Merge branches 'clockevents/4.4-fixes' and 'clockevents/4.5-fixes' of http://git.linaro.org/people/daniel.lezcano/linux into timers/urgent

Pull in fixes from Daniel Lezcano:

 - Fix the vt8500 timer leading to a system lock up when dealing with too
   small delta (Roman Volkov)

 - Select the CLKSRC_MMIO when the fsl_ftm_timer is enabled with COMPILE_TEST
   (Daniel Lezcano)

 - Prevent to compile timers using the 'iomem' API when the architecture has
   not HAS_IOMEM set (Richard Weinberger)

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;