ARM: keystone2: PLL: Enable glitch free initialization sequence

Update the PLL initialization sequence to avoid glitches while
programming. User guide for the same is available at[1].

[1] http://www.ti.com/lit/ug/sprugv2h/sprugv2h.pdf

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/arch/arm/mach-keystone/clock.c b/arch/arm/mach-keystone/clock.c
index d880472..68f8980 100644 (file)
--- a/arch/arm/mach-keystone/clock.c
+++ b/arch/arm/mach-keystone/clock.c
@@ -163,15 +163,15 @@ void configure_secondary_pll(const struct pll_init_data *data)
 {
        int pllod = data->pll_od - 1;
 
+       /* Enable Glitch free bypass for ARM PLL */
+       if (cpu_is_k2hk() && data->pll == TETRIS_PLL)
+               clrbits_le32(KS2_MISC_CTRL, MISC_CTL1_ARM_PLL_EN);
+
        /* Enable Bypass mode */
        setbits_le32(keystone_pll_regs[data->pll].reg1, CFG_PLLCTL1_ENSAT_MASK);
        setbits_le32(keystone_pll_regs[data->pll].reg0,
                     CFG_PLLCTL0_BYPASS_MASK);
 
-       /* Enable Glitch free bypass for ARM PLL */
-       if (cpu_is_k2hk() && data->pll == TETRIS_PLL)
-               clrbits_le32(KS2_MISC_CTRL, MISC_CTL1_ARM_PLL_EN);
-
        configure_mult_div(data);
 
        /* Program Output Divider */
@@ -189,10 +189,6 @@ void configure_secondary_pll(const struct pll_init_data *data)
        if (data->pll == PASS_PLL && cpu_is_k2hk())
                pll_pa_clk_sel();
 
-       /* Select the Output of ARM PLL as input to ARM */
-       if (data->pll == TETRIS_PLL)
-               setbits_le32(KS2_MISC_CTRL, MISC_CTL1_ARM_PLL_EN);
-
        clrbits_le32(keystone_pll_regs[data->pll].reg1, CFG_PLLCTL1_RST_MASK);
        /* Wait for 500 * REFCLK cucles * (PLLD + 1) */
        sdelay(105000);
@@ -200,6 +196,10 @@ void configure_secondary_pll(const struct pll_init_data *data)
        /* Switch to PLL mode */
        clrbits_le32(keystone_pll_regs[data->pll].reg0,
                     CFG_PLLCTL0_BYPASS_MASK);
+
+       /* Select the Output of ARM PLL as input to ARM */
+       if (cpu_is_k2hk() && data->pll == TETRIS_PLL)
+               setbits_le32(KS2_MISC_CTRL, MISC_CTL1_ARM_PLL_EN);
 }
 
 void init_pll(const struct pll_init_data *data)