RFC: Could cpm2_clk_setup and cpm2_set_pin be exported ?

[Laurent Pinchart <laurentp@cse-semaphore.com>]

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Hi everybody,

I'm facing a situation where I need to call cpm2_clk_setup and cpm2_set_pin from a device driver compiled as a module. Before submitting a patch to export both functions, I'd like to make sure there isn't a cleaner way to implement the desired functionality without calling functions that are supposed to be used by board setup code.

The hardware is an Infineon SHDSL chip connected directly to 3 SCC ports of an MPC8248. The SHDSL ports roles can be set at runtime to Central Office or Remote Terminal (thing about a kind of master/slave configuration). SCC clock routing needs to configured at runtime to accommodate the ports roles (in one of the roles the SCC uses a baud rate generator, while in the other it receives the clock from the chip). Clocks are described in the device tree, so the driver does not hardcode clock values, but I need to call cpm2_clk_setup at runtime. Should this be done through board-supplied callbacks passed to the driver in a platform data structure (in which case I can't declare the device in the device tree as I'm doing now) or would it be acceptable to export cpm2_clk_setup ?

cpm2_set_pin is used for a similar purpose, as I have to setup BRG/CLK pins in input or output mode depending on the clock configuration. Additionally, cpm2_set_pin is also used to configure all inputs as outputs when the driver detects that the optional SDHSL module is not plugged in. Would it be safe to leave those pins as floating inputs, or could that potentially damage the MPC8248 ?

Thanks for your help.

Best regards,

-- 
Laurent Pinchart
CSE Semaphore Belgium

Chaussee de Bruxelles, 732A
B-1410 Waterloo
Belgium

T +32 (2) 387 42 59
F +32 (2) 387 42 75

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