On Tue, Oct 27, 2009 at 12:04 PM, Oliver Hartkopp
<[email protected]> wrote:
> Hello Christian,
Hi,
> Before connecting Kontron i just wanted to ask you, if there's already a
> working SPI driver that would be able to connect your mcp251x driver with the
> parallel port analogue to the MicroChip eval board???
the SPI master driver and the mcp251x should be independent of each
other, but unfortunately on the x86 things tend to be a lot messier (I
dream of a world without x86 and windoze ;-) ). Personally I always
used this CAN chip on ARM platforms with native SPI (not big-banging).
I had a quick look at the driver you cited and it looks like it's
rather ad-hoc because it plays some strange tricks with the driver
subsystem:
/*
* The modalias name MUST match the device_driver name
* for the bus glue code to match and subsequently bind them.
* We are binding to the generic drivers/hwmon/lm70.c device
* driver.
*/
strcpy(pp->info.modalias, "lm70");
I think that if you don't load "lm70" driver it will be ok anyway, it
looks like the spi master driver just grabs the first parport it's
offered. You can check /sys/bus/spi if you have a SPI bus after
loading parport.ko, parport_pc.ko and spi_lm70llp.ko.
Next you should bind the mcp251x driver to the bus with
spi_register_board_info.
static struct mcp251x_platform_data mcp251x_info = {
.oscillator_frequency = 8000000,
.board_specific_setup = NULL,
.model = CAN_MCP251X_MCP2515,
.power_enable = NULL,
.transceiver_enable = NULL,
};
static struct spi_board_info spi_board_info[] = {
{
.modalias = "mcp251x",
.platform_data = &mcp251x_info,
.irq = 7, /* or 5, grepping for FLOPPY_IRQ
gave me an idea how irqs work on x86 */
.max_speed_hz = 2*1000*1000,
.chip_select = 0, /* is supports just the one CS */
},
};
I would put this in a module by itself with spi_register_board_info
for the testing. In this module I'll call parport_enable_irq to
enable IRQ register. When loading parport_pc pass -1 to the interrupt
number so there won't be problem with sharing that. Of course this
assumes that the mcp2515 interrupt line is connected to the parallel
port that generates interrupts.
Hope this help, I'll never tried it out but this is the way I'll try
to approach the problem. Let me know if it works or I can help you in
some way.
--
Christian Pellegrin, see http://www.evolware.org/chri/
"Real Programmers don't play tennis, or any other sport which requires
you to change clothes. Mountain climbing is OK, and Real Programmers
wear their climbing boots to work in case a mountain should suddenly
spring up in the middle of the computer room."
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