clk: at91: add slow clks driver

AT91 slow clk is a clk multiplexer.

In some SoCs (sam9x5, sama5, sam9g45 families) this multiplexer can
choose among 2 sources: an internal RC oscillator circuit and an oscillator
using an external crystal.

In other Socs (sam9260 family) the multiplexer source is hardcoded with
the OSCSEL signal.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c
new file mode 100644
index 0000000..1184d76
--- /dev/null
+++ b/drivers/clk/at91/sckc.c
@@ -0,0 +1,57 @@
+/*
+ * drivers/clk/at91/sckc.c
+ *
+ *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#include "sckc.h"
+
+static const struct of_device_id sckc_clk_ids[] __initconst = {
+	/* Slow clock */
+	{
+		.compatible = "atmel,at91sam9x5-clk-slow-osc",
+		.data = of_at91sam9x5_clk_slow_osc_setup,
+	},
+	{
+		.compatible = "atmel,at91sam9x5-clk-slow-rc-osc",
+		.data = of_at91sam9x5_clk_slow_rc_osc_setup,
+	},
+	{
+		.compatible = "atmel,at91sam9x5-clk-slow",
+		.data = of_at91sam9x5_clk_slow_setup,
+	},
+	{ /*sentinel*/ }
+};
+
+static void __init of_at91sam9x5_sckc_setup(struct device_node *np)
+{
+	struct device_node *childnp;
+	void (*clk_setup)(struct device_node *, void __iomem *);
+	const struct of_device_id *clk_id;
+	void __iomem *regbase = of_iomap(np, 0);
+
+	if (!regbase)
+		return;
+
+	for_each_child_of_node(np, childnp) {
+		clk_id = of_match_node(sckc_clk_ids, childnp);
+		if (!clk_id)
+			continue;
+		clk_setup = clk_id->data;
+		clk_setup(childnp, regbase);
+	}
+}
+CLK_OF_DECLARE(at91sam9x5_clk_sckc, "atmel,at91sam9x5-sckc",
+	       of_at91sam9x5_sckc_setup);