[PATCH v2 01/20] ARM: k3: Add function to enable 32k crystal

[Sascha Hauer]

The external 32k crystal is optional and by default LFOSC0 is sourced
by a RC oscillator. This adds a function to be called by board code
when the 32k crystal is present and shall be used to source LFOSC0
from the crystal.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 arch/arm/mach-k3/common.c | 20 ++++++++++++++++++++
 include/mach/k3/common.h  |  1 +
 2 files changed, 21 insertions(+)

diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
index 3922a0ff19..c779e873c9 100644
--- a/arch/arm/mach-k3/common.c
+++ b/arch/arm/mach-k3/common.c
@@ -170,6 +170,26 @@ static void of_delete_node_path(struct device_node *root, const char *path)
 	of_delete_node(np);
 }
 
+#define MCU_CTRL_MMR0_BASE			0x04500000
+#define MCU_CTRL_LFXOSC_CTRL			(MCU_CTRL_MMR0_BASE + 0x8038)
+#define MCU_CTRL_LFXOSC_32K_DISABLE_VAL		BIT(7)
+#define MCU_CTRL_DEVICE_CLKOUT_LFOSC_SELECT_VAL	(0x3)
+#define MCU_CTRL_DEVICE_CLKOUT_32K_CTRL		(MCU_CTRL_MMR0_BASE + 0x8058)
+
+void am625_enable_32k_crystal(void)
+{
+	u32 val;
+
+	/* Enable 32k crystal */
+	val = readl(MCU_CTRL_LFXOSC_CTRL);
+	val &= ~(MCU_CTRL_LFXOSC_32K_DISABLE_VAL);
+	writel(val, MCU_CTRL_LFXOSC_CTRL);
+
+	/* select 32k clock from LFOSC0 */
+	writel(MCU_CTRL_DEVICE_CLKOUT_LFOSC_SELECT_VAL,
+	       MCU_CTRL_DEVICE_CLKOUT_32K_CTRL);
+}
+
 #define CTRLMMR_WKUP_JTAG_DEVICE_ID	(AM625_WKUP_CTRL_MMR0_BASE + 0x18)
 
 #define JTAG_DEV_CORE_NR		GENMASK(21, 19)
diff --git a/include/mach/k3/common.h b/include/mach/k3/common.h
index d7ceea51d7..3377dc8895 100644
--- a/include/mach/k3/common.h
+++ b/include/mach/k3/common.h
@@ -6,5 +6,6 @@
 void am625_get_bootsource(enum bootsource *src, int *instance);
 u64 am625_sdram_size(void);
 void am625_register_dram(void);
+void am625_enable_32k_crystal(void);
 
 #endif /* __MACH_K3_COMMON_H */

-- 
2.39.5