Jan Kiszka wrote:
Wolfgang Grandegger wrote:
Hi Matthias,
Matthias Fuchs wrote:
Hi,
attached you will find a patch that adds support for memory mapped
SJA1000 CAN controllers as they often can be found on embedded boards.
The driver is based on the rtmen_isa driver.
What about using request_mem_region()?
(and this would also give RTCAN_DRV_NAME some sense again :))
While looking to the driver I now
realize, that it's mainly duplicated code. Does it not make more sense
to make a combined io/mem driver. If io address < 32K it's an io driver
else a mem driver.
And provide two sets of readreg/writereg? What about differences in
Yes.
chip->irq_flags, are they always like io=edge, mem=level? What about
defaults for CDR and OCR? Are the arbitrary anyway or do they correlate
somehow to the access type?
Another module parameter for the irq_flags makes sense, indeed. OCR and
CDR do not affect the access type. It more defines some electrical
characteristics.
/* Output control register */
enum SJA1000_PELI_OCR {
SJA_OCR_MODE_BIPHASE = 0,
SJA_OCR_MODE_TEST = 1,
SJA_OCR_MODE_NORMAL = 2,
SJA_OCR_MODE_CLOCK = 3,
SJA_OCR_TX0_INVERT = 1<<2,
SJA_OCR_TX0_PULLDOWN = 1<<3,
SJA_OCR_TX0_PULLUP = 2<<3,
SJA_OCR_TX0_PUSHPULL = 3<<3,
SJA_OCR_TX1_INVERT = 1<<5,
SJA_OCR_TX1_PULLDOWN = 1<<6,
SJA_OCR_TX1_PULLUP = 2<<6,
SJA_OCR_TX1_PUSHPULL = 3<<6
};
enum SJA1000_PELI_CDR {
SJA_CDR_CLK_OFF = 1<<3, /* Clock off (CLKOUT pin) */
SJA_CDR_CBP = 1<<6, /* CAN input comparator bypass */
SJA_CDR_CAN_MODE = 1<<7 /* CAN mode: 1 = PeliCAN */
};
When we do not find answers right now (maybe in other Linux CAN
stacks?), we may postpone the merge and keep is separated until more
hardware pops up with more use-cases.
No hurry, of course.
The driver has been tested on esd's embedded PowerPC boards with AMCC
PPC405 CPUs.
Thanks to Jan for giving me some introduction to Xenomai during a
nightly session last friday.
There's one thing a I am not very satisfied with :-) Why passing half
of the external clock frequency to the module. Because of compatiblity
reasons I kept this behavior of the clock paramter from the ISA driver.
The attached patch fixes this and replaces the module parameter "isa"
with "io". I also tend to rename the driver into rtcan_io instead
rtcan_isa if we keep it.
Wolfgang.
Jan
Wolfgang.
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