clk: Port Linux common clock framework [CCF] for imx6q to U-boot (tag: v5.1.12)

This patch brings the files from Linux kernel (linux-stable/linux-5.1.y
SHA1: 5752b50477da)to provide clocks support as it is used on the Linux
kernel with Common Clock Framework [CCF] setup.

The directory structure has been preserved. The ported code only supports
reading information from PLL, MUX, Divider, etc and enabling/disabling
the clocks USDHCx/ECSPIx depending on used bus. Moreover, it is agnostic
to the alias numbering as the information about the clock is read from the
device tree.

One needs to pay attention to the comments indicating necessary for U-Boot's
driver model changes.

If needed, the code can be extended to support the "set" part of the clock
management.

Signed-off-by: Lukasz Majewski <lukma@denx.de>

1 files changed, 109 insertions, 0 deletions

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 6adf0a57913..e06487f07b4 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -9,6 +9,115 @@
 #ifndef __LINUX_CLK_PROVIDER_H
 #define __LINUX_CLK_PROVIDER_H
 
+static inline void clk_dm(ulong id, struct clk *clk)
+{
+	if (!IS_ERR(clk))
+		clk->id = id;
+}
+
+/*
+ * flags used across common struct clk.  these flags should only affect the
+ * top-level framework.  custom flags for dealing with hardware specifics
+ * belong in struct clk_foo
+ *
+ * Please update clk_flags[] in drivers/clk/clk.c when making changes here!
+ */
+#define CLK_SET_RATE_GATE	BIT(0) /* must be gated across rate change */
+#define CLK_SET_PARENT_GATE	BIT(1) /* must be gated across re-parent */
+#define CLK_SET_RATE_PARENT	BIT(2) /* propagate rate change up one level */
+#define CLK_IGNORE_UNUSED	BIT(3) /* do not gate even if unused */
+				/* unused */
+#define CLK_IS_BASIC		BIT(5) /* Basic clk, can't do a to_clk_foo() */
+#define CLK_GET_RATE_NOCACHE	BIT(6) /* do not use the cached clk rate */
+#define CLK_SET_RATE_NO_REPARENT BIT(7) /* don't re-parent on rate change */
+#define CLK_GET_ACCURACY_NOCACHE BIT(8) /* do not use the cached clk accuracy */
+#define CLK_RECALC_NEW_RATES	BIT(9) /* recalc rates after notifications */
+#define CLK_SET_RATE_UNGATE	BIT(10) /* clock needs to run to set rate */
+#define CLK_IS_CRITICAL		BIT(11) /* do not gate, ever */
+/* parents need enable during gate/ungate, set rate and re-parent */
+#define CLK_OPS_PARENT_ENABLE	BIT(12)
+/* duty cycle call may be forwarded to the parent clock */
+#define CLK_DUTY_CYCLE_PARENT	BIT(13)
+
+#define CLK_MUX_INDEX_ONE		BIT(0)
+#define CLK_MUX_INDEX_BIT		BIT(1)
+#define CLK_MUX_HIWORD_MASK		BIT(2)
+#define CLK_MUX_READ_ONLY		BIT(3) /* mux can't be changed */
+#define CLK_MUX_ROUND_CLOSEST		BIT(4)
+
+struct clk_mux {
+	struct clk	clk;
+	void __iomem	*reg;
+	u32		*table;
+	u32		mask;
+	u8		shift;
+	u8		flags;
+
+	/*
+	 * Fields from struct clk_init_data - this struct has been
+	 * omitted to avoid too deep level of CCF for bootloader
+	 */
+	const char	* const *parent_names;
+	u8		num_parents;
+};
+
+#define to_clk_mux(_clk) container_of(_clk, struct clk_mux, clk)
+
+struct clk_div_table {
+	unsigned int	val;
+	unsigned int	div;
+};
+
+struct clk_divider {
+	struct clk	clk;
+	void __iomem	*reg;
+	u8		shift;
+	u8		width;
+	u8		flags;
+	const struct clk_div_table	*table;
+};
+
+#define clk_div_mask(width)	((1 << (width)) - 1)
+#define to_clk_divider(_clk) container_of(_clk, struct clk_divider, clk)
+
+#define CLK_DIVIDER_ONE_BASED		BIT(0)
+#define CLK_DIVIDER_POWER_OF_TWO	BIT(1)
+#define CLK_DIVIDER_ALLOW_ZERO		BIT(2)
+#define CLK_DIVIDER_HIWORD_MASK		BIT(3)
+#define CLK_DIVIDER_ROUND_CLOSEST	BIT(4)
+#define CLK_DIVIDER_READ_ONLY		BIT(5)
+#define CLK_DIVIDER_MAX_AT_ZERO		BIT(6)
+
+struct clk_fixed_factor {
+	struct clk	clk;
+	unsigned int	mult;
+	unsigned int	div;
+};
+
+#define to_clk_fixed_factor(_clk) container_of(_clk, struct clk_fixed_factor,\
+					       clk)
+
+int clk_register(struct clk *clk, const char *drv_name, const char *name,
+		 const char *parent_name);
+
+struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div);
+
+struct clk *clk_register_divider(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_divider_flags);
+
+struct clk *clk_register_mux(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents,
+		unsigned long flags,
+		void __iomem *reg, u8 shift, u8 width,
+		u8 clk_mux_flags);
+
+const char *clk_hw_get_name(const struct clk *hw);
+ulong clk_generic_get_rate(struct clk *clk);
+
 static inline struct clk *dev_get_clk_ptr(struct udevice *dev)
 {
 	return (struct clk *)dev_get_uclass_priv(dev);