how to get or initialize clock in L4Linux

Yunchuan Geng yunchuan.geng at
Fri Aug 8 12:33:34 CEST 2014

Hi Martin,

Thanks for the response.

First I do not know how to do it from U-Boot. But I found it might 
better to do it in mach_setup.c where  l4x_arm_devices_init() is called.

However, I checked the implementation of native linux, it use Device 
Tree Blob to feed initialize process with data. It would be great if I 
could load dtb into L4Linux too. Otherwise, a lot of modification job 
are needed.

I noticed in this tread, you have asked a question about dtb, and Adam 
give a answer.
Did you get success?


On 08/08/2014 01:20 PM, Martin Schröder wrote:
> Hi Yunchuan,
> Am 08.08.2014 um 10:49 schrieb Yunchuan Geng:
>> Hi, L4hackers,
>> I am implementing I2C drivers from native linux to L4Linux. I am using
>> Freescale iMX6Q SD board. Kernel version 3.14
>> in ./drivers/i2c/busses/i2c-imx.c, function i2c_imx_probe(),
>> devm_clk_get() is called. And fails at here. I understand that clock are
>> initialized from function "__init imx6q_clocks_init()".
>> I managed to compile and call the imx6q_clocks_init() function from
>> L4Linux, but encountered many problem.
>> The question is, Is it necessary to initialize clocks in L4Linux and 
>> how?
> I had the same problem with clocking of the network driver in 
> fec_main.c. My approach is to do the clock setup outside of l4linux, 
> preferably let the bootloader (U-Boot) do this for me. So when the 
> driver is probed all clock setup can be skipped in the driver.
> Martin
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