Added missing tegra files.HEADmaster

1 files changed, 846 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/dvfs.c b/arch/arm/mach-tegra/dvfs.c
new file mode 100644
index 00000000000..8723e6fa60d
--- /dev/null
+++ b/arch/arm/mach-tegra/dvfs.c
@@ -0,0 +1,846 @@
+/*
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * Author:
+ *      Colin Cross <ccross@google.com>
+ *
+ * Copyright (C) 2010-2011 NVIDIA Corporation.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/debugfs.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/suspend.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+
+#include <mach/clk.h>
+
+#include "board.h"
+#include "clock.h"
+#include "dvfs.h"
+
+#define DVFS_RAIL_STATS_BIN     25
+#define DVFS_RAIL_STATS_SCALE   2
+#define DVFS_RAIL_STATS_RANGE   ((DVFS_RAIL_STATS_TOP_BIN - 1) * \
+                                 DVFS_RAIL_STATS_BIN / DVFS_RAIL_STATS_SCALE)
+
+static LIST_HEAD(dvfs_rail_list);
+static DEFINE_MUTEX(dvfs_lock);
+static DEFINE_MUTEX(rail_disable_lock);
+
+static int dvfs_rail_update(struct dvfs_rail *rail);
+
+void tegra_dvfs_add_relationships(struct dvfs_relationship *rels, int n)
+{
+        int i;
+        struct dvfs_relationship *rel;
+
+        mutex_lock(&dvfs_lock);
+
+        for (i = 0; i < n; i++) {
+                rel = &rels[i];
+                list_add_tail(&rel->from_node, &rel->to->relationships_from);
+                list_add_tail(&rel->to_node, &rel->from->relationships_to);
+        }
+
+        mutex_unlock(&dvfs_lock);
+}
+
+int tegra_dvfs_init_rails(struct dvfs_rail *rails[], int n)
+{
+        int i;
+
+        mutex_lock(&dvfs_lock);
+
+        for (i = 0; i < n; i++) {
+                INIT_LIST_HEAD(&rails[i]->dvfs);
+                INIT_LIST_HEAD(&rails[i]->relationships_from);
+                INIT_LIST_HEAD(&rails[i]->relationships_to);
+                rails[i]->millivolts = rails[i]->nominal_millivolts;
+                rails[i]->new_millivolts = rails[i]->nominal_millivolts;
+                if (!rails[i]->step)
+                        rails[i]->step = rails[i]->max_millivolts;
+
+                list_add_tail(&rails[i]->node, &dvfs_rail_list);
+        }
+
+        mutex_unlock(&dvfs_lock);
+
+        return 0;
+};
+
+static int dvfs_solve_relationship(struct dvfs_relationship *rel)
+{
+        return rel->solve(rel->from, rel->to);
+}
+
+/* rail statistic - called during rail init, or under dfs_lock, or with
+   CPU0 only on-line, and interrupts disabled */
+static void dvfs_rail_stats_init(struct dvfs_rail *rail, int millivolts)
+{
+        rail->stats.last_update = ktime_get();
+        if (millivolts >= rail->min_millivolts) {
+                int i = 1 + (2 * (millivolts - rail->min_millivolts) *
+                        DVFS_RAIL_STATS_SCALE + DVFS_RAIL_STATS_BIN) /
+                        (2 * DVFS_RAIL_STATS_BIN);
+                rail->stats.last_index = min(i, DVFS_RAIL_STATS_TOP_BIN);
+        }
+
+        if (rail->max_millivolts >
+            rail->min_millivolts + DVFS_RAIL_STATS_RANGE)
+                pr_warn("tegra_dvfs: %s: stats above %d mV will be squashed\n",
+                        rail->reg_id,
+                        rail->min_millivolts + DVFS_RAIL_STATS_RANGE);
+}
+
+static void dvfs_rail_stats_update(
+        struct dvfs_rail *rail, int millivolts, ktime_t now)
+{
+        rail->stats.time_at_mv[rail->stats.last_index] = ktime_add(
+                rail->stats.time_at_mv[rail->stats.last_index], ktime_sub(
+                        now, rail->stats.last_update));
+        rail->stats.last_update = now;
+
+        if (rail->stats.off)
+                return;
+
+        if (millivolts >= rail->min_millivolts) {
+                int i = 1 + (2 * (millivolts - rail->min_millivolts) *
