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>

4 files changed, 371 insertions, 0 deletions

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 7a10bc9a23e7..ace7309c4369 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_ARCH_TEGRA)	+= tegra/
 obj-$(CONFIG_PLAT_SAMSUNG)      += samsung/
 obj-$(CONFIG_COMMON_CLK_XGENE)  += clk-xgene.o
 obj-$(CONFIG_COMMON_CLK_KEYSTONE)       += keystone/
+obj-$(CONFIG_COMMON_CLK_AT91)   += at91/
 
 obj-$(CONFIG_X86)               += x86/
 
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
new file mode 100644
index 000000000000..1d4fb214bbc4
--- /dev/null
+++ b/drivers/clk/at91/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for at91 specific clk
+#
+
+obj-y += pmc.o
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
new file mode 100644
index 000000000000..69c116a6ba4f
--- /dev/null
+++ b/drivers/clk/at91/pmc.c
@@ -0,0 +1,304 @@
+/*
+ *  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/clk/at91_pmc.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
+
+#include <asm/proc-fns.h>
+
+#include "pmc.h"
+
+void __iomem *at91_pmc_base;
+EXPORT_SYMBOL_GPL(at91_pmc_base);
+
+void at91sam9_idle(void)
+{
+        at91_pmc_write(AT91_PMC_SCDR, AT91_PMC_PCK);
+        cpu_do_idle();
+}
+
+int of_at91_get_clk_range(struct device_node *np, const char *propname,
+                          struct clk_range *range)
+{
+        u32 min, max;
+        int ret;
+
+        ret = of_property_read_u32_index(np, propname, 0, &min);
+        if (ret)
+                return ret;
+
+        ret = of_property_read_u32_index(np, propname, 1, &max);
+        if (ret)
+                return ret;
+
+        if (range) {
+                range->min = min;
+                range->max = max;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(of_at91_get_clk_range);
+
+static void pmc_irq_mask(struct irq_data *d)
+{
+        struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
+
+        pmc_write(pmc, AT91_PMC_IDR, 1 << d->hwirq);
+}
+
+static void pmc_irq_unmask(struct irq_data *d)
+{
+        struct at91_pmc *pmc = irq_data_get_irq_chip_data(d);
+
+        pmc_write(pmc, AT91_PMC_IER, 1 << d->hwirq);
+}
+
+static int pmc_irq_set_type(struct irq_data *d, unsigned type)
+{
+        if (type != IRQ_TYPE_LEVEL_HIGH) {
+                pr_warn("PMC: type not supported (support only IRQ_TYPE_LEVEL_HIGH type)\n");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static struct irq_chip pmc_irq = {
+        .name = "PMC",
+        .irq_disable = pmc_irq_mask,
+        .irq_mask = pmc_irq_mask,
+        .irq_unmask = pmc_irq_unmask,
+        .irq_set_type = pmc_irq_set_type,
+};
+
+static struct lock_class_key pmc_lock_class;
+
+static int pmc_irq_map(struct irq_domain *h, unsigned int virq,
+                       irq_hw_number_t hw)
+{
+        struct at91_pmc *pmc = h->host_data;
+
+        irq_set_lockdep_class(virq, &pmc_lock_class);
+
+        irq_set_chip_and_handler(virq, &pmc_irq,
+                                 handle_level_irq);
+        set_irq_flags(virq, IRQF_VALID);
+        irq_set_chip_data(virq, pmc);
+
+        return 0;
+}
+
+static int pmc_irq_domain_xlate(struct irq_domain *d,
+                                struct device_node *ctrlr,
+                                const u32 *intspec, unsigned int intsize,
+                                irq_hw_number_t *out_hwirq,
+                                unsigned int *out_type)
+{
+        struct at91_pmc *pmc = d->host_data;
+        const struct at91_pmc_caps *caps = pmc->caps;
+
+        if (WARN_ON(intsize < 1))
+                return -EINVAL;
+
+        *out_hwirq = intspec[0];
+
+        if (!(caps->available_irqs & (1 << *out_hwirq)))
+                return -EINVAL;
+
+        *out_type = IRQ_TYPE_LEVEL_HIGH;
+
+        return 0;
+}
+
+static struct irq_domain_ops pmc_irq_ops = {
+        .map    = pmc_irq_map,
+        .xlate  = pmc_irq_domain_xlate,
+};
+
+static irqreturn_t pmc_irq_handler(int irq, void *data)
+{
+        struct at91_pmc *pmc = (struct at91_pmc *)data;
+        unsigned long sr;
+        int n;
+
+        sr = pmc_read(pmc, AT91_PMC_SR) & pmc_read(pmc, AT91_PMC_IMR);
+        if (!sr)
+                return IRQ_NONE;
+
+        for_each_set_bit(n, &sr, BITS_PER_LONG)
+                generic_handle_irq(irq_find_mapping(pmc->irqdomain, n));
+
+        return IRQ_HANDLED;
+}
+
+static const struct at91_pmc_caps at91rm9200_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_LOCKB |
+                          AT91_PMC_MCKRDY | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY | AT91_PMC_PCK2RDY |
+                          AT91_PMC_PCK3RDY,
+};
+
+static const struct at91_pmc_caps at91sam9260_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_LOCKB |
