SPI trouble on Colibri 270 (PXA)...

[Eric Miao]

On Wed, Apr 21, 2010 at 5:44 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
> Dne Út 20. dubna 2010 17:20:37 Jakob Viketoft napsal(a):
>> Eric Miao wrote:
>> > On Tue, Apr 20, 2010 at 7:58 PM, Jakob Viketoft <jakob at viketoft.se> wrote:
>> <...>
>>
>> >> I haven't seen any other board using the same combination (the m25p80
>> >> and the pxa2xx), but I'm still opting for an error on my part
>> >> somewhere. I've attached my SPI configuration (board setup) in the end
>> >> of the mail.
>> >
>> > Not looked into m25p80 code, but CS is normally asserted before a
>> > transfer begins and deasserted after a transfer is done. I doubt there
>> > are some cases where the transfer is not set up correctly.
>>
>> Well, in this case when doing a read you must set up a write transfer to
>> write the read command + address and then a read transfer to actually
>> read back the data. In this case the cs musn't be deasserted between
>> transfers because this means the operation is terminated.
>>
>> > Actually, cs_assert() and cs_deassert() are there in pxa2xx_spi.c as two
>> > very good debugging point to print out the transfer information to see
>> > if they are setup correctly.
>>
>> When I look at how these two are used I get a an serie of assert,
>> assert, deassert for each read operation (which should be correct
>> behaviour). This suggests that something else is deasserting the cs or
>> that the CPU is doing something on it's own accord. Hmmm...
>>
>> Regards,
>>
>>       /Jakob
>>
>
> You can try using gpio-spi driver as used in palmz72.c ... I had issues with
> pxa2xx-spi interfacing the OV96xx camera, but it worked well for me with gpio-
> spi.
>
> Looking at it now, it seems the patch was never merged, here's a shortened
> version, try something similar:
>
> From 777212ce6d3bacea76281aa3d74839a3c38b32a4 Mon Sep 17 00:00:00 2001
> From: Marek Vasut <marek.vasut at gmail.com>
> Date: Sat, 22 Aug 2009 05:15:10 +0200
> Subject: [PATCH 3/3] PalmZ72: Add support for OV9640 camera sensor
>
> Signed-off-by: Marek Vasut <marek.vasut at gmail.com>
> ---
>  arch/arm/mach-pxa/include/mach/palmz72.h |    5 +
>  arch/arm/mach-pxa/palmz72.c              |  126
> +++++++++++++++++++++++++++++-
>  2 files changed, 130 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-pxa/palmz72.c b/arch/arm/mach-pxa/palmz72.c
> index c3645aa..e4449ad 100644
> --- a/arch/arm/mach-pxa/palmz72.c
> +++ b/arch/arm/mach-pxa/palmz72.c
> @@ -30,6 +30,7 @@
>  #include <linux/wm97xx_batt.h>
>  #include <linux/power_supply.h>
>  #include <linux/usb/gpio_vbus.h>
> +#include <linux/i2c-gpio.h>
>
>  #include <asm/mach-types.h>
>  #include <asm/mach/arch.h>
> @@ -120,6 +123,28 @@ static unsigned long palmz72_pin_config[] __initdata = {
>        GPIO22_GPIO,    /* LCD border color */
>        GPIO96_GPIO,    /* lcd power */
>
> +       /* I2C */
> +       GPIO117_GPIO,   /* I2C_SCL */
> +       GPIO118_GPIO,   /* I2C_SDA */
>
> +static struct i2c_gpio_platform_data palmz72_i2c_bus_data = {
> +       .sda_pin = 118,
> +       .scl_pin = 117,
> +       .udelay  = 10,
> +       .timeout = 100,
> +};
> +
> +static struct platform_device palmz72_i2c_bus_device = {
> +       .name           = "i2c-gpio",
> +       .id             = 0, /* we use this as a replacement for i2c-pxa */
> +       .dev = {
> +               .platform_data = &palmz72_i2c_bus_data,
> +       }
> +};
>

I thought we were talking about SPI?