[coreboot-gerrit] New patch to review for coreboot: rockchip/common: Loosen I2C frequency target requirements

[Patrick Georgi]

Patrick Georgi ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18007

-gerrit

commit 02e37466ed490610d43dab529c1d9c7182ba6437
Author: Julius Werner 
Date:   Fri Dec 16 16:03:57 2016 -0800

rockchip/common: Loosen I2C frequency target requirements

I've recently added an assertion to ensure that the effective I2C
    frequency on Rockchip SoCs is not too far off the 400KHz target due to
    divisor rounding errors. A 10KHz margin worked fine for RK3399, but it
    turns out that RK3288 actually only ever hit 387KHz since its I2C clocks
    are based off the already pretty low 75MHz PCLKs. While we could
    probably change the PCLKs to make this closer, that seems like a too
    intrusive change for something that has already worked just fine for
    years, so just loosen the restriction a little more instead.

BRANCH=None
    BUG=chromium:675043
    TEST=None

Change-Id: I7e96a1a75b38f8ad3971dd33046699cceb17b80d
    Signed-off-by: Julius Werner 
    Reviewed-on: https://chromium-review.googlesource.com/421095
    Reviewed-by: Randall Spangler 
---
 src/soc/rockchip/common/i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/soc/rockchip/common/i2c.c b/src/soc/rockchip/common/i2c.c
index a00d538..032efda 100644
--- a/src/soc/rockchip/common/i2c.c
+++ b/src/soc/rockchip/common/i2c.c
@@ -286,6 +286,6 @@ void i2c_init(unsigned int bus, unsigned int hz)
    i2c_clk = i2c_src_clk / (8 * (divl + 1 + divh + 1));
    printk(BIOS_DEBUG, "I2C bus %u: %uHz (divh = %u, divl = %u)\n",
           bus, i2c_clk, divh, divl);
-	assert((divh < 65536) && (divl < 65536) && hz - i2c_clk < 10*KHz);
+	assert((divh < 65536) && (divl < 65536) && hz - i2c_clk < 15*KHz);
    write32(&regs->i2c_clkdiv, (divh << 16) | (divl << 0));
 }