[v5,07/17] clk: at91: add PMC master clock

Commit Message

Boris BREZILLON Nov. 12, 2013, 10 p.m. UTC

This patch adds new at91 master clock implementation using common clk
framework.

The master clock layout describe the MCKR register layout.
There are 2 master clock layouts:
- at91rm9200
- at91sam9x5

Master clocks are given characteristics:
- min/max clock output rate

These characteristics are checked during rate change to avoid
over/underclocking.

These characteristics are described in atmel's SoC datasheet in
"Electrical Characteristics" paragraph.

Signed-off-by: Boris BREZILLON <[e-mail]>
Acked-by: Nicolas Ferre <[e-mail]>
---
 drivers/clk/at91/Makefile     |    2 +-
 drivers/clk/at91/clk-master.c |  272 +++++++++++++++++++++++++++++++++++++++++
 drivers/clk/at91/clk-pll.c    |   10 +-
 drivers/clk/at91/pmc.c        |    9 ++
 drivers/clk/at91/pmc.h        |    5 +
 5 files changed, 289 insertions(+), 9 deletions(-)
 create mode 100644 drivers/clk/at91/clk-master.c

Patch

diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 902bbf1..e28fb2b 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -3,4 +3,4 @@ 
 #
 
 obj-y += pmc.o
-obj-y += clk-main.o clk-pll.o clk-plldiv.o
+obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o
diff --git a/drivers/clk/at91/clk-master.c b/drivers/clk/at91/clk-master.c
new file mode 100644
index 0000000..65b81de
--- /dev/null
+++ b/drivers/clk/at91/clk-master.c
@@ -0,0 +1,272 @@ 
+/*
+ * drivers/clk/at91/clk-master.c
+ *
+ *  Copyright (C) 2013 Boris BREZILLON <[e-mail]>
+ *
+ * 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/of_irq.h>
+#include <linux/io.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include "pmc.h"
+
+#define MASTER_SOURCE_MAX	4
+
+#define MASTER_PRES_MASK	0x7
+#define MASTER_PRES_MAX		MASTER_PRES_MASK
+#define MASTER_DIV_SHIFT	8
+#define MASTER_DIV_MASK		0x3
+
+struct clk_master_characteristics {
+	struct clk_range output;
+	u32 divisors[4];
+	u8 have_div3_pres;
+};
+
+struct clk_master_layout {
+	u32 mask;
+	u8 pres_shift;
+};
+
+#define to_clk_master(hw) container_of(hw, struct clk_master, hw)
+
+struct clk_master {
+	struct clk_hw hw;
+	struct at91_pmc *pmc;
+	unsigned int irq;
+	wait_queue_head_t wait;
+	const struct clk_master_layout *layout;
+	const struct clk_master_characteristics *characteristics;
+};
+
+static irqreturn_t clk_master_irq_handler(int irq, void *dev_id)
+{
+	struct clk_master *master = (struct clk_master *)dev_id;
+
+	wake_up(&master->wait);
+	disable_irq_nosync(master->irq);
+
+	return IRQ_HANDLED;
+}
+static int clk_master_prepare(struct clk_hw *hw)
+{
+	struct clk_master *master = to_clk_master(hw);
+	struct at91_pmc *pmc = master->pmc;
+
+	while (!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY)) {
+		enable_irq(master->irq);
+		wait_event(master->wait,
+			   pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY);
+	}
+
+	return 0;
+}
+
+static int clk_master_is_prepared(struct clk_hw *hw)
+{
+	struct clk_master *master = to_clk_master(hw);
+
+	return !!(pmc_read(master->pmc, AT91_PMC_SR) & AT91_PMC_MCKRDY);
+}
+
+static unsigned long clk_master_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	u8 pres;
+	u8 div;
+	unsigned long rate = parent_rate;
+	struct clk_master *master = to_clk_master(hw);
+	struct at91_pmc *pmc = master->pmc;
+	const struct clk_master_layout *layout = master->layout;
+	const struct clk_master_characteristics *characteristics =
+						master->characteristics;
+	u32 tmp;
+
+	pmc_lock(pmc);
+	tmp = pmc_read(pmc, AT91_PMC_MCKR) & layout->mask;
+	pmc_unlock(pmc);
+
+	pres = (tmp >> layout->pres_shift) & MASTER_PRES_MASK;
+	div = (tmp >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK;
+
+	if (characteristics->have_div3_pres && pres == MASTER_PRES_MAX)
+		rate /= 3;
+	else
+		rate >>= pres;
+
+	rate /= characteristics->divisors[div];
+
+	if (rate < characteristics->output.min)
+		pr_warn("master clk is underclocked");
+	else if (rate > characteristics->output.max)
+		pr_warn("master clk is overclocked");
+
+	return rate;
+}
+
+static u8 clk_master_get_parent(struct clk_hw *hw)
+{
+	struct clk_master *master = to_clk_master(hw);
+	struct at91_pmc *pmc = master->pmc;
+
+	return pmc_read(pmc, AT91_PMC_MCKR) & AT91_PMC_CSS;
+}
+
+static const struct clk_ops master_ops = {
+	.prepare = clk_master_prepare,
+	.is_prepared = clk_master_is_prepared,
+	.recalc_rate = clk_master_recalc_rate,
+	.get_parent = clk_master_get_parent,
+};
+
+static struct clk * __init
