--- /dev/null
+/*
+ * drivers/clk/at91/clk-slow.c
+ *
+ * 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/delay.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+
+#include "pmc.h"
+#include "sckc.h"
+
+#define SLOW_CLOCK_FREQ 32768
+#define SLOWCK_SW_CYCLES 5
+#define SLOWCK_SW_TIME_USEC ((SLOWCK_SW_CYCLES * USEC_PER_SEC) / \
+ SLOW_CLOCK_FREQ)
+
+#define AT91_SCKC_CR 0x00
+#define AT91_SCKC_RCEN (1 << 0)
+#define AT91_SCKC_OSC32EN (1 << 1)
+#define AT91_SCKC_OSC32BYP (1 << 2)
+#define AT91_SCKC_OSCSEL (1 << 3)
+
+struct clk_slow_osc {
+ struct clk_hw hw;
+ void __iomem *sckcr;
+ unsigned long startup_usec;
+};
+
+#define to_clk_slow_osc(hw) container_of(hw, struct clk_slow_osc, hw)
+
+struct clk_slow_rc_osc {
+ struct clk_hw hw;
+ void __iomem *sckcr;
+ unsigned long frequency;
+ unsigned long accuracy;
+ unsigned long startup_usec;
+};
+
+#define to_clk_slow_rc_osc(hw) container_of(hw, struct clk_slow_rc_osc, hw)
+
+struct clk_sam9260_slow {
+ struct clk_hw hw;
+ struct at91_pmc *pmc;
+};
+
+#define to_clk_sam9260_slow(hw) container_of(hw, struct clk_sam9260_slow, hw)
+
+struct clk_sam9x5_slow {
+ struct clk_hw hw;
+ void __iomem *sckcr;
+ u8 parent;
+};
+
+#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)
+
+static struct clk *slow_clk;
+
+static int clk_slow_osc_prepare(struct clk_hw *hw)
+{
+ struct clk_slow_osc *osc = to_clk_slow_osc(hw);
+ void __iomem *sckcr = osc->sckcr;
+ u32 tmp = readl(sckcr);
+
+ if (tmp & AT91_SCKC_OSC32BYP)
+ return 0;
+
+ writel(tmp | AT91_SCKC_OSC32EN, sckcr);
+
+ usleep_range(osc->startup_usec, osc->startup_usec + 1);
+
+ return 0;
+}
+
+static void clk_slow_osc_unprepare(struct clk_hw *hw)
+{
+ struct clk_slow_osc *osc = to_clk_slow_osc(hw);
+ void __iomem *sckcr = osc->sckcr;
+ u32 tmp = readl(sckcr);
+
+ if (tmp & AT91_SCKC_OSC32BYP)
+ return;
+
+ writel(tmp & ~AT91_SCKC_OSC32EN, sckcr);
+}
+
+static int clk_slow_osc_is_prepared(struct clk_hw *hw)
+{
+ struct clk_slow_osc *osc = to_clk_slow_osc(hw);
+ void __iomem *sckcr = osc->sckcr;
+ u32 tmp = readl(sckcr);
+
+ if (tmp & AT91_SCKC_OSC32BYP)
+ return 1;
+
+ return !!(tmp & AT91_SCKC_OSC32EN);
+}
+
+static const struct clk_ops slow_osc_ops = {
+ .prepare = clk_slow_osc_prepare,
+ .unprepare = clk_slow_osc_unprepare,
+ .is_prepared = clk_slow_osc_is_prepared,
+};
+
+static struct clk * __init
+at91_clk_register_slow_osc(void __iomem *sckcr,
+ const char *name,
+ const char *parent_name,
+ unsigned long startup,
+ bool bypass)
+{
+ struct clk_slow_osc *osc;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!sckcr || !name || !parent_name)
+ return ERR_PTR(-EINVAL);
+
+ osc = kzalloc(sizeof(*osc), GFP_KERNEL);
+ if (!osc)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &slow_osc_ops;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ init.flags = CLK_IGNORE_UNUSED;
+
+ osc->hw.init = &init;
+ osc->sckcr = sckcr;
+ osc->startup_usec = startup;
+
+ if (bypass)
+ writel((readl(sckcr) & ~AT91_SCKC_OSC32EN) | AT91_SCKC_OSC32BYP,
+ sckcr);
+
+ clk = clk_register(NULL, &osc->hw);
+ if (IS_ERR(clk))
+ kfree(osc);
+
+ return clk;
+}
+
+void __init of_at91sam9x5_clk_slow_osc_setup(struct device_node *np,
+ void __iomem *sckcr)
+{
+ struct clk *clk;
+ const char *parent_name;
+ const char *name = np->name;
+ u32 startup;
+ bool bypass;
+
+ parent_name = of_clk_get_parent_name(np, 0);
+ of_property_read_string(np, "clock-output-names", &name);
+ of_property_read_u32(np, "atmel,startup-time-usec", &startup);
