From: Simon Pearson <[email protected]> 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 <[email protected]> --- --- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
