dpll: zl3073x: Read DPLL types and pin properties from system firmware

Add support for reading of DPLL types and optional pin properties from
the system firmware (DT, ACPI...).

The DPLL types are stored in property 'dpll-types' as string array and
possible values 'pps' and 'eec' are mapped to DPLL enums DPLL_TYPE_PPS
and DPLL_TYPE_EEC.

The pin properties are stored under 'input-pins' and 'output-pins'
sub-nodes and the following ones are supported:

* reg
    integer that specifies pin index
* label
    string that is used by driver as board label
* connection-type
    string that indicates pin connection type
* supported-frequencies-hz
    array of u64 values what frequencies are supported / allowed for
    given pin with respect to hardware wiring

Do not blindly trust system firmware and filter out frequencies that
cannot be configured/represented in device (input frequencies have to
be factorized by one of the base frequencies and output frequencies have
to divide configured synthesizer frequency).

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20250704182202.1641943-8-ivecera@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: ivecera

drivers/dpll/zl3073x/Makefile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_ZL3073X)		+= zl3073x.o
-zl3073x-objs			:= core.o devlink.o
+zl3073x-objs			:= core.o devlink.o prop.o
 
 obj-$(CONFIG_ZL3073X_I2C)	+= zl3073x_i2c.o
 zl3073x_i2c-objs		:= i2c.o

drivers/dpll/zl3073x/core.c

@@ -128,6 +128,47 @@ const struct regmap_config zl3073x_regmap_config = {
 };
 EXPORT_SYMBOL_NS_GPL(zl3073x_regmap_config, "ZL3073X");
 
+/**
+ * zl3073x_ref_freq_factorize - factorize given frequency
+ * @freq: input frequency
+ * @base: base frequency
+ * @mult: multiplier
+ *
+ * Checks if the given frequency can be factorized using one of the
+ * supported base frequencies. If so the base frequency and multiplier
+ * are stored into appropriate parameters if they are not NULL.
+ *
+ * Return: 0 on success, -EINVAL if the frequency cannot be factorized
+ */
+int
+zl3073x_ref_freq_factorize(u32 freq, u16 *base, u16 *mult)
+{
+	static const u16 base_freqs[] = {
+		1, 2, 4, 5, 8, 10, 16, 20, 25, 32, 40, 50, 64, 80, 100, 125,
+		128, 160, 200, 250, 256, 320, 400, 500, 625, 640, 800, 1000,
+		1250, 1280, 1600, 2000, 2500, 3125, 3200, 4000, 5000, 6250,
+		6400, 8000, 10000, 12500, 15625, 16000, 20000, 25000, 31250,
+		32000, 40000, 50000, 62500,
+	};
+	u32 div;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(base_freqs); i++) {
+		div = freq / base_freqs[i];
+
+		if (div <= U16_MAX && (freq % base_freqs[i]) == 0) {
+			if (base)
+				*base = base_freqs[i];
+			if (mult)
+				*mult = div;
+
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
 static bool
 zl3073x_check_reg(struct zl3073x_dev *zldev, unsigned int reg, size_t size)
 {

drivers/dpll/zl3073x/core.h

@@ -14,6 +14,7 @@ struct regmap;
 /*
  * Hardware limits for ZL3073x chip family
  */
+#define ZL3073X_MAX_CHANNELS	5
 #define ZL3073X_NUM_REFS	10
 #define ZL3073X_NUM_OUTS	10
 #define ZL3073X_NUM_SYNTHS	5
@@ -107,6 +108,12 @@ int zl3073x_write_u16(struct zl3073x_dev *zldev, unsigned int reg, u16 val);
 int zl3073x_write_u32(struct zl3073x_dev *zldev, unsigned int reg, u32 val);
 int zl3073x_write_u48(struct zl3073x_dev *zldev, unsigned int reg, u64 val);
 
+/*****************
+ * Misc operations
+ *****************/
+
+int zl3073x_ref_freq_factorize(u32 freq, u16 *base, u16 *mult);
+
 static inline bool
 zl3073x_is_n_pin(u8 id)
 {