clk: fixed-factor: add optional accuracy support

Fixed factor clock reports the parent clock accuracy. Add flags and acc
fields to `struct clk_fixed_factor` to support setting a fixed
accuracy. The default if no flag is set is not changed: use the parent
clock accuracy.

Signed-off-by: Théo Lebrun <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/clk-fixed-factor.c

···
 	return 0;
 }
 
+static unsigned long clk_factor_recalc_accuracy(struct clk_hw *hw,
+						unsigned long parent_accuracy)
+{
+	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
+
+	if (fix->flags & CLK_FIXED_FACTOR_FIXED_ACCURACY)
+		return fix->acc;
+
+	return parent_accuracy;
+}
+
 const struct clk_ops clk_fixed_factor_ops = {
 	.round_rate = clk_factor_round_rate,
 	.set_rate = clk_factor_set_rate,
 	.recalc_rate = clk_factor_recalc_rate,
+	.recalc_accuracy = clk_factor_recalc_accuracy,
 };
 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
 
···
 		const char *name, const char *parent_name,
 		const struct clk_hw *parent_hw, int index,
 		unsigned long flags, unsigned int mult, unsigned int div,
-		bool devm)
+		unsigned long acc, unsigned int fixflags, bool devm)
 {
 	struct clk_fixed_factor *fix;
 	struct clk_init_data init = { };
···
 	fix->mult = mult;
 	fix->div = div;
 	fix->hw.init = &init;
+	fix->acc = acc;
+	fix->flags = fixflags;
 
 	init.name = name;
 	init.ops = &clk_fixed_factor_ops;
···
 		unsigned int mult, unsigned int div)
 {
 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, NULL, index,
-					      flags, mult, div, true);
+					      flags, mult, div, 0, 0, true);
 }
 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_index);
 
···
 		unsigned long flags, unsigned int mult, unsigned int div)
 {
 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, parent_hw,
-					      -1, flags, mult, div, true);
+					      -1, flags, mult, div, 0, 0, true);
 }
 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
 
···
 {
 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL,
 					      parent_hw, -1, flags, mult, div,
-					      false);
+					      0, 0, false);
 }
 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
 
···
 		unsigned int mult, unsigned int div)
 {
 	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
-					      flags, mult, div, false);
+					      flags, mult, div, 0, 0, false);
 }
 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
 
···
 		unsigned int mult, unsigned int div)
 {
 	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
-			flags, mult, div, true);
+			flags, mult, div, 0, 0, true);
 }
 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
 
···
 	of_property_read_string(node, "clock-output-names", &clk_name);
 
 	hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, NULL, 0,
-					    0, mult, div, false);
+					    0, mult, div, 0, 0, false);
 	if (IS_ERR(hw)) {
 		/*
 		 * Clear OF_POPULATED flag so that clock registration can be

include/linux/clk-provider.h

···
  * @hw:		handle between common and hardware-specific interfaces
  * @mult:	multiplier
  * @div:	divider
+ * @acc:	fixed accuracy in ppb
+ * @flags:	behavior modifying flags
  *
  * Clock with a fixed multiplier and divider. The output frequency is the
  * parent clock rate divided by div and multiplied by mult.
- * Implements .recalc_rate, .set_rate and .round_rate
+ * Implements .recalc_rate, .set_rate, .round_rate and .recalc_accuracy
+ *
+ * Flags:
+ * * CLK_FIXED_FACTOR_FIXED_ACCURACY - Use the value in @acc instead of the
+ *                                     parent clk accuracy.
  */
 
 struct clk_fixed_factor {
 	struct clk_hw	hw;
 	unsigned int	mult;
 	unsigned int	div;
+	unsigned long	acc;
+	unsigned int	flags;
 };
+
+#define CLK_FIXED_FACTOR_FIXED_ACCURACY	BIT(0)
 
 #define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)