gumstix

Hi Scott,

As I have spent some time getting SPI to work by following various bits 
of info scattered around the web, I would welcome your proposed patch. 
It should help save lots of time for beginners and people unfamiliar 
with SPI.

Regards,
Markus.


On 2010.12.10 15:13, ScottEllis wrote:
> I'd like to propose this patch to board-overo.c
>
> diff --git git/arch/arm/mach-omap2/board-overo.c
> git/arch/arm/mach-omap2/board-overo.c
> index 95efc77..315daa7 100644
> --- git/arch/arm/mach-omap2/board-overo.c
> +++ git/arch/arm/mach-omap2/board-overo.c
> @@ -628,6 +628,14 @@ static struct spi_board_info overo_spi_board_info[]
> __initdata = {
>   		.irq			= OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
>   		.platform_data		=&ads7846_config,
>   	},
> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
> +	{
> +		.modalias		= "spidev",
> +		.bus_num		= 1,
> +		.chip_select		= 0,
> +		.max_speed_hz		= 48000000,
> +		.mode			= SPI_MODE_0,
> +	},
>   #endif
>   #if defined(CONFIG_PANEL_LGPHILIPS_LB035Q02) || \
>   	defined(CONFIG_PANEL_LGPHILIPS_LB035Q02_MODULE)
> @@ -638,6 +646,14 @@ static struct spi_board_info overo_spi_board_info[]
> __initdata = {
>   		.max_speed_hz		= 500000,
>   		.mode			= SPI_MODE_3,
>   	},
> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
> +	{
> +		.modalias		= "spidev",
> +		.bus_num		= 1,
> +		.chip_select		= 1,
> +		.max_speed_hz		= 48000000,
> +		.mode			= SPI_MODE_0,
> +	},
>   #endif
>   };
>
>
> This would allow enabling of spidev on either CS0 or CS1 with only a kernel
> defconfig change and rebuild rather then a board-overo.c change with the
> added
> steps that a patch involves when using OE.
>
> It also eliminates the question for new users on where and what changes are
> needed to enable or customize spidev.
>
> The change does not impact current behavior since both ADS7846 and
> LGPHILIPS_LB035Q02 are enabled in the default defconfig, as is SPI_SPIDEV.
>
>
> With this patch in place, the instructions for enabling spidev would be
>
> (to enable spidev on SPI1.CS0)
>
> sed -i 's:CONFIG_TOUCHSCREEN_ADS7846=m:# CONFIG_TOUCHSCREEN_ADS7846 is not
> set:g' defconfig
>
> (to enable spidev on SPI1.CS1)
>
> sed -i 's:CONFIG_PANEL_LGPHILIPS_LB035Q02=y:# #
> CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set:g' defconfig
>
>
> And then a kernel rebuild.
>
> Those sed lines could incorporated into a patch or a recipe (like the
> MUSB_MODE),
> but the core idea is that users would not have to mess with board-overo.c
> unless
> the spi_board_info needed modifications. In which case this change still
> helps
> because it directs users to where they should edit.
>
> Thoughts?

Rethinking this a little, a slower speed then 48MHz is probably more useful.

Maybe 1 or 2 MHz would be a better default.


