On Fri, Dec 11, 2015 at 10:24:09AM +0800, Gao Pan wrote:
> In our former i2c driver, i2c clk is enabled and disabled in
> xfer function, which contributes to power saving. However,
> the clk enable process brings a busy wait delay until the core
> is stable. As a result, the performance is sacrificed.
> 
> To weigh the power consumption and i2c bus performance, runtime
> pm is the good solution for it. The clk is enabled when a i2c
> transfer starts, and disabled after a specifically defined delay.
> 
> If CONFIG_PM is disabled the net result of this patch is that the
> clock is never disabled.
> 
> Without the patch the test case (many eeprom reads) executes with approx:
> real 1m7.735s
> user 0m0.488s
> sys 0m20.040s
> 
> With the patch the same test case (many eeprom reads) executes with approx:
> real 0m54.241s
> user 0m0.440s
> sys 0m5.920s
> 
> Signed-off-by: Fugang Duan <b38...@freescale.com>
> Signed-off-by: Gao Pan <b54...@freescale.com>
> Acked-by: Uwe Kleine-K├Ânig <u.kleine-koe...@pengutronix.de>

Applied to for-next, thanks! Also much thanks to Uwe and Heiner for the
reviews of all these versions!

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