* [PATCH 001/001] gpio-mxs: Select faster gpio-generic set methods
@ 2013-06-21 18:14 Simon Pearson
2013-06-24 6:59 ` Shawn Guo
0 siblings, 1 reply; 2+ messages in thread
From: Simon Pearson @ 2013-06-21 18:14 UTC (permalink / raw)
To: grant.likely, linus.walleij; +Cc: shawn.guo, linux-kernel
From: Simon Pearson <spearson@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 <spearson@acumalabs.com>
---
--- 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;
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH 001/001] gpio-mxs: Select faster gpio-generic set methods
2013-06-21 18:14 [PATCH 001/001] gpio-mxs: Select faster gpio-generic set methods Simon Pearson
@ 2013-06-24 6:59 ` Shawn Guo
0 siblings, 0 replies; 2+ messages in thread
From: Shawn Guo @ 2013-06-24 6:59 UTC (permalink / raw)
To: Simon Pearson; +Cc: grant.likely, linus.walleij, linux-kernel
On Fri, Jun 21, 2013 at 11:14:07AM -0700, Simon Pearson wrote:
> From: Simon Pearson <spearson@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 <spearson@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;
^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-06-21 18:14 [PATCH 001/001] gpio-mxs: Select faster gpio-generic set methods Simon Pearson
2013-06-24 6:59 ` Shawn Guo
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