[PATCH v6 10/16] clk: at91: add PMC programmable clocks
Boris BREZILLON
b.brezillon at overkiz.com
Thu Nov 28 08:37:55 EST 2013
This patch adds new at91 programmable clocks implementation using common clk
framework.
A programmable clock is a clock which can be exported on a given pin to clock
external devices.
Each programmable clock is given an id (from 0 to 8).
The number of available programmable clocks depends on the SoC you're using.
Programmable clock driver only implements the clock setting (clock rate and
parent setting). It must be chained to a system clock in order to
enable/disable the generated clock.
The PCKX pins used to output the clock signals must be assigned to the
appropriate peripheral (see atmel's datasheets).
Signed-off-by: Boris BREZILLON <b.brezillon at overkiz.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
---
drivers/clk/at91/Makefile | 2 +
drivers/clk/at91/clk-programmable.c | 366 +++++++++++++++++++++++++++++++++++
drivers/clk/at91/pmc.c | 15 ++
drivers/clk/at91/pmc.h | 9 +
4 files changed, 392 insertions(+)
create mode 100644 drivers/clk/at91/clk-programmable.c
diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
index 04deba3..3873b62 100644
--- a/drivers/clk/at91/Makefile
+++ b/drivers/clk/at91/Makefile
@@ -5,3 +5,5 @@
obj-y += pmc.o
obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o
obj-y += clk-system.o clk-peripheral.o
+
+obj-$(CONFIG_AT91_PROGRAMMABLE_CLOCKS) += clk-programmable.o
diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
new file mode 100644
index 0000000..fd792b2
--- /dev/null
+++ b/drivers/clk/at91/clk-programmable.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (C) 2013 Boris BREZILLON <b.brezillon at 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/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 PROG_SOURCE_MAX 5
+#define PROG_ID_MAX 7
+
+#define PROG_STATUS_MASK(id) (1 << ((id) + 8))
+#define PROG_PRES_MASK 0x7
+#define PROG_MAX_RM9200_CSS 3
+
+struct clk_programmable_layout {
+ u8 pres_shift;
+ u8 css_mask;
+ u8 have_slck_mck;
+};
+
+struct clk_programmable {
+ struct clk_hw hw;
+ struct at91_pmc *pmc;
+ unsigned int irq;
+ wait_queue_head_t wait;
+ u8 id;
+ u8 css;
+ u8 pres;
+ u8 slckmck;
+ const struct clk_programmable_layout *layout;
+};
+
+#define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
+
+
+static irqreturn_t clk_programmable_irq_handler(int irq, void *dev_id)
+{
+ struct clk_programmable *prog = (struct clk_programmable *)dev_id;
+
+ wake_up(&prog->wait);
+
+ return IRQ_HANDLED;
+}
+
+static int clk_programmable_prepare(struct clk_hw *hw)
+{
+ u32 tmp;
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ struct at91_pmc *pmc = prog->pmc;
+ const struct clk_programmable_layout *layout = prog->layout;
+ u8 id = prog->id;
+ u32 mask = PROG_STATUS_MASK(id);
+
+ tmp = prog->css | (prog->pres << layout->pres_shift);
+ if (layout->have_slck_mck && prog->slckmck)
+ tmp |= AT91_PMC_CSSMCK_MCK;
+
+ pmc_write(pmc, AT91_PMC_PCKR(id), tmp);
+
+ while (!(pmc_read(pmc, AT91_PMC_SR) & mask))
+ wait_event(prog->wait, pmc_read(pmc, AT91_PMC_SR) & mask);
+
+ return 0;
+}
+
+static int clk_programmable_is_ready(struct clk_hw *hw)
+{
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ struct at91_pmc *pmc = prog->pmc;
+
+ return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_PCKR(prog->id));
+}
+
+static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ u32 tmp;
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ struct at91_pmc *pmc = prog->pmc;
+ const struct clk_programmable_layout *layout = prog->layout;
+
+ tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
+ prog->pres = (tmp >> layout->pres_shift) & PROG_PRES_MASK;
+
+ return parent_rate >> prog->pres;
+}
+
+static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ unsigned long best_rate = *parent_rate;
+ unsigned long best_diff;
+ unsigned long new_diff;
+ unsigned long cur_rate;
+ int shift = shift;
+
+ if (rate > *parent_rate)
+ return *parent_rate;
+ else
+ best_diff = *parent_rate - rate;
+
+ if (!best_diff)
+ return best_rate;
+
+ for (shift = 1; shift < PROG_PRES_MASK; shift++) {
+ cur_rate = *parent_rate >> shift;
+
+ if (cur_rate > rate)
+ new_diff = cur_rate - rate;
+ else
+ new_diff = rate - cur_rate;
+
+ if (!new_diff)
+ return cur_rate;
+
+ if (new_diff < best_diff) {
+ best_diff = new_diff;
+ best_rate = cur_rate;
+ }
+
+ if (rate > cur_rate)
+ break;
+ }
+
+ return best_rate;
+}
+
+static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ const struct clk_programmable_layout *layout = prog->layout;
+ if (index > layout->css_mask) {
+ if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
+ prog->css = 0;
+ prog->slckmck = 1;
+ return 0;
+ } else {
+ return -EINVAL;
+ }
+ }
+
+ prog->css = index;
+ return 0;
+}
+
+static u8 clk_programmable_get_parent(struct clk_hw *hw)
+{
+ u32 tmp;
+ u8 ret;
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ struct at91_pmc *pmc = prog->pmc;
+ const struct clk_programmable_layout *layout = prog->layout;
+
+ tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
+ prog->css = tmp & layout->css_mask;
+ ret = prog->css;
+ if (layout->have_slck_mck) {
+ prog->slckmck = !!(tmp & AT91_PMC_CSSMCK_MCK);
+ if (prog->slckmck && !ret)
+ ret = PROG_MAX_RM9200_CSS + 1;
+ }
+
+ return ret;
+}
