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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-12-19 09:52:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-12-19 09:52:44 -0800 |
| commit | d7d3d84194e42a357a61a50219e5c2dd6b09bc42 (patch) | |
| tree | 3cb5adf54600f06df92ca48d3ae56cc20e85d3ec /drivers/i2c/busses/i2c-davinci.c | |
| parent | 632f8577d694efa4f2968be32c44e79f7e2ed2cd (diff) | |
| parent | b4cd08aa1f53c831e67dc5c6bc9f9acff27abcba (diff) | |
Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
"A set of 'usual' driver bugfixes for the I2C subsystem"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: rcar: disable runtime PM correctly in slave mode
i2c: designware: Keep pm_runtime_enable/_disable calls in sync
i2c: designware: fix IO timeout issue for AMD controller
i2c: imx: init bus recovery info before adding i2c adapter
i2c: do not use 0x in front of %pa
i2c: davinci: Increase module clock frequency
i2c: mv64xxx: The n clockdiv factor is 0 based on sunxi SoCs
i2c: rk3x: populate correct variable for sda_falling_time
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; |