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@xxxxxxxxx>
---
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
--
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