ScottEllis wrote:
> 
> I'd like to propose this patch to board-overo.c
> 
> diff --git git/arch/arm/mach-omap2/board-overo.c
> git/arch/arm/mach-omap2/board-overo.c
> index 95efc77..315daa7 100644
> --- git/arch/arm/mach-omap2/board-overo.c
> +++ git/arch/arm/mach-omap2/board-overo.c
> @@ -628,6 +628,14 @@ static struct spi_board_info overo_spi_board_info[]
> __initdata = {
>  		.irq			= OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
>  		.platform_data		= &ads7846_config,
>  	},
> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
> +	{
> +		.modalias		= "spidev",
> +		.bus_num		= 1,
> +		.chip_select		= 0,
> +		.max_speed_hz		= 48000000,
> +		.mode			= SPI_MODE_0,
> +	},
>  #endif
>  #if defined(CONFIG_PANEL_LGPHILIPS_LB035Q02) || \
>  	defined(CONFIG_PANEL_LGPHILIPS_LB035Q02_MODULE)
> @@ -638,6 +646,14 @@ static struct spi_board_info overo_spi_board_info[]
> __initdata = {
>  		.max_speed_hz		= 500000,
>  		.mode			= SPI_MODE_3,
>  	},
> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
> +	{
> +		.modalias		= "spidev",
> +		.bus_num		= 1,
> +		.chip_select		= 1,
> +		.max_speed_hz		= 48000000,
> +		.mode			= SPI_MODE_0,
> +	},
>  #endif
>  };
> 
> 
> This would allow enabling of spidev on either CS0 or CS1 with only a
> kernel 
> defconfig change and rebuild rather then a board-overo.c change with the
> added 
> steps that a patch involves when using OE.
> 
> It also eliminates the question for new users on where and what changes
> are
> needed to enable or customize spidev.
> 
> The change does not impact current behavior since both ADS7846 and 
> LGPHILIPS_LB035Q02 are enabled in the default defconfig, as is SPI_SPIDEV.
> 
> 
> With this patch in place, the instructions for enabling spidev would be
> 
> (to enable spidev on SPI1.CS0)
> 
> sed -i 's:CONFIG_TOUCHSCREEN_ADS7846=m:# CONFIG_TOUCHSCREEN_ADS7846 is not
> set:g' defconfig
> 
> (to enable spidev on SPI1.CS1)
> 
> sed -i 's:CONFIG_PANEL_LGPHILIPS_LB035Q02=y:# #
> CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set:g' defconfig
> 
> 
> And then a kernel rebuild.
> 
> Those sed lines could incorporated into a patch or a recipe (like the
> MUSB_MODE), 
> but the core idea is that users would not have to mess with board-overo.c
> unless 
> the spi_board_info needed modifications. In which case this change still
> helps
> because it directs users to where they should edit.
> 
> Thoughts?
> 

-- 
View this message in context: http://old.nabble.com/Patch-to-simplify-spidev-enabling-tp30429646p30430010.html
Sent from the Gumstix mailing list archive at Nabble.com.

+1
Going to have to support students(undergrad and post grad) using spi on
overo(tobi) next semester and this would help a lot.

They'll be using spi for a few sensors and sparkfun led matrix displays(4
-8 daisy chained).

They have to get spi working themselves.


Alex

> Hi Scott,
>
> As I have spent some time getting SPI to work by following various bits
> of info scattered around the web, I would welcome your proposed patch.
> It should help save lots of time for beginners and people unfamiliar
> with SPI.
>
> Regards,
> Markus.
>
>
> On 2010.12.10 15:13, ScottEllis wrote:
>> I'd like to propose this patch to board-overo.c
>>
>> diff --git git/arch/arm/mach-omap2/board-overo.c
>> git/arch/arm/mach-omap2/board-overo.c
>> index 95efc77..315daa7 100644
>> --- git/arch/arm/mach-omap2/board-overo.c
>> +++ git/arch/arm/mach-omap2/board-overo.c
>> @@ -628,6 +628,14 @@ static struct spi_board_info overo_spi_board_info[]
>> __initdata = {
>>   		.irq			= OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
>>   		.platform_data		=&ads7846_config,
>>   	},
>> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
>> +	{
>> +		.modalias		= "spidev",
>> +		.bus_num		= 1,
>> +		.chip_select		= 0,
>> +		.max_speed_hz		= 48000000,
>> +		.mode			= SPI_MODE_0,
>> +	},
>>   #endif
>>   #if defined(CONFIG_PANEL_LGPHILIPS_LB035Q02) || \
>>   	defined(CONFIG_PANEL_LGPHILIPS_LB035Q02_MODULE)
>> @@ -638,6 +646,14 @@ static struct spi_board_info overo_spi_board_info[]
>> __initdata = {
>>   		.max_speed_hz		= 500000,
>>   		.mode			= SPI_MODE_3,
>>   	},
>> +#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
>> +	{
>> +		.modalias		= "spidev",
>> +		.bus_num		= 1,
>> +		.chip_select		= 1,
>> +		.max_speed_hz		= 48000000,
>> +		.mode			= SPI_MODE_0,
>> +	},
>>   #endif
>>   };
>>
>>
>> This would allow enabling of spidev on either CS0 or CS1 with only a
>> kernel
>> defconfig change and rebuild rather then a board-overo.c change with the
>> added
>> steps that a patch involves when using OE.
>>
>> It also eliminates the question for new users on where and what changes
>> are
>> needed to enable or customize spidev.
>>
>> The change does not impact current behavior since both ADS7846 and
>> LGPHILIPS_LB035Q02 are enabled in the default defconfig, as is
>> SPI_SPIDEV.
>>
>>
>> With this patch in place, the instructions for enabling spidev would be
>>
>> (to enable spidev on SPI1.CS0)
>>
>> sed -i 's:CONFIG_TOUCHSCREEN_ADS7846=m:# CONFIG_TOUCHSCREEN_ADS7846 is
>> not
>> set:g' defconfig
>>
>> (to enable spidev on SPI1.CS1)
>>
>> sed -i 's:CONFIG_PANEL_LGPHILIPS_LB035Q02=y:# #
>> CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set:g' defconfig
>>
>>
>> And then a kernel rebuild.
>>
>> Those sed lines could incorporated into a patch or a recipe (like the
>> MUSB_MODE),
>> but the core idea is that users would not have to mess with
>> board-overo.c
>> unless
>> the spi_board_info needed modifications. In which case this change still
>> helps
>> because it directs users to where they should edit.
>>
>> Thoughts?
>
> ------------------------------------------------------------------------------
> Oracle to DB2 Conversion Guide: Learn learn about native support for
> PL/SQL,
> new data types, scalar functions, improved concurrency, built-in packages,
> OCI, SQL*Plus, data movement tools, best practices and more.
> http://p.sf.net/sfu/oracle-sfdev2dev
> _______________________________________________
> gumstix-users mailing list
> gumstix-users@...
> https://lists.sourceforge.net/lists/listinfo/gumstix-users
>

