From: Eero Nurkkala <ext-eero.nurkkala@xxxxxxxxx>
The prescalers for 100 kHz and 400 kHz mode
are wrong. The internal clock is the fclock
divided by the prescaler. The PSC is an 8 bit
field in omap3430. 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 <ext-eero.nurkkala@xxxxxxxxx>
---
drivers/i2c/busses/i2c-omap.c | 21 ++++++++++++++++++---
1 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index e708ebd..a42003a 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -288,7 +288,17 @@ 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 (cpu_is_omap34xx()) {
+ if (dev->speed > 400)
+ internal_clk = 19200;
+ else if (dev->speed > 100)
+ internal_clk = 9600;
+ else
+ internal_clk = 4000;
+ } else {
+ internal_clk = 19200;
+ }
+
fclk_rate = clk_get_rate(dev->fclk) / 1000;
/* Compute prescaler divisor */
@@ -306,8 +316,13 @@ 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;
+ if (cpu_is_omap34xx()) {
+ fsscll = internal_clk / (dev->speed * 2) - 7;
+ fssclh = internal_clk / (dev->speed * 2) - 5;
+ } else {
+ fsscll = internal_clk / (dev->speed * 2) - 6;
+ fssclh = internal_clk / (dev->speed * 2) - 6;
+ }
}
scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
--
1.6.0
--
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