clk: meson: add clk-input helper function

Add the clock input helper function. Several amlogic clock controllers
will now be registering bypass clock input. Instead of copying this
code in every of them, let's make an helper function for it

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
[narmstrong: fixed up to apply on Makefile and clkc.h]
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181204165819.21541-2-jbrunet@baylibre.com

drivers/clk/meson/Makefile

@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o vid-pll-div.o
+obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-input.o
 obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO)	+= clk-triphase.o sclk-div.o
 obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o
 obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o

drivers/clk/meson/clk-input.c

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Copyright (c) 2018 BayLibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include "clkc.h"
+
+static const struct clk_ops meson_clk_no_ops = {};
+
+struct clk_hw *meson_clk_hw_register_input(struct device *dev,
+					   const char *of_name,
+					   const char *clk_name,
+					   unsigned long flags)
+{
+	struct clk *parent_clk = devm_clk_get(dev, of_name);
+	struct clk_init_data init;
+	const char *parent_name;
+	struct clk_hw *hw;
+	int ret;
+
+	if (IS_ERR(parent_clk))
+		return (struct clk_hw *)parent_clk;
+
+	hw = devm_kzalloc(dev, sizeof(*hw), GFP_KERNEL);
+	if (!hw)
+		return ERR_PTR(-ENOMEM);
+
+	parent_name = __clk_get_name(parent_clk);
+	init.name = clk_name;
+	init.ops = &meson_clk_no_ops;
+	init.flags = flags;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	hw->init = &init;
+
+	ret = devm_clk_hw_register(dev, hw);
+
+	return ret ? ERR_PTR(ret) : hw;
+}
+EXPORT_SYMBOL_GPL(meson_clk_hw_register_input);

drivers/clk/meson/clkc.h

@@ -119,4 +119,9 @@ extern const struct clk_ops meson_clk_mpll_ops;
 extern const struct clk_ops meson_clk_phase_ops;
 extern const struct clk_ops meson_vid_pll_div_ro_ops;
 
+struct clk_hw *meson_clk_hw_register_input(struct device *dev,
+					   const char *of_name,
+					   const char *clk_name,
+					   unsigned long flags);
+
 #endif /* __CLKC_H */