+at91_clk_register_master(struct at91_pmc *pmc, unsigned int irq,
+		const char *name, int num_parents,
+		const char **parent_names,
+		const struct clk_master_layout *layout,
+		const struct clk_master_characteristics *characteristics)
+{
+	int ret;
+	struct clk_master *master;
+	struct clk *clk = NULL;
+	struct clk_init_data init;
+
+	if (!pmc || !irq || !name || !num_parents || !parent_names)
+		return ERR_PTR(-EINVAL);
+
+	master = kzalloc(sizeof(*master), GFP_KERNEL);
+	if (!master)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &master_ops;
+	init.parent_names = parent_names;
+	init.num_parents = num_parents;
+	init.flags = 0;
+
+	master->hw.init = &init;
+	master->layout = layout;
+	master->characteristics = characteristics;
+	master->pmc = pmc;
+	master->irq = irq;
+	init_waitqueue_head(&master->wait);
+	irq_set_status_flags(master->irq, IRQ_NOAUTOEN);
+	ret = request_irq(master->irq, clk_master_irq_handler,
+			  IRQF_TRIGGER_HIGH, "clk-master", master);
+	if (ret)
+		return ERR_PTR(ret);
+
+	clk = clk_register(NULL, &master->hw);
+	if (IS_ERR(clk))
+		kfree(master);
+
+	return clk;
+}
+
+
+static const struct clk_master_layout at91rm9200_master_layout = {
+	.mask = 0x31F,
+	.pres_shift = 2,
+};
+
+static const struct clk_master_layout at91sam9x5_master_layout = {
+	.mask = 0x373,
+	.pres_shift = 4,
+};
+
+
+static struct clk_master_characteristics * __init
+of_at91_clk_master_get_characteristics(struct device_node *np)
+{
+	struct clk_master_characteristics *characteristics;
+
+	characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL);
+	if (!characteristics)
+		return NULL;
+
+	if (of_at91_get_clk_range(np, "atmel,clk-output-range", &characteristics->output))
+		goto out_free_characteristics;
+
+	of_property_read_u32_array(np, "atmel,clk-divisors",
+				   characteristics->divisors, 4);
+
+	characteristics->have_div3_pres =
+		of_property_read_bool(np, "atmel,master-clk-have-div3-pres");
+
+	return characteristics;
+
+out_free_characteristics:
+	kfree(characteristics);
+	return NULL;
+}
+
+static void __init
+of_at91_clk_master_setup(struct device_node *np, struct at91_pmc *pmc,
+			 const struct clk_master_layout *layout)
+{
+	struct clk *clk;
+	int num_parents;
+	int i;
+	unsigned int irq;
+	const char *parent_names[MASTER_SOURCE_MAX];
+	const char *name = np->name;
+	struct clk_master_characteristics *characteristics;
+
+	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+	if (num_parents <= 0 || num_parents > MASTER_SOURCE_MAX)
+		return;
+
+	for (i = 0; i < num_parents; ++i) {
+		parent_names[i] = of_clk_get_parent_name(np, i);
+		if (!parent_names[i])
+			return;
+	}
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	characteristics = of_at91_clk_master_get_characteristics(np);
+	if (!characteristics)
+		return;
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq)
+		return;
+
+	clk = at91_clk_register_master(pmc, irq, name, num_parents,
+				       parent_names, layout,
+				       characteristics);
+	if (IS_ERR(clk))
+		goto out_free_characteristics;
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	return;
+
+out_free_characteristics:
+	kfree(characteristics);
+}
+
+void __init of_at91rm9200_clk_master_setup(struct device_node *np,
+					   struct at91_pmc *pmc)
+{
+	of_at91_clk_master_setup(np, pmc, &at91rm9200_master_layout);
+}
+
+void __init of_at91sam9x5_clk_master_setup(struct device_node *np,
+					   struct at91_pmc *pmc)
+{
+	of_at91_clk_master_setup(np, pmc, &at91sam9x5_master_layout);
+}
diff --git a/drivers/clk/at91/clk-pll.c b/drivers/clk/at91/clk-pll.c
index 57cedb5..c4d0dc8 100644
--- a/drivers/clk/at91/clk-pll.c
+++ b/drivers/clk/at91/clk-pll.c
@@ -82,6 +82,8 @@  static int clk_pll_prepare(struct clk_hw *hw)
 	struct clk_pll *pll = to_clk_pll(hw);
 	struct at91_pmc *pmc = pll->pmc;
 	const struct clk_pll_layout *layout = pll->layout;
+	const struct clk_pll_characteristics *characteristics =
+							pll->characteristics;
 	u8 id = pll->id;
 	u32 mask = PLL_STATUS_MASK(id);
 	int offset = PLL_REG(id);
@@ -271,18 +273,10 @@  static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 			    unsigned long parent_rate)
 {
 	struct clk_pll *pll = to_clk_pll(hw);
-	struct at91_pmc *pmc = pll->pmc;
-	const struct clk_pll_layout *layout = pll->layout;
-	const struct clk_pll_characteristics *characteristics =
-						pll->characteristics;
-	u8 id = pll->id;
-	int offset = PLL_REG(id);
 	long ret;
 	u32 div;
 	u32 mul;
 	u32 index;
-	u32 tmp;
-	u8 out = 0;
 
