Tool/software: Linux
Hello,
We need to do use mcbsp on Linux.
Is there any simple example demonstrating mcbsp with Linux ?
I couldn't find any.
Regards,
Ran
Ran,
What do you mean by "familiar with CCS demonstration of mcbsp in DM814x" ? If you ask me for official CCS DM814x McBSP demo, no I do not have such. We have some CCS based DM814x McBSP code in the link already provided, but it was defined by you as "shows nothing which can help". The owner of the code (HRi) state that this code work fine for him.
Regards,
Pavel
Ran,
Yes, there is polling mode support. Polling mode is easiest comparing with IRQ and DMA, so I would suggest you to start with it. Once ready you can proceed with IRQ and DMA.
The selection between polling mode (OMAP_MCBSP_POLL_IO) and IRQ mode (OMAP_MCBSP_IRQ_IO) is done in omap_mcbsp_set_io_type() function.
In mcbspc. IRQ mode is selected:
omap_mcbsp_probe()
/* Default I/O is IRQ based */
mcbsp->io_type = OMAP_MCBSP_IRQ_IO;
You can see how polling mode is done in dsp-clock.c
omap_mcbsp_set_io_type(MCBSP_ID(clk_id), OMAP_MCBSP_POLL_IO);
The functions used in polling mode are:
omap_mcbsp_pollwrite(id, buf)
omap_mcbsp_pollread(id, buf)
omap_mcbsp_spi_master_xmit_word_poll(id, word)
omap_mcbsp_spi_master_recv_word_poll(id, word)
See also the below e2e threads:
Regards,
Pavel
Ran,
Ran Shalit said:I have register mcbsp device, it seems to be registered ok:
from dmesg:
omap2_mcbsp_init....
omap_mcbsp_register_board_cfg
omap_mcbsp_init
ranran mcbsp probe pdata->phys_base 0x47000000
mcbsp finished ok!
I see you have the below error reported in the kernel:
omap_mcbsp_init
Error: Driver 'omap-mcbsp' is already registered, aborting...
Seems like mcbsp is registered two times, it is better to fix this.
Ran Shalit said:Then I insert module which only do tx poll, but it fails to do the write:
I would recommend you to implement init and probe functions in the out-of-tree module, see the below device driver as an example:
Ran Shalit said:omap-mcbsp omap-mcbsp.1: Could not write to McBSP1 Register
Can you trace at which line of code exactly this message is generated? At which McBSP register exactly your driver can not write?
Regards,
Pavel
Ran,
Ran Shalit said:for some reason the driver expects phy base to be 0x47000100 instead of 0x47000000....
This is common issue for some of the peripherals modules. We have the same issue with McSPI. In Linux driver we have base addr of 0x47000100 and register offset start from 0x0. While in documentation (datasheet, TRM) we have base address of 0x47000000 and register offset start from 0x100. At the end we have the same full address.
Ran Shalit said:Some of driver code is for omap2/omap3/omap4,
Do we need this code with ti81xx too ?
Yes, I think we need the same code as for omap4. See again my replay at the below link:
Regards,
Pavel
