* Eero Nurkkala <[email protected]> [081127 10:39]: > We scope-verified these scl and sch values for 100 and 400 kHz busses. > Now they're in the specs.
Pushing to l-o tree and adding to omap-fixes queue for mainline. Tony > On Wed, 2008-11-26 at 15:44 +0200, [email protected] wrote: > > From: Eero Nurkkala <[email protected]> > > > > The prescalers for 100 kHz and 400 kHz mode > > are wrong for omap 3430 and omap 2430. The > > internal clock is the fclock divided by the > > prescaler. The PSC is an 8 bit field in > > omap3430 and omap2430. Moreover, the scll and > > sclh values should be adjusted properly. > > Having the correct prescaler is important in > > the process of getting a finite i2c clock. In > > addition, the prescaler is used in the process > > of activating the correct noise filter and thus, > > lets more error resilient i2c communications. > > > > Signed-off-by: Eero Nurkkala <[email protected]> > > --- > > drivers/i2c/busses/i2c-omap.c | 12 +++++++++--- > > 1 files changed, 9 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > > index 630702c..c21af3f 100644 > > --- a/drivers/i2c/busses/i2c-omap.c > > +++ b/drivers/i2c/busses/i2c-omap.c > > @@ -337,7 +337,13 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) > > if (cpu_is_omap2430() || cpu_is_omap34xx()) { > > > > /* HSI2C controller internal clk rate should be 19.2 Mhz */ > > - internal_clk = 19200; > > + if (dev->speed > 400) > > + internal_clk = 19200; > > + else if (dev->speed > 100) > > + internal_clk = 9600; > > + else > > + internal_clk = 4000; > > + > > fclk_rate = clk_get_rate(dev->fclk) / 1000; > > > > /* Compute prescaler divisor */ > > @@ -355,8 +361,8 @@ static int omap_i2c_init(struct omap_i2c_dev *dev) > > hssclh = fclk_rate / (dev->speed * 2) - 6; > > } else { > > /* To handle F/S modes */ > > - fsscll = internal_clk / (dev->speed * 2) - 6; > > - fssclh = internal_clk / (dev->speed * 2) - 6; > > + fsscll = internal_clk / (dev->speed * 2) - 3; > > + fssclh = internal_clk / (dev->speed * 2) - 9; > > } > > scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll; > > sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh; > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
