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Date: Fri, 7 Jun 2013 10:34:15 +0200
From: Boris BREZILLON <b.brezillon@...rkiz.com>
To: Mike Turquette <mturquette@...aro.org>,
Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
Nicolas Ferre <nicolas.ferre@...el.com>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: Boris BREZILLON <b.brezillon@...rkiz.com>
Subject: [RFC 04/50] ARM: at91: add PMC master clock support using common clk framework.
This is the at91 master clock implementation using common clk framework.
The pll clock layout describe the MCKR register layout.
There's four pll 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 <b.brezillon@...rkiz.com>
---
drivers/clk/at91/Makefile | 2 +-
drivers/clk/at91/clk-master.c | 317 +++++++++++++++++++++++++++++++++++++++++
include/linux/clk/at91.h | 23 +++
3 files changed, 341 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 564076f..d41f616 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -2,4 +2,4 @@
# Makefile for at91 specific clk
#
-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..71ade7d
--- /dev/null
+++ b/drivers/clk/at91/clk-master.c
@@ -0,0 +1,317 @@
+/*
+ * drivers/clk/at91/clk-master.c
+ *
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon@...rkiz.com>
+ *
+ * This masterram 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 MASTER_SOURCE_MAX 4
+
+#define to_clk_master(hw) container_of(hw, struct clk_master, hw)
+
+struct clk_master {
+ struct clk_hw hw;
+ struct clk_master_layout *layout;
+ struct clk_master_characteristics *characteristics;
+};
+
+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 clk_master_layout *layout = master->layout;
+ struct clk_master_characteristics *characteristics =
+ master->characteristics;
+ u32 tmp = at91_pmc_read(AT91_PMC_MCKR) & layout->mask;
+
+ pres = (tmp >> layout->pres_shift) & 0x7;
+ div = (tmp >> 8) & 0x3;
+
+ if (characteristics->have_div3_pres && pres == 7)
+ rate /= 3;
+ else
+ rate >>= pres;
+
+ rate /= characteristics->divisors[div];
+
+ /* print overclocking or underclocking error */
+ /*
+ if (rate < characteristics->output.min ||
+ rate > characteristics->output.max) {
+ }
+ */
+ return rate;
+}
+
+static long clk_master_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ int mdiv;
+ int pres;
+ u32 div;
+ long best_rate = -EINVAL;
+ unsigned long best_diff = 0;
+ unsigned long cur_diff;
+ unsigned long pres_rate;
+ unsigned long cur_rate;
+ struct clk_master *master = to_clk_master(hw);
+ struct clk_master_characteristics *characteristics =
+ master->characteristics;
+
+ if (rate < characteristics->output.min ||
+ rate > characteristics->output.max)
+ return -EINVAL;
+
+ for (pres = 0; pres < 7; pres++) {
+ if (pres < 7)
+ pres_rate = *parent_rate >> pres;
+ else {
+ if (!characteristics->have_div3_pres)
+ break;
+ pres_rate = *parent_rate / 3;
+ }
+ for (mdiv = 0; mdiv < 4; mdiv++) {
+ div = characteristics->divisors[mdiv];
+ if (!div)
+ continue;
+ cur_rate = pres_rate / div;
+ if (rate < cur_rate)
+ cur_diff = cur_rate - rate;
+ else
+ cur_diff = rate - cur_rate;
+
+ if (best_rate < 0 || cur_diff < best_diff) {
+ best_rate = cur_rate;
+ best_diff = cur_diff;
+ if (!best_diff)
+ return best_rate;
+ }
+ }
+ }
+
+ return best_rate;
+}
+
+static int clk_master_set_parent(struct clk_hw *hw, u8 index)
+{
+ u32 tmp;
+ if (index > AT91_PMC_CSS)
+ return -EINVAL;
+ tmp = at91_pmc_read(AT91_PMC_MCKR) & ~AT91_PMC_CSS;
+ tmp |= index;
+
+ at91_pmc_write(AT91_PMC_MCKR, tmp);
+ while (!(at91_pmc_read(AT91_PMC_SR) & AT91_PMC_MCKRDY))
+ ;
+ return 0;
+}
+
+static u8 clk_master_get_parent(struct clk_hw *hw)
+{
+ return at91_pmc_read(AT91_PMC_MCKR) & AT91_PMC_CSS;
+}
+
+static int clk_master_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ int mdiv;
+ int pres;
+ u32 div;
+ u32 tmp;
+ unsigned long cur_rate;
+ unsigned long pres_rate;
+ struct clk_master *master = to_clk_master(hw);
+ struct clk_master_layout *layout = master->layout;
+ struct clk_master_characteristics *characteristics =
+ master->characteristics;
+ for (pres = 0; pres < 7; pres++) {
+ if (pres < 7)
+ pres_rate = parent_rate >> pres;
+ else {
+ if (!characteristics->have_div3_pres)