+                        DVFS_RAIL_STATS_SCALE + DVFS_RAIL_STATS_BIN) /
+                        (2 * DVFS_RAIL_STATS_BIN);
+                rail->stats.last_index = min(i, DVFS_RAIL_STATS_TOP_BIN);
+        } else if (millivolts == 0)
+                        rail->stats.last_index = 0;
+}
+
+static void dvfs_rail_stats_pause(struct dvfs_rail *rail,
+                                  ktime_t delta, bool on)
+{
+        int i = on ? rail->stats.last_index : 0;
+        rail->stats.time_at_mv[i] = ktime_add(rail->stats.time_at_mv[i], delta);
+}
+
+void tegra_dvfs_rail_off(struct dvfs_rail *rail, ktime_t now)
+{
+        if (rail) {
+                dvfs_rail_stats_update(rail, 0, now);
+                rail->stats.off = true;
+        }
+}
+
+void tegra_dvfs_rail_on(struct dvfs_rail *rail, ktime_t now)
+{
+        if (rail) {
+                rail->stats.off = false;
+                dvfs_rail_stats_update(rail, rail->millivolts, now);
+        }
+}
+
+void tegra_dvfs_rail_pause(struct dvfs_rail *rail, ktime_t delta, bool on)
+{
+        if (rail)
+                dvfs_rail_stats_pause(rail, delta, on);
+}
+
+/* Sets the voltage on a dvfs rail to a specific value, and updates any
+ * rails that depend on this rail. */
+static int dvfs_rail_set_voltage(struct dvfs_rail *rail, int millivolts)
+{
+        int ret = 0;
+        struct dvfs_relationship *rel;
+        int step = (millivolts > rail->millivolts) ? rail->step : -rail->step;
+        int i;
+        int steps;
+        bool jmp_to_zero;
+
+        if (!rail->reg) {
+                if (millivolts == rail->millivolts)
+                        return 0;
+                else
+                        return -EINVAL;
+        }
+
+        if (rail->disabled)
+                return 0;
+
+        rail->resolving_to = true;
+        jmp_to_zero = rail->jmp_to_zero &&
+                        ((millivolts == 0) || (rail->millivolts == 0));
+        steps = jmp_to_zero ? 1 :
+                DIV_ROUND_UP(abs(millivolts - rail->millivolts), rail->step);
+
+        for (i = 0; i < steps; i++) {
+                if (!jmp_to_zero &&
+                    (abs(millivolts - rail->millivolts) > rail->step))
+                        rail->new_millivolts = rail->millivolts + step;
+                else
+                        rail->new_millivolts = millivolts;
+
+                /* Before changing the voltage, tell each rail that depends
+                 * on this rail that the voltage will change.
+                 * This rail will be the "from" rail in the relationship,
+                 * the rail that depends on this rail will be the "to" rail.
+                 * from->millivolts will be the old voltage
+                 * from->new_millivolts will be the new voltage */
+                list_for_each_entry(rel, &rail->relationships_to, to_node) {
+                        ret = dvfs_rail_update(rel->to);
+                        if (ret)
+                                goto out;
+                }
+
+                if (!rail->disabled) {
+                        rail->updating = true;
+                        ret = regulator_set_voltage(rail->reg,
+                                rail->new_millivolts * 1000,
+                                rail->max_millivolts * 1000);
+                        rail->updating = false;
+                }
+                if (ret) {
+                        pr_err("Failed to set dvfs regulator %s\n", rail->reg_id);
+                        goto out;
+                }
+
+                rail->millivolts = rail->new_millivolts;
+                dvfs_rail_stats_update(rail, rail->millivolts, ktime_get());
+
+                /* After changing the voltage, tell each rail that depends
+                 * on this rail that the voltage has changed.
