diff options
| author | David S. Miller <[email protected]> | 2015-12-31 18:20:10 -0500 |
|---|---|---|
| committer | David S. Miller <[email protected]> | 2015-12-31 18:20:10 -0500 |
| commit | c07f30ad68053181b3e8a0e65b0630e12e844f91 (patch) | |
| tree | 8758968aabc844c435ff2a5d7d02c835fccd02a3 /drivers/i2c/busses/i2c-davinci.c | |
| parent | 7b22a7788b0263f42f7232c5c05c503424ffa0ba (diff) | |
| parent | 9c982e86dbdbaa3fb248dfc776dddda32cbc8927 (diff) | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'drivers/i2c/busses/i2c-davinci.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-davinci.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index c5628a42170a..a8bdcb5292f5 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -202,8 +202,15 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev) * d is always 6 on Keystone I2C controller */ - /* get minimum of 7 MHz clock, but max of 12 MHz */ - psc = (input_clock / 7000000) - 1; + /* + * Both Davinci and current Keystone User Guides recommend a value + * between 7MHz and 12MHz. In reality 7MHz module clock doesn't + * always produce enough margin between SDA and SCL transitions. + * Measurements show that the higher the module clock is, the + * bigger is the margin, providing more reliable communication. + * So we better target for 12MHz. + */ + psc = (input_clock / 12000000) - 1; if ((input_clock / (psc + 1)) > 12000000) psc++; /* better to run under spec than over */ d = (psc >= 2) ? 5 : 7 - psc; |