On Sat, Oct 29, 2011 at 9:44 PM, Baruch Siach <[email protected]> wrote: > Hi Wayne, > > On Fri, Oct 28, 2011 at 02:06:16PM +0100, Wayne Tams wrote: >> Can I use GPIO pins on my i.mx53 for SPI chip select, I have found little >> on the web that can help me, I am hoping that it is straight-forward enough >> for me to implement it? Perhaps there is a macro that I can use in the >> spi_board_info structure that will let me declare the GPIO? > > If you are using the mainline kernel then the SPI driver > (drivers/spi/spi-imx.c) supports the use of GPIO lines for chip-select > exclusively. You can find an i.MX53 specific example in > arch/arm/mach-mx5/board-mx53_evk.c (look for the mx53_evk_spi_data struct). > This example demonstrate the use of two GPIOs for chip-select, but the list of > chip-selects can be longer.
That looks promising, I assume you mean that your quoted example makes use of the driver spi-imx? > > Since you appear to be using the Freescale supplied kernel (as I infer from > your previous question on this list), you are probably using different driver. > This driver (likely > http://opensource.freescale.com/git?p=imx/linux-2.6-imx.git;a=blob;f=drivers/spi/mxc_spi.c;h=8c722686a0e1a419b417c0e2f98a4d6f028cf02e;hb=a1cd8a787a18da69ac4e48cfc876623bd7323799) > does not support GPIOs for chip-select. I should of added that I am using a kernel from a BSP supplied by Emtrion, as you guessed correctly, it based on the Freescale kernel which uses the mxc_spi driver. > > Freescale seem to have abandoned their in-house non mainlined SPI driver in a > later version of their kernel (rel_imx_2.6.38_11.09.01 tag in > http://opensource.freescale.com/git) so you may want to update your kernel. I will have a look at how much of an impact using the mainlined kernel will have on the operation of my SoM. A little off topic, bearing in mind my inexperience with Linux, can I upgrade the kernel using git and will the differences between the mainlined and Emtrion kernel be highlighted? It is just that there could be some Emtrion kernel adds that I could miss which may impact my board operation, memory mapping etc. Just to summarise, are these the options available to me? If so I will figure out which method will be best for me to do: 1) Hack the existing mxc_spi driver and add support for GPIO chip-select 2) Upgrade the kernel to the latest mainlined version and use the spi-imx driver included in that 3) Hack the kernel to use the spi_imx driver already included in the BSP which has GPIO chip-select support 4) Update my BSP SPI driver to the mainlined version Thank you for your help Baruch (and Grant) much appreciated, > > baruch > > -- > ~. .~ Tk Open Systems > =}------------------------------------------------ooO--U--Ooo------------{= > - [email protected] - tel: +972.2.679.5364, http://www.tkos.co.il - > ------------------------------------------------------------------------------ Get your Android app more play: Bring it to the BlackBerry PlayBook in minutes. BlackBerry App World™ now supports Android™ Apps for the BlackBerry® PlayBook™. Discover just how easy and simple it is! http://p.sf.net/sfu/android-dev2dev _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
