My problem is I have an 1553 chip (an avionic data bus) connected to the
HPS master (an ARM processor) via an FPGA (soft) SPI controller. This is
where the spi-altera.c comes in. It provides the driver/interface to the
soft SPI controller on the Arria 10 SoC.
I need an interface now to communicate between the SPI slave (the 1553
chip) and the SPI master (the Arria 10 HPS/ARM).
When I load _spi-altera.ko_ I get the _udev_ files (_/dev/spidevXX_) but
not when I load _spidev.ko._ Why? _spi-altera.c _doesn't have an _init_
routine and consequently no call to _register_chrdev_(..) but _spidev.c_
does. What's the relationship between _spi-altera_ and _spidev_? What's
the purpose of _spi.c_?
On 2021-03-20 18:14, jchludzinski wrote:
How is it possible to build a loadable module from _spi-altera.c_ when
it has no code for creating _udev_ files (i.e., _/dev/spidevXX_); it
has no:
static int __init spidev_init(void)
{
int status;
printk(KERN_ALERT "DEBUG: Passed %s %d \n", __FUNCTION__,
__LINE__);
/* Claim our 256 reserved device numbers. Then register a class
* that will key udev/mdev to add/remove /dev nodes. Last,
register
* the driver which manages those device numbers.
*/
BUILD_BUG_ON(N_SPI_MINORS > 256);
status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops);
printk(KERN_ALERT "DEBUG: Passed %s %d \n", __FUNCTION__,
__LINE__);
if (status < 0)
return status;
printk(KERN_ALERT "DEBUG: Passed %s %d \n", __FUNCTION__,
__LINE__);
spidev_class = class_create(THIS_MODULE, "spidev");
if (IS_ERR(spidev_class)) {
unregister_chrdev(SPIDEV_MAJOR,
spidev_spi_driver.driver.name);
return PTR_ERR(spidev_class);
}
printk(KERN_ALERT "DEBUG: Passed %s %d \n", __FUNCTION__,
__LINE__);
status = spi_register_driver(&spidev_spi_driver);
if (status < 0) {
class_destroy(spidev_class);
unregister_chrdev(SPIDEV_MAJOR,
spidev_spi_driver.driver.name);
}
printk(KERN_ALERT "DEBUG: Passed %s %d \n", __FUNCTION__,
__LINE__);
return status;
}
module_init(spidev_init);
The _printk_'s are of course mine.
---John
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