diff options
| author | Aaro Koskinen <aaro.koskinen@nokia.com> | 2009-05-27 17:54:46 +0300 |
|---|---|---|
| committer | Ben Dooks <ben-linux@fluff.org> | 2009-06-13 10:39:26 +0100 |
| commit | 84bf2c868f3ca996e5bbd3beb2ef502f457140f3 (patch) | |
| tree | cd35bf618469195161f2711b465dd63a50647054 | |
| parent | baf46b4e378d7950dff7ba30cfd50ff585987cb4 (diff) | |
| download | linux-84bf2c868f3ca996e5bbd3beb2ef502f457140f3.tar.gz linux-84bf2c868f3ca996e5bbd3beb2ef502f457140f3.tar.bz2 linux-84bf2c868f3ca996e5bbd3beb2ef502f457140f3.zip | |
i2c: OMAP3: Better noise suppression for fast/standard modes
Use longer noise filter period for fast and standard mode. Based on an
earlier patch by Eero Nurkkala.
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
| -rw-r--r-- | 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 a879e4bf5122..c73475dd0fba 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 */ |