[RFC 02/50] ARM: at91: add PMC main clock support using common clk framework.

[Boris BREZILLON <b.brezillon@overkiz.com>]

This is the at91 main oscillator clock implementation using common
clk framework.

If rate is not provided during clock registraction it is computed using
the slow clock (main clk parent in this case) rate and the MCFR register.


Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
---
 drivers/clk/at91/Makefile   |    5 ++
 drivers/clk/at91/clk-main.c |  106 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/clk/at91.h    |   10 ++++
 3 files changed, 121 insertions(+)

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
new file mode 100644
index 0000000..42c084e
--- /dev/null
+++ b/drivers/clk/at91/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for at91 specific clk
+#
+
+obj-y += clk-main.o
diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c
new file mode 100644
index 0000000..738fa39
--- /dev/null
+++ b/drivers/clk/at91/clk-main.c
@@ -0,0 +1,106 @@
+/*
+ * drivers/clk/at91/clk-main.c
+ *
+ *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
+ *
+ * This mainram 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/clk/at91.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+
+#define to_clk_main(hw) container_of(hw, struct clk_main, hw)
+struct clk_main {
+	struct clk_hw hw;
+	unsigned long rate;
+};
+
+static unsigned long clk_main_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	u32 tmp;
+	struct clk_main *clkmain = to_clk_main(hw);
+	if (clkmain->rate)
+		return clkmain->rate;
+	while ((tmp = at91_pmc_read(AT91_CKGR_MCFR)) & AT91_PMC_MAINRDY)
+		;
+	tmp &= AT91_PMC_MAINF;
+	clkmain->rate = (tmp * parent_rate) / 16;
+	return clkmain->rate;
+}
+
+static const struct clk_ops main_ops = {
+	.recalc_rate = clk_main_recalc_rate,
+};
+
+struct clk * __init
+at91_clk_register_main(const char *name,
+		       const char *parent_name,
+		       unsigned long rate)
+{
+	struct clk_main *clkmain;
+	struct clk *clk = NULL;
+	struct clk_init_data init;
+
+	if (!rate && !parent_name)
+		return ERR_PTR(-EINVAL);
+
+	clkmain = kzalloc(sizeof(*clkmain), GFP_KERNEL);
+	if (!clkmain)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &main_ops;
+	init.parent_names = parent_name ? &parent_name : NULL;
+	init.num_parents = parent_name ? 1 : 0;
+	init.flags = parent_name ? 0 : CLK_IS_ROOT;
+
+	clkmain->hw.init = &init;
+	clkmain->rate = rate;
+
+	clk = clk_register(NULL, &clkmain->hw);
+
+	if (IS_ERR(clk))
+		kfree(clkmain);
+
+	return clk;
+}
+
+
+
+#if defined(CONFIG_OF)
+static void __init
+of_at91_clk_main_setup(struct device_node *np)
+{
+	struct clk *clk;
+	const char *parent_name;
+	const char *name = np->name;
+	u32 rate = 0;
+
+	parent_name = of_clk_get_parent_name(np, 0);
+	of_property_read_string(np, "clock-output-names", &name);
+	of_property_read_u32(np, "clock-frequency", &rate);
+
+	clk = at91_clk_register_main(name, parent_name, rate);
+
+	if (!IS_ERR(clk))
+		return;
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static void __init of_at91rm9200_clk_main_setup(struct device_node *np)
+{
+	of_at91_clk_main_setup(np);
+}
+CLK_OF_DECLARE(at91rm9200_clk_main, "atmel,at91rm9200-clk-main",
+	       of_at91rm9200_clk_main_setup);
+#endif
diff --git a/include/linux/clk/at91.h b/include/linux/clk/at91.h
index 58b1eba..c0801e7 100644
--- a/include/linux/clk/at91.h
+++ b/include/linux/clk/at91.h
@@ -16,6 +16,8 @@
 #ifndef AT91_PMC_H
 #define AT91_PMC_H
 
+#include <linux/clk-provider.h>
+
 #ifndef __ASSEMBLY__
 extern void __iomem *at91_pmc_base;
 
@@ -184,4 +186,12 @@ extern void __iomem *at91_pmc_base;
 #define			AT91_PMC_PCR_DIV8	0x8			/* Peripheral clock is MCK/8 */
 #define		AT91_PMC_PCR_EN		(0x1  <<  28)		/* Enable */
 
+
+
+
+struct clk * __init
+at91_clk_register_main(const char *name,
+		       const char *parent_name,
+		       unsigned long rate);
+
 #endif
-- 
1.7.9.5