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authorSonic Zhang <sonic.zhang@analog.com>2009-12-21 14:28:30 (GMT)
committerBen Dooks <ben-linux@fluff.org>2009-12-24 01:24:48 (GMT)
commitac07fb4dc1908d300f50fa711982c9d750eb59f7 (patch)
tree9a3e6149726b63a74d141bb4fe86b7fb3399435f /drivers/i2c
parentc9f937e4a3f4ebf9924ec21d80632e5eb61d949c (diff)
downloadlinux-ac07fb4dc1908d300f50fa711982c9d750eb59f7.tar.xz
i2c-bfin-twi: fix CLKDIV calculation
Calculation of the CLKDIV speed setting should be done using base 10 math rather than base 2. We also avoid exceeding the spec due to integer truncation and a 50% duty cycle. Signed-off-by: Sonic Zhang <sonic.zhang@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-bfin-twi.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index b309ac2..fe3fb56 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -693,13 +693,13 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
}
/* Set TWI internal clock as 10MHz */
- write_CONTROL(iface, ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
+ write_CONTROL(iface, ((get_sclk() / 1000 / 1000 + 5) / 10) & 0x7F);
/*
* We will not end up with a CLKDIV=0 because no one will specify
- * 20kHz SCL or less in Kconfig now. (5 * 1024 / 20 = 0x100)
+ * 20kHz SCL or less in Kconfig now. (5 * 1000 / 20 = 250)
*/
- clkhilow = 5 * 1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ;
+ clkhilow = ((10 * 1000 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ) + 1) / 2;
/* Set Twi interface clock as specified */
write_CLKDIV(iface, (clkhilow << 8) | clkhilow);