Hello, On Mon, Aug 31, 2015 at 03:32:33PM +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. > > 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 <B38611@xxxxxxxxxxxxx> > Signed-off-by: Gao Pan <b54642@xxxxxxxxxxxxx> > [wsa: fixed some indentation] > Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx> Hmm, why does this already have a S-o-b from Wolfram? Other than that I don't have any caveats to enter any more, but given that I don't have much clue about runtime pm this doesn't mean much. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
