On Thu, Oct 01, 2009 at 03:52:15PM +0800, Richard Zhao wrote:
> On Thu, Oct 1, 2009 at 3:26 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
> > On Thu, Oct 01, 2009 at 09:13:31AM +0800, Richard Zhao wrote:
> >> check cpu_is_mx1() when set disable_delay.
> >>
> >> Signed-off-by: Richard Zhao <linuxzsc@xxxxxxxxx>
> >>
> >> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> >> index 156cc95..c1e541c 100644
> >> --- a/drivers/i2c/busses/i2c-imx.c
> >> +++ b/drivers/i2c/busses/i2c-imx.c
> >> @@ -254,14 +254,16 @@ static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
> >> /* Write divider value to register */
> >> writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
> >>
> >> - /*
> >> - * There dummy delay is calculated.
> >> - * It should be about one I2C clock period long.
> >> - * This delay is used in I2C bus disable function
> >> - * to fix chip hardware bug.
> >> - */
> >> - i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0]
> >> - + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
> >> + if (cpu_is_mx1()) {
> >> + /*
> >> + * There dummy delay is calculated.
> >> + * It should be about one I2C clock period long.
> >> + * This delay is used in I2C bus disable function
> >> + * to fix chip hardware bug.
> >> + */
> >> + i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0]
> >> + + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
> >> + }
> >
> > I think you should put the udelay(i2c_imx->disable_delay) in
> > cpu_is_mx1() rather than the calculation.
> >
> > Sascha
> >
> >
> > --
> > Pengutronix e.K. | |
> > Industrial Linux Solutions | http://www.pengutronix.de/ |
> > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
> >
> Do you think udelay(0) wast any more time than if()?
if (cpu_is_mx1()) is optimized out by the compiler.
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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