How to use spi device from another kernel module?

[agnel.joel@gmail.com (Joel Fernandes)]

On Tue, Dec 6, 2016 at 11:42 AM, Ran Shalit <ranshalit@gmail.com> wrote:
> Hello,
>
> I have spi device which is registered using spi_register_board_info(),
> and I would like to get a pointer to this device in some other kernel module.
>
> Is there a simple way to get a pointer to pointer to a device , so
> that we can use it from other module ? (something like i2c_get_adapter
> for i2c)

Find out what's the SPI bus number (for the master) and the chip
select on that SPI master (for the SPI device)

Then you can use bus_for_each_device on spi_bus_type and find the
spi_device you're looking for. See the following code for an example
of how to use bus_for_each_device:

http://lxr.free-electrons.com/source/drivers/spi/spi.c#L524

In your check function, just make sure your spi->master->bus_num is
the bus you want and the spi->chip_select is the chip select
corresponding to the device you want. If both these conditions are
satisfied, there you have your spi_device.

HTH,

-Joel