On Wed, Dec 7, 2016 at 6:58 PM, Joel Fernandes <agnel.joel@gmail.com> wrote:
On Tue, Dec 6, 2016 at 11:02 PM, Greg KH <greg@kroah.com> wrote:
On Tue, Dec 06, 2016 at 09:12:24PM -0800, Joel Fernandes wrote:
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.
Eeek, no, please never do that, use the proper spi apis to get your needed device. They are there somewhere, using a "raw" bus_for_each_device is never the answer unless you are a bus and iterating over your own device list.
Yes I completely agree, maybe I assumed too much and thought he was trying to do this for some quick debugging from some kernel module, and was just looking for a quick and dirty way to get to a spi_device. Was not really suggesting this for production code. :)
You were actually Right... That's exactly what I wanted :) , so I probably will try to use your simple method. I think that for production , spidev shows a good example how to use spi as a char device: https://github.com/Xilinx/linux-xlnx/blob/master/drivers/spi/spidev.c Thanks! Ran
Regards, Joel
thanks,
greg k-h