+
+static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_programmable *prog = to_clk_programmable(hw);
+ unsigned long best_rate = parent_rate;
+ unsigned long best_diff;
+ unsigned long new_diff;
+ unsigned long cur_rate;
+ int shift = 0;
+
+ if (rate > parent_rate)
+ return parent_rate;
+ else
+ best_diff = parent_rate - rate;
+
+ if (!best_diff) {
+ prog->pres = shift;
+ return 0;
+ }
+
+ for (shift = 1; shift < PROG_PRES_MASK; shift++) {
+ cur_rate = parent_rate >> shift;
+
+ if (cur_rate > rate)
+ new_diff = cur_rate - rate;
+ else
+ new_diff = rate - cur_rate;
+
+ if (!new_diff)
+ break;
+
+ if (new_diff < best_diff) {
+ best_diff = new_diff;
+ best_rate = cur_rate;
+ }
+
+ if (rate > cur_rate)
+ break;
+ }
+
+ prog->pres = shift;
+ return 0;
+}
+
+static const struct clk_ops programmable_ops = {
+ .prepare = clk_programmable_prepare,
+ .is_prepared = clk_programmable_is_ready,
+ .recalc_rate = clk_programmable_recalc_rate,
+ .round_rate = clk_programmable_round_rate,
+ .get_parent = clk_programmable_get_parent,
+ .set_parent = clk_programmable_set_parent,
+ .set_rate = clk_programmable_set_rate,
+};
+
+static struct clk * __init
+at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
+ const char *name, const char **parent_names,
+ u8 num_parents, u8 id,
+ const struct clk_programmable_layout *layout)
+{
+ int ret;
+ struct clk_programmable *prog;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+ char irq_name[11];
+
+ if (id > PROG_ID_MAX)
+ return ERR_PTR(-EINVAL);
+
+ prog = kzalloc(sizeof(*prog), GFP_KERNEL);
+ if (!prog)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &programmable_ops;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+ init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+
+ prog->id = id;
+ prog->layout = layout;
+ prog->hw.init = &init;
+ prog->pmc = pmc;
+ prog->irq = irq;
+ init_waitqueue_head(&prog->wait);
+ irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);
+ snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);
+ ret = request_irq(prog->irq, clk_programmable_irq_handler,
+ IRQF_TRIGGER_HIGH, irq_name, prog);
+ if (ret)
+ return ERR_PTR(ret);
+
+ clk = clk_register(NULL, &prog->hw);
+ if (IS_ERR(clk))
+ kfree(prog);
+
+ return clk;
+}
+
+static const struct clk_programmable_layout at91rm9200_programmable_layout = {
+ .pres_shift = 2,
+ .css_mask = 0x3,
+ .have_slck_mck = 0,
+};
+
+static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
+ .pres_shift = 2,
+ .css_mask = 0x3,
+ .have_slck_mck = 1,
+};
+
+static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
+ .pres_shift = 4,
+ .css_mask = 0x7,
+ .have_slck_mck = 0,
+};
+
+static void __init
+of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
+ const struct clk_programmable_layout *layout)
+{
+ int num;
+ u32 id;
+ int i;
+ unsigned int irq;
+ struct clk *clk;
+ int num_parents;
+ const char *parent_names[PROG_SOURCE_MAX];
+ const char *name;
+ struct device_node *progclknp;
+
+ num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+ if (num_parents <= 0 || num_parents > PROG_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;
+ }
+
+ num = of_get_child_count(np);
+ if (!num || num > (PROG_ID_MAX + 1))
+ return;
+
+ for_each_child_of_node(np, progclknp) {
+ if (of_property_read_u32(progclknp, "reg", &id))
+ continue;
+
+ if (of_property_read_string(np, "clock-output-names", &name))
+ name = progclknp->name;
+
+ irq = irq_of_parse_and_map(progclknp, 0);
+ if (!irq)
+ continue;
+
+ clk = at91_clk_register_programmable(pmc, irq, name,
+ parent_names, num_parents,
+ id, layout);
+ if (IS_ERR(clk))
+ continue;
+
+ of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
+ }
+}
+
+
+void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
+}
+
+void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
+}
+
+void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
+}
diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
index afdfeb2..d0a1f93 100644
--- a/drivers/clk/at91/pmc.c
+++ b/drivers/clk/at91/pmc.c
@@ -278,6 +278,21 @@ static const struct of_device_id pmc_clk_ids[] __initdata = {
.compatible = "atmel,at91sam9x5-clk-peripheral",
.data = of_at91sam9x5_clk_periph_setup,
},
+ /* Programmable clocks */
+#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)
+ {
+ .compatible = "atmel,at91rm9200-clk-programmable",
+ .data = of_at91rm9200_clk_prog_setup,
+ },
+ {
+ .compatible = "atmel,at91sam9g45-clk-programmable",
+ .data = of_at91sam9g45_clk_prog_setup,
+ },
+ {
+ .compatible = "atmel,at91sam9x5-clk-programmable",
+ .data = of_at91sam9x5_clk_prog_setup,
+ },
+#endif
{ /*sentinel*/ }
};
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index a09212b..6eeed49 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -85,4 +85,13 @@ extern void __init of_at91rm9200_clk_periph_setup(struct device_node *np,
extern void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,
struct at91_pmc *pmc);
+#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)
+extern void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc);
+extern void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc);
+extern void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
+ struct at91_pmc *pmc);
+#endif
+
#endif /* __PMC_H_ */
--
1.7.9.5
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