+ bypass = of_property_read_bool(np, "atmel,osc-bypass");
+
+ clk = at91_clk_register_slow_osc(sckcr, name, parent_name, startup,
+ bypass);
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
+
+ return osc->frequency;
+}
+
+static unsigned long clk_slow_rc_osc_recalc_accuracy(struct clk_hw *hw,
+ unsigned long parent_acc)
+{
+ struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
+
+ return osc->accuracy;
+}
+
+static int clk_slow_rc_osc_prepare(struct clk_hw *hw)
+{
+ struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
+ void __iomem *sckcr = osc->sckcr;
+
+ writel(readl(sckcr) | AT91_SCKC_RCEN, sckcr);
+
+ usleep_range(osc->startup_usec, osc->startup_usec + 1);
+
+ return 0;
+}
+
+static void clk_slow_rc_osc_unprepare(struct clk_hw *hw)
+{
+ struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
+ void __iomem *sckcr = osc->sckcr;
+
+ writel(readl(sckcr) & ~AT91_SCKC_RCEN, sckcr);
+}
+
+static int clk_slow_rc_osc_is_prepared(struct clk_hw *hw)
+{
+ struct clk_slow_rc_osc *osc = to_clk_slow_rc_osc(hw);
+
+ return !!(readl(osc->sckcr) & AT91_SCKC_RCEN);
+}
+
+static const struct clk_ops slow_rc_osc_ops = {
+ .prepare = clk_slow_rc_osc_prepare,
+ .unprepare = clk_slow_rc_osc_unprepare,
+ .is_prepared = clk_slow_rc_osc_is_prepared,
+ .recalc_rate = clk_slow_rc_osc_recalc_rate,
+ .recalc_accuracy = clk_slow_rc_osc_recalc_accuracy,
+};
+
+static struct clk * __init
+at91_clk_register_slow_rc_osc(void __iomem *sckcr,
+ const char *name,
+ unsigned long frequency,
+ unsigned long accuracy,
+ unsigned long startup)
+{
+ struct clk_slow_rc_osc *osc;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!sckcr || !name)
+ return ERR_PTR(-EINVAL);
+
+ osc = kzalloc(sizeof(*osc), GFP_KERNEL);
+ if (!osc)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &slow_rc_osc_ops;
+ init.parent_names = NULL;
+ init.num_parents = 0;
+ init.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED;
+
+ osc->hw.init = &init;
+ osc->sckcr = sckcr;
+ osc->frequency = frequency;
+ osc->accuracy = accuracy;
+ osc->startup_usec = startup;
+
+ clk = clk_register(NULL, &osc->hw);
+ if (IS_ERR(clk))
+ kfree(osc);
+
+ return clk;
+}
+
+void __init of_at91sam9x5_clk_slow_rc_osc_setup(struct device_node *np,
+ void __iomem *sckcr)
+{
+ struct clk *clk;
+ u32 frequency = 0;
+ u32 accuracy = 0;
+ u32 startup = 0;
+ const char *name = np->name;
+
+ of_property_read_string(np, "clock-output-names", &name);
+ of_property_read_u32(np, "clock-frequency", &frequency);
+ of_property_read_u32(np, "clock-accuracy", &accuracy);
+ of_property_read_u32(np, "atmel,startup-time-usec", &startup);
+
+ clk = at91_clk_register_slow_rc_osc(sckcr, name, frequency, accuracy,
+ startup);
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
+ void __iomem *sckcr = slowck->sckcr;
+ u32 tmp;
+
+ if (index > 1)
+ return -EINVAL;
+
+ tmp = readl(sckcr);
+
+ if ((!index && !(tmp & AT91_SCKC_OSCSEL)) ||
+ (index && (tmp & AT91_SCKC_OSCSEL)))
+ return 0;
+
+ if (index)
+ tmp |= AT91_SCKC_OSCSEL;
+ else
+ tmp &= ~AT91_SCKC_OSCSEL;
+
+ writel(tmp, sckcr);
+
+ usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
+
+ return 0;
+}
+
+static u8 clk_sam9x5_slow_get_parent(struct clk_hw *hw)
+{
+ struct clk_sam9x5_slow *slowck = to_clk_sam9x5_slow(hw);
+
+ return !!(readl(slowck->sckcr) & AT91_SCKC_OSCSEL);
+}
+
+static const struct clk_ops sam9x5_slow_ops = {
+ .set_parent = clk_sam9x5_slow_set_parent,
+ .get_parent = clk_sam9x5_slow_get_parent,
+};
+
+static struct clk * __init
+at91_clk_register_sam9x5_slow(void __iomem *sckcr,
