clk: at91: add PMC base support

This patch adds at91 PMC (Power Management Controller) base support.

All at91 clocks managed by the PMC unit will use this framework.

This framework provides the following fonctionalities:
- define a new struct at91_pmc to hide PMC internals (lock, PMC memory
  mapping, irq domain, ...)
- read/write helper functions (pmc_read/write) to access PMC registers
- lock/unlock helper functions (pmc_lock/unlock) to lock/unlock access to
  pmc registers
- a new irq domain and its associated irq chip to request PMC specific
  interrupts (useful for clk prepare callbacks)

The PMC unit is declared as a dt clk provider (CLK_OF_DECLARE), and every
clk using this framework will declare a table of of_at91_clk_init_cb_t
and add it to the pmc_clk_ids table.

When the pmc dt clock setup function is called (by of_clk_init function),
it triggers the registration of every supported child clk (those matching
the definitions in pmc_clk_ids).

This patch copies at91_pmc_base (memory mapping) and at91sam9_idle
(function) from arch/arm/mach-at91/clock.c (which is not compiled if
COMMON_CLK_AT91 is enabled).

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

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
new file mode 100644
index 000000000000..d92b946cdc9e
--- /dev/null
+++ b/drivers/clk/at91/pmc.h
@@ -0,0 +1,61 @@
+/*
+ * drivers/clk/at91/pmc.h
+ *
+ *  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.
+ */
+
+#ifndef __PMC_H_
+#define __PMC_H_
+
+#include <linux/io.h>
+#include <linux/irqdomain.h>
+#include <linux/spinlock.h>
+
+struct clk_range {
+	unsigned long min;
+	unsigned long max;
+};
+
+#define CLK_RANGE(MIN, MAX) {.min = MIN, .max = MAX,}
+
+struct at91_pmc_caps {
+	u32 available_irqs;
+};
+
+struct at91_pmc {
+	void __iomem *regbase;
+	int virq;
+	spinlock_t lock;
+	const struct at91_pmc_caps *caps;
+	struct irq_domain *irqdomain;
+};
+
+static inline void pmc_lock(struct at91_pmc *pmc)
+{
+	spin_lock(&pmc->lock);
+}
+
+static inline void pmc_unlock(struct at91_pmc *pmc)
+{
+	spin_unlock(&pmc->lock);
+}
+
+static inline u32 pmc_read(struct at91_pmc *pmc, int offset)
+{
+	return readl(pmc->regbase + offset);
+}
+
+static inline void pmc_write(struct at91_pmc *pmc, int offset, u32 value)
+{
+	writel(value, pmc->regbase + offset);
+}
+
+int of_at91_get_clk_range(struct device_node *np, const char *propname,
+			  struct clk_range *range);
+
+#endif /* __PMC_H_ */