Hi Scott,

On Fri, Dec 10, 2010 at 12:13 PM, ScottEllis
<scottellis.developer@...> wrote:
> (to enable spidev on SPI1.CS1)
>
> sed -i 's:CONFIG_PANEL_LGPHILIPS_LB035Q02=y:# #
> CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set:g' defconfig
This seems like an interesting idea.
Couple things:
- is it valuable to have options for both on spi 1.0 & spi 1.1 or is
that just a potential point of confusion for user trying to make this
work?  I suspect few people use palo35 boards with the 3.5" screen so
1.1 would likely be a good choice.
- with your patches to 2.6.34, it is possible to instantiate a spi
device on the fly without modifying board-overo.  Admittedly, this
would require changes to the spidev files.  Could this approach work
and are there any advantages?

Just thinking aloud here.
-Ash

Hi Ash,

I think SPI 1.0 and SPI 1.1 are equally useful. There is no change to the
default behavior for either CS line
with the patch, so no harm. I would advocate for both. It allows for more
then one SPI device. I think it is
okay to require a little understanding from the user enabling SPIDEV.

Yes, you can now add OMAP SPI devices dynamically without board file
changes. There were a couple of 
small omap2_mcspi driver changes required, but now it works fine for custom
drivers on OMAP3's at least. 
I personally think it simplifies driver development. It minimizes kernel
rebuilds at least. Maybe no one else 
cares though, since it was never quite finished for the OMAPs.

SPIDEV is used with platforms that use different SPI controllers. Since I
only have OMAP3 devices to test
with, I am hesitant to post patches to mainline for SPIDEV for fear of
breaking existing users.

I don't know how great the need is either. I was doing some SPI
documentation and thought I would add
something about SPIDEV for completeness. I've never used SPIDEV myself. Just
loaded the module. ;-) 

Custom SPI drivers are pretty easy and what I've always done.

To elaborate on the user instructions with this patch, it would be

sed -i 's:CONFIG_TOUCHSCREEN_ADS7846=m:# CONFIG_TOUCHSCREEN_ADS7846 is not
set:g' defconfig

to enable SPIDEV on SPI 1.0

sed -i 's:CONFIG_PANEL_LGPHILIPS_LB035Q02=y:#
CONFIG_PANEL_LGPHILIPS_LB035Q02 is not set:g' defconfig

to enable enable SPIDEV on SPI 1.1

and finally, either or both of the above along with this

sed -i 's:CONFIG_SPI_SPIDEV=y:# CONFIG_SPI_SPIDEV is not set:g' defconfig

to free the respective CS lines for a custom SPI driver that was doing
dynamic configuration.

And then a kernel rebuild of course.

-- 
View this message in context: http://old.nabble.com/Patch-to-simplify-spidev-enabling-tp30429646p30432513.html
Sent from the Gumstix mailing list archive at Nabble.com.