 	ret = clk_pll_get_best_div_mul(pll, rate, parent_rate,
 				       &div, &mul, &index);
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index d26fdb7..d9975e7 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -257,6 +257,15 @@  static const struct of_device_id pmc_clk_ids[] __initdata = {
 		.compatible = "atmel,at91sam9x5-clk-plldiv",
 		.data = of_at91sam9x5_clk_plldiv_setup,
 	},
+	/* Master clock */
+	{
+		.compatible = "atmel,at91rm9200-clk-master",
+		.data = of_at91rm9200_clk_master_setup,
+	},
+	{
+		.compatible = "atmel,at91sam9x5-clk-master",
+		.data = of_at91sam9x5_clk_master_setup,
+	},
 	{ /*sentinel*/ }
 };
 
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index 15aaf38..be5c964 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -72,4 +72,9 @@  extern void __init of_sama5d3_clk_pll_setup(struct device_node *np,
 extern void __init of_at91sam9x5_clk_plldiv_setup(struct device_node *np,
 						  struct at91_pmc *pmc);
 
+extern void __init of_at91rm9200_clk_master_setup(struct device_node *np,
+						  struct at91_pmc *pmc);
+extern void __init of_at91sam9x5_clk_master_setup(struct device_node *np,
+						  struct at91_pmc *pmc);
+
 #endif /* __PMC_H_ */