY_SIZE(chipselect)
> > + */
> > +struct spi_imx_master {
> > +	int	*chipselect;
> > +	int	num_chipselect;
> > +};
> > +
> > +#define MXC_SPI_CS(no)	((no) - 32)
> > +
> > +#endif /* __MACH_SPI_H_*/
> > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> > index 7c61251..6bb8e12 100644
> > --- a/drivers/spi/Kconfig
> > +++ b/drivers/spi/Kconfig
> > @@ -117,10 +117,11 @@ config SPI_GPIO
> >  	  speed with a custom version of this driver; see the source code.
> >  
> >  config SPI_IMX
> > -	tristate "Freescale iMX SPI controller"
> > -	depends on ARCH_MX1 && EXPERIMENTAL
> > +	tristate "Freescale iMX SPI controllers"
> > +	depends on ARCH_MXC
> > +	select SPI_BITBANG
> >  	help
> > -	  This enables using the Freescale iMX SPI controller in master
> > +	  This enables using the Freescale iMX SPI controllers in master
> >  	  mode.
> >  
> >  config SPI_LM70_LLP
> > diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> > index 5d04519..73b508b 100644
> > --- a/drivers/spi/Makefile
> > +++ b/drivers/spi/Makefile
> > @@ -17,7 +17,7 @@ obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
> >  obj-$(CONFIG_SPI_AU1550)		+= au1550_spi.o
> >  obj-$(CONFIG_SPI_BUTTERFLY)		+= spi_butterfly.o
> >  obj-$(CONFIG_SPI_GPIO)			+= spi_gpio.o
> > -obj-$(CONFIG_SPI_IMX)			+= spi_imx.o
> > +obj-$(CONFIG_SPI_IMX)			+= mxc_spi.o
> 
> You disable building spi_imx.o, but do not remove the .c?

ok, will redo this. I planned to remove the old driver in a seperate
patch.

Sascha

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