+ const char *name,
+ const char **parent_names,
+ int num_parents)
+{
+ struct clk_sam9x5_slow *slowck;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!sckcr || !name || !parent_names || !num_parents)
+ return ERR_PTR(-EINVAL);
+
+ slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
+ if (!slowck)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &sam9x5_slow_ops;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+ init.flags = 0;
+
+ slowck->hw.init = &init;
+ slowck->sckcr = sckcr;
+ slowck->parent = !!(readl(sckcr) & AT91_SCKC_OSCSEL);
+
+ clk = clk_register(NULL, &slowck->hw);
+ if (IS_ERR(clk))
+ kfree(slowck);
+ else
+ slow_clk = clk;
+
+ return clk;
+}
+
+void __init of_at91sam9x5_clk_slow_setup(struct device_node *np,
+ void __iomem *sckcr)
+{
+ struct clk *clk;
+ const char *parent_names[2];
+ int num_parents;
+ const char *name = np->name;
+ int i;
+
+ num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+ if (num_parents <= 0 || num_parents > 2)
+ 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);
+
+ clk = at91_clk_register_sam9x5_slow(sckcr, name, parent_names,
+ num_parents);
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static u8 clk_sam9260_slow_get_parent(struct clk_hw *hw)
+{
+ struct clk_sam9260_slow *slowck = to_clk_sam9260_slow(hw);
+
+ return !!(pmc_read(slowck->pmc, AT91_PMC_SR) & AT91_PMC_OSCSEL);
+}
+
+static const struct clk_ops sam9260_slow_ops = {
+ .get_parent = clk_sam9260_slow_get_parent,
+};
+
+static struct clk * __init
+at91_clk_register_sam9260_slow(struct at91_pmc *pmc,
+ const char *name,
+ const char **parent_names,
+ int num_parents)
+{
+ struct clk_sam9260_slow *slowck;
+ struct clk *clk = NULL;
+ struct clk_init_data init;
+
+ if (!pmc || !name)
+ return ERR_PTR(-EINVAL);
+
+ if (!parent_names || !num_parents)
+ return ERR_PTR(-EINVAL);
+
+ slowck = kzalloc(sizeof(*slowck), GFP_KERNEL);
+ if (!slowck)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &sam9260_slow_ops;
+ init.parent_names = parent_names;
+ init.num_parents = num_parents;
+ init.flags = 0;
+
+ slowck->hw.init = &init;
+ slowck->pmc = pmc;
+
+ clk = clk_register(NULL, &slowck->hw);
+ if (IS_ERR(clk))
+ kfree(slowck);
+ else
+ slow_clk = clk;
+
+ return clk;
+}
+
+void __init of_at91sam9260_clk_slow_setup(struct device_node *np,
+ struct at91_pmc *pmc)
+{
+ struct clk *clk;
+ const char *parent_names[2];
+ int num_parents;
+ const char *name = np->name;
+ int i;
+
+ num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+ if (num_parents != 2)
+ 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);
+
+ clk = at91_clk_register_sam9260_slow(pmc, name, parent_names,
+ num_parents);
+ if (IS_ERR(clk))
+ return;
+
+ of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+/*
+ * FIXME: All slow clk users are not properly claiming it (get + prepare +
+ * enable) before using it.
+ * If all users properly claiming this clock decide that they don't need it
+ * anymore (or are removed), it is disabled while faulty users are still
+ * requiring it, and the system hangs.
+ * Prevent this clock from being disabled until all users are properly
+ * requesting it.
+ * Once this is done we should remove this function and the slow_clk variable.
+ */
+static int __init of_at91_clk_slow_retain(void)
+{
+ if (!slow_clk)
+ return 0;
+
+ __clk_get(slow_clk);
+ clk_prepare_enable(slow_clk);
+
+ return 0;
+}
+arch_initcall(of_at91_clk_slow_retain);
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