+                 * from->millivolts and from->new_millivolts will be the
+                 * new voltage */
+                list_for_each_entry(rel, &rail->relationships_to, to_node) {
+                        ret = dvfs_rail_update(rel->to);
+                        if (ret)
+                                goto out;
+                }
+        }
+
+        if (unlikely(rail->millivolts != millivolts)) {
+                pr_err("%s: rail didn't reach target %d in %d steps (%d)\n",
+                        __func__, millivolts, steps, rail->millivolts);
+                ret = -EINVAL;
+        }
+
+out:
+        rail->resolving_to = false;
+        return ret;
+}
+
+/* Determine the minimum valid voltage for a rail, taking into account
+ * the dvfs clocks and any rails that this rail depends on.  Calls
+ * dvfs_rail_set_voltage with the new voltage, which will call
+ * dvfs_rail_update on any rails that depend on this rail. */
+static int dvfs_rail_update(struct dvfs_rail *rail)
+{
+        int millivolts = 0;
+        struct dvfs *d;
+        struct dvfs_relationship *rel;
+        int ret = 0;
+        int steps;
+
+        /* if dvfs is suspended, return and handle it during resume */
+        if (rail->suspended)
+                return 0;
+
+        /* if regulators are not connected yet, return and handle it later */
+        if (!rail->reg)
+                return 0;
+
+        /* if rail update is entered while resolving circular dependencies,
+           abort recursion */
+        if (rail->resolving_to)
+                return 0;
+
+        /* Find the maximum voltage requested by any clock */
+        list_for_each_entry(d, &rail->dvfs, reg_node)
+                millivolts = max(d->cur_millivolts, millivolts);
+
+        /* retry update if limited by from-relationship to account for
+           circular dependencies */
+        steps = DIV_ROUND_UP(abs(millivolts - rail->millivolts), rail->step);
+        for (; steps >= 0; steps--) {
+                rail->new_millivolts = millivolts;
+
+                /* Check any rails that this rail depends on */
+                list_for_each_entry(rel, &rail->relationships_from, from_node)
+                        rail->new_millivolts = dvfs_solve_relationship(rel);
+
+                if (rail->new_millivolts == rail->millivolts)
+                        break;
+
+                ret = dvfs_rail_set_voltage(rail, rail->new_millivolts);
+        }
+
+        return ret;
+}
+
+static int dvfs_rail_connect_to_regulator(struct dvfs_rail *rail)
+{
+        struct regulator *reg;
+        int v;
+
+        if (!rail->reg) {
+                reg = regulator_get(NULL, rail->reg_id);
+                if (IS_ERR(reg)) {
+                        pr_err("tegra_dvfs: failed to connect %s rail\n",
+                               rail->reg_id);
+                        return -EINVAL;
+                }
+                rail->reg = reg;
+        }
+
+        v = regulator_get_voltage(rail->reg);
+        if (v < 0) {
+                pr_err("tegra_dvfs: failed initial get %s voltage\n",
+                       rail->reg_id);
+                return v;
+        }
+        rail->millivolts = v / 1000;
+        rail->new_millivolts = rail->millivolts;
+        dvfs_rail_stats_init(rail, rail->millivolts);
+        return 0;
+}
+
+static inline unsigned long *dvfs_get_freqs(struct dvfs *d)
+{
+        return (d->alt_freqs_state == ALT_FREQS_ENABLED) ?
