Commit ac07fb4d authored by Sonic Zhang's avatar Sonic Zhang Committed by Ben Dooks

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: default avatarSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent c9f937e4
......@@ -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);
......
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