Re: [RFC] serial: mxc: get the clock frequency from the used clock for the device

...

• struct clk clk;
  

• if(!clk_get_by_name(dev, "ipg", &clk))
  

• 	rate = clk_get_rate(&clk);
  

• }
• /* as fallback we try to get the clk rate that way */
• if (rate == 0)

!rate || IS_ERR_VALUE(rate)

This looked so weird I had to actually look at clk_get_rate() in u-boot.

/** * clk_get_rate() - Get current clock rate. * @clk: A clock struct that was previously successfully requested by * clk_request/get_by_*(). * * Return: clock rate in Hz on success, 0 for invalid clock, or -ve error code * for other errors. */ ulong clk_get_rate(struct clk *clk);

How can an ulong return a negative error value? What if the clock speed happens to be the same as -errno?

-michael