On Fri, Jun 21, 2013 at 11:14:07AM -0700, Simon Pearson wrote: > From: Simon Pearson <spear...@acumalabs.com> > > Kernel 3.8.4. By defining both the set and clear registers, > the speed of the gpio isimproved. gpio-generic.c, selects the > bgpio_set_with_clear() which isfaster than the current > bgpio_set_set(). This has performance implications for all > bitbang drivers (i2c, spi, etc). Slow SPI as compared to > 2.6.35.33 improved by a factor of 10 (80kHz CLK to 800kHz CLK). > > Signed-off-by: Simon Pearson <spear...@acumalabs.com>
The latest mainline kernel already has the improvement made by commit 90dae4e (gpio: mxs: Use set and clear capabilities of the gpio controller). Shawn > > --- > --- a/drivers/gpio/gpio-mxs.c.orig 2013-03-20 13:11:19.000000000 -0700 > +++ b/drivers/gpio/gpio-mxs.c 2013-06-21 10:02:33.000000000 -0700 > @@ -292,7 +292,8 @@ static int mxs_gpio_probe(struct platfor > > err = bgpio_init(&port->bgc, &pdev->dev, 4, > port->base + PINCTRL_DIN(port), > - port->base + PINCTRL_DOUT(port), NULL, > + port->base + PINCTRL_DOUT(port) + MXS_SET, > + port->base + PINCTRL_DOUT(port) + MXS_CLR, > port->base + PINCTRL_DOE(port), NULL, 0); > if (err) > goto out_irqdesc_free; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
