From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 2/2] I2C: OMAP3: Better noise suppression for fast/standard modes Date: Tue, 2 Jun 2009 10:52:07 -0700 Message-ID: <20090602175206.GH27332@atomide.com> References: <1243436086-3623-1-git-send-email-aaro.koskinen@nokia.com> <1243436086-3623-2-git-send-email-aaro.koskinen@nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1243436086-3623-2-git-send-email-aaro.koskinen@nokia.com> Sender: linux-omap-owner@vger.kernel.org To: Ben Dooks , Aaro Koskinen Cc: linux-i2c@vger.kernel.org, linux-omap@vger.kernel.org List-Id: linux-i2c@vger.kernel.org * Aaro Koskinen [090527 07:55]: > Use longer noise filter period for fast and standard mode. Based on an > earlier patch by Eero Nurkkala. > > Signed-off-by: Aaro Koskinen Ben this should be queued too. Acked-by: Tony Lindgren > --- > drivers/i2c/busses/i2c-omap.c | 14 ++++++++++++-- > 1 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index 5d9880c..8c76cea 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -333,8 +333,18 @@ 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; > + /* > + * HSI2C controller internal clk rate should be 19.2 Mhz for > + * HS and for all modes on 2430. On 34xx we can use lower rate > + * to get longer filter period for better noise suppression. > + * The filter is iclk (fclk for HS) period. > + */ > + if (dev->speed > 400 || cpu_is_omap_2430()) > + 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 */ > -- > 1.5.4.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html