+                          AT91_PMC_MCKRDY | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY,
+};
+
+static const struct at91_pmc_caps at91sam9g45_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_MCKRDY |
+                          AT91_PMC_LOCKU | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY,
+};
+
+static const struct at91_pmc_caps at91sam9n12_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_LOCKB |
+                          AT91_PMC_MCKRDY | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY | AT91_PMC_MOSCSELS |
+                          AT91_PMC_MOSCRCS | AT91_PMC_CFDEV,
+};
+
+static const struct at91_pmc_caps at91sam9x5_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_MCKRDY |
+                          AT91_PMC_LOCKU | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY | AT91_PMC_MOSCSELS |
+                          AT91_PMC_MOSCRCS | AT91_PMC_CFDEV,
+};
+
+static const struct at91_pmc_caps sama5d3_caps = {
+        .available_irqs = AT91_PMC_MOSCS | AT91_PMC_LOCKA | AT91_PMC_MCKRDY |
+                          AT91_PMC_LOCKU | AT91_PMC_PCK0RDY |
+                          AT91_PMC_PCK1RDY | AT91_PMC_PCK2RDY |
+                          AT91_PMC_MOSCSELS | AT91_PMC_MOSCRCS |
+                          AT91_PMC_CFDEV,
+};
+
+static struct at91_pmc *__init at91_pmc_init(struct device_node *np,
+                                             void __iomem *regbase, int virq,
+                                             const struct at91_pmc_caps *caps)
+{
+        struct at91_pmc *pmc;
+
+        if (!regbase || !virq ||  !caps)
+                return NULL;
+
+        at91_pmc_base = regbase;
+
+        pmc = kzalloc(sizeof(*pmc), GFP_KERNEL);
+        if (!pmc)
+                return NULL;
+
+        spin_lock_init(&pmc->lock);
+        pmc->regbase = regbase;
+        pmc->virq = virq;
+        pmc->caps = caps;
+
+        pmc->irqdomain = irq_domain_add_linear(np, 32, &pmc_irq_ops, pmc);
+
+        if (!pmc->irqdomain)
+                goto out_free_pmc;
+
+        pmc_write(pmc, AT91_PMC_IDR, 0xffffffff);
+        if (request_irq(pmc->virq, pmc_irq_handler, IRQF_SHARED, "pmc", pmc))
+                goto out_remove_irqdomain;
+
+        return pmc;
+
+out_remove_irqdomain:
+        irq_domain_remove(pmc->irqdomain);
+out_free_pmc:
+        kfree(pmc);
+
+        return NULL;
+}
+
+static const struct of_device_id pmc_clk_ids[] __initdata = {
+        { /*sentinel*/ }
+};
+
+static void __init of_at91_pmc_setup(struct device_node *np,
+                                     const struct at91_pmc_caps *caps)
+{
+        struct at91_pmc *pmc;
+        struct device_node *childnp;
+        void (*clk_setup)(struct device_node *, struct at91_pmc *);
+        const struct of_device_id *clk_id;
+        void __iomem *regbase = of_iomap(np, 0);
+        int virq;
+
+        if (!regbase)
+                return;
+
+        virq = irq_of_parse_and_map(np, 0);
+        if (!virq)
+                return;
+
+        pmc = at91_pmc_init(np, regbase, virq, caps);
+        if (!pmc)
+                return;
+        for_each_child_of_node(np, childnp) {
+                clk_id = of_match_node(pmc_clk_ids, childnp);
+                if (!clk_id)
+                        continue;
+                clk_setup = clk_id->data;
+                clk_setup(childnp, pmc);
+        }
+}
+
+static void __init of_at91rm9200_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &at91rm9200_caps);
+}
+CLK_OF_DECLARE(at91rm9200_clk_pmc, "atmel,at91rm9200-pmc",
+               of_at91rm9200_pmc_setup);
+
+static void __init of_at91sam9260_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &at91sam9260_caps);
+}
+CLK_OF_DECLARE(at91sam9260_clk_pmc, "atmel,at91sam9260-pmc",
+               of_at91sam9260_pmc_setup);
+
+static void __init of_at91sam9g45_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &at91sam9g45_caps);
+}
+CLK_OF_DECLARE(at91sam9g45_clk_pmc, "atmel,at91sam9g45-pmc",
+               of_at91sam9g45_pmc_setup);
+
+static void __init of_at91sam9n12_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &at91sam9n12_caps);
+}
+CLK_OF_DECLARE(at91sam9n12_clk_pmc, "atmel,at91sam9n12-pmc",
+               of_at91sam9n12_pmc_setup);
+
+static void __init of_at91sam9x5_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &at91sam9x5_caps);
+}
+CLK_OF_DECLARE(at91sam9x5_clk_pmc, "atmel,at91sam9x5-pmc",
+               of_at91sam9x5_pmc_setup);
+
+static void __init of_sama5d3_pmc_setup(struct device_node *np)
+{
+        of_at91_pmc_setup(np, &sama5d3_caps);
+}
+CLK_OF_DECLARE(sama5d3_clk_pmc, "atmel,sama5d3-pmc",
+               of_sama5d3_pmc_setup);
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_ */