Thread (11 messages) flat view 11 messages, 5 authors, 2014-05-05

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

From: Tero Kristo <hidden>
Date: 2014-05-05 12:23:07
Also in: linux-devicetree, linux-omap, lkml, netdev

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 <redacted>
Acked-by: Tero Kristo <redacted>
quoted hunk ↗ jump to hunk
---
  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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