Re: [PATCH v2 5/6] ARM: AM43xx: clk: Change the cpts ref clock source to dpll_core_m5 clk

From: Tero Kristo
Date: Mon May 05 2014 - 08:23:17 EST


On 05/02/2014 09:32 AM, George Cherian wrote:
cpsw_cpts_rft_clk has got the choice of 3 clocksources
-dpll_core_m4_ck
-dpll_core_m5_ck
-dpll_disp_m2_ck

By default dpll_core_m4_ck is selected, witn this as clock
source the CPTS doesnot work properly. It gives clockcheck errors
while running PTP.

clockcheck: clock jumped backward or running slower than expected!

By selecting dpll_core_m5_ck as the clocksource fixes this issue.
In AM335x dpll_core_m5_ck is the default clocksource.

Signed-off-by: George Cherian <george.cherian@xxxxxx>

Acked-by: Tero Kristo <t-kristo@xxxxxx>

---
drivers/clk/ti/clk-43xx.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/drivers/clk/ti/clk-43xx.c b/drivers/clk/ti/clk-43xx.c
index 67c8de5..b4877e0 100644
--- a/drivers/clk/ti/clk-43xx.c
+++ b/drivers/clk/ti/clk-43xx.c
@@ -110,9 +110,25 @@ static struct ti_dt_clk am43xx_clks[] = {

int __init am43xx_dt_clk_init(void)
{
+ struct clk *clk1, *clk2;
+
ti_dt_clocks_register(am43xx_clks);

omap2_clk_disable_autoidle_all();

+ /*
+ * cpsw_cpts_rft_clk has got the choice of 3 clocksources
+ * dpll_core_m4_ck, dpll_core_m5_ck and dpll_disp_m2_ck.
+ * By default dpll_core_m4_ck is selected, witn this as clock
+ * source the CPTS doesnot work properly. It gives clockcheck errors
+ * while running PTP.
+ * clockcheck: clock jumped backward or running slower than expected!
+ * By selecting dpll_core_m5_ck as the clocksource fixes this issue.
+ * In AM335x dpll_core_m5_ck is the default clocksource.
+ */
+ clk1 = clk_get_sys(NULL, "cpsw_cpts_rft_clk");
+ clk2 = clk_get_sys(NULL, "dpll_core_m5_ck");
+ clk_set_parent(clk1, clk2);
+
return 0;
}


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