[PATCH v2 2/5] ARM: i.MX8MP: configure PLL3 as 600MHz

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

When running the i.MX8MP in nominal drive mode, a number of clocks are
validated only up to 600MHz: m7_core, audio_axi, vpu_bus, gpu_axi,
noc_io, vpu_g1.

Let's configure PLL3 as 600MHz to make it a suitable parent for these
clocks. The upstream Linux DTs don't yet use PLL3, but this aligns us
with U-Boot's boot-time configuration.

While at it, we also add a comment about how pll1 and pll2 are
configured.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
v1 -> v2:
  - no change
---
 arch/arm/mach-imx/imx8m.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-imx/imx8m.c b/arch/arm/mach-imx/imx8m.c
index d798c52c6a6e..211b4f782199 100644
--- a/arch/arm/mach-imx/imx8m.c
+++ b/arch/arm/mach-imx/imx8m.c
@@ -77,6 +77,13 @@ static void __imx8m_early_clock_init(int cpu_type)
 
 	imx8m_ccgr_clock_enable(IMX8M_CCM_CCGR_DDR1);
 
+	/*
+	 * The gate is not exported to clk tree, so configure them here.
+	 * According to ANAMIX SPEC
+	 * sys pll1 fixed at 800MHz
+	 * sys pll2 fixed at 1GHz
+	 * Here we only enable the outputs.
+	 */
 	val = readl(ana + IMX8MM_CCM_ANALOG_SYS_PLL1_GEN_CTRL);
 	val |= INTPLL_CLKE_MASK | INTPLL_DIV2_CLKE_MASK |
 		INTPLL_DIV3_CLKE_MASK | INTPLL_DIV4_CLKE_MASK |
@@ -100,7 +107,7 @@ static void __imx8m_early_clock_init(int cpu_type)
 				   IMX8M_CCM_TARGET_ROOTn_MUX(3));
 	imx8m_ccgr_clock_enable(IMX8M_CCM_CCGR_GIC);
 
-	if (cpu_type == IMX_CPU_IMX8MN)
+	if (cpu_type == IMX_CPU_IMX8MN || cpu_type == IMX_CPU_IMX8MP)
 		pll3_freq = 600000000UL;
 	else
 		pll3_freq = 750000000UL;
-- 
2.39.2