+ break;
+ pres_rate = parent_rate / 3;
+ }
+ for (mdiv = 0; mdiv < 4; mdiv++) {
+ div = characteristics->divisors[mdiv];
+ if (!div)
+ continue;
+ cur_rate = pres_rate / div;
+ if (cur_rate == rate) {
+ tmp = at91_pmc_read(AT91_PMC_MCKR);
+ tmp &= layout->mask;
+ tmp &= ~AT91_PMC_CSS;
+ tmp |= pres << layout->pres_shift | mdiv << 8;
+
+ at91_pmc_write(AT91_PMC_MCKR, tmp);
+ while (!(at91_pmc_read(AT91_PMC_SR) &
+ AT91_PMC_MCKRDY))
+ ;
+ return 0;
+ }
+ }
+ }
+
+ return -EINVAL;
+}
+
+static const struct clk_ops master_ops = {
+ .recalc_rate = clk_master_recalc_rate,
+ .round_rate = clk_master_round_rate,
+ .get_parent = clk_master_get_parent,
+ .set_parent = clk_master_set_parent,
+ .set_rate = clk_master_set_rate,
+};
+
+struct clk * __init
+at91_clk_register_master(const char *name,
+ int num_parents,
+ const char **parent_names,
+ struct clk_master_layout *layout,
+ struct clk_master_characteristics *characteristics)
+{
+ struct clk_master *master;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ 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 = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+
+ master->hw.init = &init;
+ master->layout = layout;
+ master->characteristics = characteristics;
+
+ clk = clk_register(NULL, &master->hw);
+
+ if (IS_ERR(clk))
+ kfree(master);
+
+ return clk;
+}
+
+
+struct clk_master_layout at91rm9200_master_layout = {
+ .mask = 0x31F,
+ .pres_shift = 2,
+};
+
+struct clk_master_layout at91sam9x5_master_layout = {
+ .mask = 0x373,
+ .pres_shift = 4,
+};
+
+
+#if defined(CONFIG_OF)
+static struct clk_master_characteristics * __init
+of_at91_clk_master_get_characteristics(struct device_node *np)
+{
+ int i;
+ u32 tmp;
+ struct clk_master_characteristics *characteristics = NULL;
+
+ characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL);
+ if (!characteristics)
+ return NULL;
+
+ if (of_property_read_u32_index(np, "output", 0, &tmp))
+ goto out_free_characteristics;
+
+ characteristics->output.min = tmp;
+
+ if (of_property_read_u32_index(np, "output", 1, &tmp))
+ goto out_free_characteristics;
+
+ characteristics->output.max = tmp;
+
+ for (i = 0; i < 4; i++) {
+ tmp = 0;
+ of_property_read_u32_index(np, "divisors", i, &tmp);
+ characteristics->divisors[i] = tmp;
+ }
+
+ characteristics->have_div3_pres =
+ of_property_read_bool(np, "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 clk_master_layout *layout)
+{
+ struct clk *clk;
+ int num_parents;
+ int i;
+ 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;
+
+ clk = at91_clk_register_master(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);
+}
+
+static void __init of_at91rm9200_clk_master_setup(struct device_node *np)
+{
+ of_at91_clk_master_setup(np, &at91rm9200_master_layout);
+}
+CLK_OF_DECLARE(at91rm9200_clk_master, "atmel,at91rm9200-clk-master",
+ of_at91rm9200_clk_master_setup);
+
+static void __init of_at91sam9x5_clk_master_setup(struct device_node *np)
+{
+ of_at91_clk_master_setup(np, &at91sam9x5_master_layout);
+}
+CLK_OF_DECLARE(at91sam9x5_clk_master, "atmel,at91sam9x5-clk-master",
+ of_at91sam9x5_clk_master_setup);
+#endif
diff --git a/include/linux/clk/at91.h b/include/linux/clk/at91.h
index 7ba038f..a960e2f 100644
--- a/include/linux/clk/at91.h
+++ b/include/linux/clk/at91.h
@@ -210,6 +210,17 @@ struct clk_pll_layout {
u8 mul_shift;
};
+struct clk_master_characteristics {
+ struct clk_range output;
+ u32 divisors[4];
+ u8 have_div3_pres;
+};
+
+struct clk_master_layout {
+ u32 mask;
+ u8 pres_shift;
+};
+
struct clk * __init
at91_clk_register_main(const char *name,
@@ -233,4 +244,16 @@ at91_clk_register_pll(const char *name, const char *parent_name, u8 id,
struct clk * __init
at91_clk_register_plldiv(const char *name, const char *parent_name);
+
+extern struct clk_master_layout at91rm9200_master_layout;
+
+extern struct clk_master_layout at91sam9x5_master_layout;
+
+struct clk * __init
+at91_clk_register_master(const char *name, int num_parents,
+ const char **parent_names,
+ struct clk_master_layout *layout,
+ struct clk_master_characteristics *characteristics);
+
+
#endif
--
1.7.9.5
--
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