[PATCH 1/5] iio: at91: use adc_clk_khz to make the calculation not easy to large than u32.

[maxime.ripard@free-electrons.com (Maxime Ripard)]

Hi Josh,

On Sun, Jul 14, 2013 at 04:04:25PM +0800, Josh Wu wrote:
> for example, if adc_clk is 20Mhz and start-up time set as larger than 215us.
> then the calculation "st->startup_time * adc_clk_khz" will out of u32.
> 
> In this patch, it will use khz unit for adc_clk, that avoids above problem.
> 
> Signed-off-by: Josh Wu <josh.wu@atmel.com>

Maybe we can have a slightly better commit log here, like:

------8<-----------
iio: at91: Fix adc_clk overflow

The adc_clk variable is currently defined using a 32-bits unsigned
integer, which will overflow under some very valid range of operations.

Such overflow will occur if, for example, the parent clock is set to a
20MHz frequency and the ADC startup time is larger than 215ns.

To fix this, introduce an intermediate variable holding the clock rate
in kHz.

--------8<---------------

Or something like that.

For the patch itself, I'm happy about it. You can add my Acked-by.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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