1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/clk/clk-gate-shared.c b/drivers/clk/clk-gate-shared.c
new file mode 100644
index 0000000000..a95f940dd2
--- /dev/null
+++ b/drivers/clk/clk-gate-shared.c
@@ -0,0 +1,123 @@
+/*
+ * clk-gate-shared.c - generic barebox clock support. Based on Linux clk support
+ *
+ * Copyright (c) 2017 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <common.h>
+#include <io.h>
+#include <malloc.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+struct clk_gate_shared {
+	struct clk clk;
+	const char *parent;
+	const char *companion_gate;
+	struct clk *companion_clk;
+};
+
+#define to_clk_gate_shared(_clk) container_of(_clk, struct clk_gate_shared, clk)
+
+static struct clk *lookup_companion(struct clk_gate_shared *g)
+{
+	if (IS_ERR(g->companion_clk))
+		g->companion_clk = clk_lookup(g->companion_gate);
+
+	if (IS_ERR(g->companion_clk))
+		return NULL;
+
+	return g->companion_clk;
+}
+
+static int clk_gate_shared_enable(struct clk *clk)
+{
+	struct clk_gate_shared *g = to_clk_gate_shared(clk);
+
+	return clk_enable(lookup_companion(g));
+}
+
+static void clk_gate_shared_disable(struct clk *clk)
+{
+	struct clk_gate_shared *g = to_clk_gate_shared(clk);
+
+	clk_disable(lookup_companion(g));
+}
+
+static int clk_gate_shared_is_enabled(struct clk *clk)
+{
+	struct clk_gate_shared *g = to_clk_gate_shared(clk);
+
+	return clk_is_enabled(lookup_companion(g));
+}
+
+static struct clk_ops clk_gate_shared_ops = {
+	.set_rate = clk_parent_set_rate,
+	.round_rate = clk_parent_round_rate,
+	.enable = clk_gate_shared_enable,
+	.disable = clk_gate_shared_disable,
+	.is_enabled = clk_gate_shared_is_enabled,
+};
+
+struct clk *clk_gate_shared_alloc(const char *name, const char *parent, const char *companion,
+			   unsigned flags)
+{
+	struct clk_gate_shared *g = xzalloc(sizeof(*g));
+
+	g->parent = parent;
+	g->companion_gate = companion;
+	g->companion_clk = ERR_PTR(-EINVAL);
+	g->clk.ops = &clk_gate_shared_ops;
+	g->clk.name = name;
+	g->clk.flags = flags;
+	g->clk.parent_names = &g->parent;
+	g->clk.num_parents = 1;
+
+	return &g->clk;
+}
+
+void clk_gate_shared_free(struct clk *clk)
+{
+	struct clk_gate_shared *g = to_clk_gate_shared(clk);
+
+	free(g);
+}
+
+/*
+ * clk_gate_shared - register a gate controlled by another gate
+ * @name: The name of the new clock gate
+ * @parent: The parent name of the new clock
+ * companion: The hardware gate this clock is controlled by
+ * @flags: common CLK_* flags
+ *
+ * This gate clock is used when a single software control knob controls multiple
+ * gates in hardware. The first gate is then registered as the real hardware gate,
+ * the others are registered with this function. This gate has no hardware control
+ * itself, but only enables/disabled its companion hardware gate.
+ */
+struct clk *clk_gate_shared(const char *name, const char *parent, const char *companion,
+			    unsigned flags)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = clk_gate_shared_alloc(name , parent, companion, flags);
+
+	ret = clk_register(clk);
+	if (ret) {
+		clk_gate_shared_free(clk);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}