To calculate the dpll3 M2 clock stabilization delay dynamically and wait
time for L3 M2 clock stabilization are different for 3430 & 3630 and is
as follows:
3430: 4*REFCLK + 8*CLKOUTX2
3630: 2*SYS_CLK + 10*CLKOUTX2
REFCLK & CLKOUTX2 are derived from M, N, M2 and DPLL reference clock.
Incase of 3430 a 2usec and 3630 1usec buffer time is added for safety.
Signed-off-by: Pramod Gurav <pramod.gurav@xxxxxx>
Signed-off-by: Vishwanath Sripathy <vishwanath.bs@xxxxxx>
Signed-off-by: Ambresh K <ambresh@xxxxxx>
---
arch/arm/mach-omap2/clkt34xx_dpll3m2.c | 27 +++++++++++++++++++++------
1 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/arch/arm/mach-omap2/clkt34xx_dpll3m2.c b/arch/arm/mach-omap2/clkt34xx_dpll3m2.c
index 6ad18f2..af0807a 100644
--- a/arch/arm/mach-omap2/clkt34xx_dpll3m2.c
+++ b/arch/arm/mach-omap2/clkt34xx_dpll3m2.c
@@ -39,6 +39,12 @@
#define SHIFT_DPLL_M 16
#define SHIFT_DPLL_N 8
#define SHIFT_DPLL_M2 27
+
+/*
+ * While calculating M2 stabilization delay, especially the formula
+ * used for 3630 computes to zero. So to avoid calculation truncating to
+ * zero, SCALING_FACTOR is used appropriately.
+ */
#define SCALING_FACTOR 10
/*
@@ -107,12 +113,21 @@ int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate)
sys_clk = (1 << SCALING_FACTOR) / sys_clk_rate;
clkoutx2 = (sys_clk * (n + 1) * m2) / (2 * m);
- /* wait time for L3 clk stabilization = 4*REFCLK + 8*CLKOUTX2 */
- refclk = (n + 1) * sys_clk;
- switch_latency = (4 * refclk) + (8 * clkoutx2);
-
- /* Adding 2000 ns to sdrc clk stab */
- sdrc_clk_stab = switch_latency + 2000;
+ /*
+ * wait time for L3 clk stabilization
+ * for OMAP3430 = 4*REFCLK + 8*CLKOUTX2
+ * for OMAP3630 = 2*REFCLK + 8*CLKOUTX2
+ */
+ if (cpu_is_omap3630()) {
+ switch_latency = (2 * sys_clk) + (10 * clkoutx2);
+ /* Adding 1000 nano seconds to sdrc clk stab */
+ sdrc_clk_stab = switch_latency + 1000;
+ } else {
+ refclk = (n + 1) * sys_clk;
+ switch_latency = (4 * refclk) + (8 * clkoutx2);
+ /* Adding 2000 ns to sdrc clk stab */
+ sdrc_clk_stab = switch_latency + 2000;
+ }
/*
* Calculate the number of MPU cycles
--
1.6.0.4
--
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