[coreboot-gerrit] New patch to review for coreboot: 1f34b77 rk3288: guarantee i2c low period more than 1.3us

[Aaron Durbin]

Aaron Durbin ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/9259

-gerrit

commit 1f34b776d66704ad5eaf1cda327111da243d220b
Author: huang lin 
Date:   Fri Oct 10 23:26:21 2014 -0700

rk3288: guarantee i2c low period more than 1.3us

change i2c clock low period and high perid propoton to 7:3
    guarantee the low period more than 1.3us

BUG=None
    TEST=Boot on veyron_pinky rev2,check the i2c clock frequency

Original-Change-Id: I235e9e3ff54ab3b9cabad36bab58a8409f7005a0
    Original-Signed-off-by: huang lin 
    Original-Reviewed-on: https://chromium-review.googlesource.com/223002
    Original-Reviewed-by: Julius Werner

(cherry picked from commit 57a5d90d394086483e0dcdd6279678658d07d842)
    Signed-off-by: Aaron Durbin

Change-Id: I6b0c9dfa540354f6463ed90c9f3f9503a4d5749e
---
 src/soc/rockchip/rk3288/i2c.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/soc/rockchip/rk3288/i2c.c b/src/soc/rockchip/rk3288/i2c.c
index 142ec4a..eb480a7 100644
--- a/src/soc/rockchip/rk3288/i2c.c
+++ b/src/soc/rockchip/rk3288/i2c.c
@@ -284,7 +284,7 @@ void i2c_init(unsigned int bus, unsigned int hz)
    unsigned int clk_div;
    unsigned int divl;
    unsigned int divh;
-	unsigned int i2c_src_clk;
+	unsigned int i2c_src_clk = 0;
    struct rk3288_i2c_regs *regs = i2c_bus[bus];

/*i2c0,i2c2 src clk from pd_bus_pclk
@@ -308,9 +308,9 @@ void i2c_init(unsigned int bus, unsigned int hz)
    /*SCL Divisor = 8*(CLKDIVL + 1 + CLKDIVH + 1)
      SCL = PCLK/ SCLK Divisor
    */
-	clk_div = div_round_up(i2c_src_clk, hz * 8) - 2;
-	divh = clk_div / 2;
-	divl = ALIGN_UP(clk_div, 2) / 2;
+	clk_div = div_round_up(i2c_src_clk, hz * 8);
+	divh = clk_div * 3 / 7 - 1;
+	divl = clk_div - divh - 2;
    assert((divh < 65536) && (divl < 65536));
    writel((divh << 16) | (divl << 0), &regs->i2c_clkdiv);
 }