From: Sonic Zhang Date: Mon, 21 Dec 2009 14:28:30 +0000 (-0500) Subject: i2c-bfin-twi: fix CLKDIV calculation X-Git-Tag: firefly_0821_release~9833^2~3533^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ac07fb4dc1908d300f50fa711982c9d750eb59f7;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: Mike Frysinger Signed-off-by: Ben Dooks --- diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index b309ac2c3d5c..fe3fb567317d 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);