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i2c: Blackfin TWI: make sure we don't end up with a CLKDIV=0 

Make sure we don't end up with an invalid CLKDIV=0 in case someone
specifies 20kHz SCL or less (5 * 1024 / 20 = 0x100).

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
[ben-linux@fluff.org: shortened subject line]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Michael Hennerich 2009-05-18 08:14:41 -04:00 committed by Ben Dooks
parent f3ad116588
commit 9528d1c7a5
2 changed files with 9 additions and 4 deletions
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2
drivers/i2c/busses/Kconfig
View File

@ -298,7 +298,7 @@ config I2C_BLACKFIN_TWI
config I2C_BLACKFIN_TWI_CLK_KHZ
int "Blackfin TWI I2C clock (kHz)"
depends on I2C_BLACKFIN_TWI
range 10 400
range 21 400
default 50
help
The unit of the TWI clock is kHz.

11
drivers/i2c/busses/i2c-bfin-twi.c
View File

@ -614,6 +614,7 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
struct i2c_adapter *p_adap;
struct resource *res;
int rc;
unsigned int clkhilow;
iface = kzalloc(sizeof(struct bfin_twi_iface), GFP_KERNEL);
if (!iface) {
@ -675,10 +676,14 @@ 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);
/*
* 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)
*/
clkhilow = 5 * 1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ;
/* Set Twi interface clock as specified */
write_CLKDIV(iface, ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
<< 8) | ((5*1024 / CONFIG_I2C_BLACKFIN_TWI_CLK_KHZ)
& 0xFF));
write_CLKDIV(iface, (clkhilow << 8) | clkhilow);
/* Enable TWI */
write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);