+                &d->alt_freqs[0] : &d->freqs[0];
+}
+
+static int
+__tegra_dvfs_set_rate(struct dvfs *d, unsigned long rate)
+{
+        int i = 0;
+        int ret;
+        unsigned long *freqs = dvfs_get_freqs(d);
+
+        if (freqs == NULL || d->millivolts == NULL)
+                return -ENODEV;
+
+        if (rate > freqs[d->num_freqs - 1]) {
+                pr_warn("tegra_dvfs: rate %lu too high for dvfs on %s\n", rate,
+                        d->clk_name);
+                return -EINVAL;
+        }
+
+        if (rate == 0) {
+                d->cur_millivolts = 0;
+        } else {
+                while (i < d->num_freqs && rate > freqs[i])
+                        i++;
+
+                if ((d->max_millivolts) &&
+                    (d->millivolts[i] > d->max_millivolts)) {
+                        pr_warn("tegra_dvfs: voltage %d too high for dvfs on"
+                                " %s\n", d->millivolts[i], d->clk_name);
+                        return -EINVAL;
+                }
+                d->cur_millivolts = d->millivolts[i];
+        }
+
+        d->cur_rate = rate;
+
+        ret = dvfs_rail_update(d->dvfs_rail);
+        if (ret)
+                pr_err("Failed to set regulator %s for clock %s to %d mV\n",
+                        d->dvfs_rail->reg_id, d->clk_name, d->cur_millivolts);
+
+        return ret;
+}
+
+static inline int dvfs_alt_freqs_set(struct dvfs *d, bool enable)
+{
+        if (d->alt_freqs_state == ALT_FREQS_NOT_SUPPORTED)
+                return -ENOSYS;
+
+        d->alt_freqs_state = enable ? ALT_FREQS_ENABLED : ALT_FREQS_DISABLED;
+        return 0;
+}
+
+int tegra_dvfs_alt_freqs_set(struct dvfs *d, bool enable)
+{
+        int ret;
+        enum dvfs_alt_freqs old_state;
+
+        mutex_lock(&dvfs_lock);
+
+        old_state = d->alt_freqs_state;
+        ret = dvfs_alt_freqs_set(d, enable);
+        if (!ret && (old_state != d->alt_freqs_state))
+                ret = __tegra_dvfs_set_rate(d, d->cur_rate);
+
+        mutex_unlock(&dvfs_lock);
+        return ret;
+}
+
+int tegra_dvfs_predict_millivolts(struct clk *c, unsigned long rate)
+{
+        int i;
+
+        if (!rate || !c->dvfs)
+                return 0;
+
+        if (!c->dvfs->millivolts)
+                return -ENODEV;
+
+        /*
+         * Predicted voltage can not be used across the switch to alternative
+         * frequency limits. For now, just fail the call for clock that has
+         * alternative limits initialized.
+         */
+        if (c->dvfs->alt_freqs_state != ALT_FREQS_NOT_SUPPORTED)
+                return -ENOSYS;
+
+        for (i = 0; i < c->dvfs->num_freqs; i++) {
+                if (rate <= c->dvfs->freqs[i])
+                        break;
+        }
+
+        if (i == c->dvfs->num_freqs)
+                return -EINVAL;
+
+        return c->dvfs->millivolts[i];
+}
+
+int tegra_dvfs_set_rate(struct clk *c, unsigned long rate)
+{
+        int ret;
+
+        if (!c->dvfs)
+                return -EINVAL;
+
+        mutex_lock(&dvfs_lock);
+        ret = __tegra_dvfs_set_rate(c->dvfs, rate);
+        mutex_unlock(&dvfs_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL(tegra_dvfs_set_rate);
+
+/* May only be called during clock init, does not take any locks on clock c. */
+int __init tegra_enable_dvfs_on_clk(struct clk *c, struct dvfs *d)
+{
+        int i;
+
+        if (c->dvfs) {
+                pr_err("Error when enabling dvfs on %s for clock %s:\n",
+                        d->dvfs_rail->reg_id, c->name);
+                pr_err("DVFS already enabled for %s\n",
+                        c->dvfs->dvfs_rail->reg_id);
+                return -EINVAL;
+        }
+
+        for (i = 0; i < MAX_DVFS_FREQS; i++) {
+                if (d->millivolts[i] == 0)
+                        break;
+
+                d->freqs[i] *= d->freqs_mult;
+
+                /* If final frequencies are 0, pad with previous frequency */
+                if (d->freqs[i] == 0 && i > 1)
+                        d->freqs[i] = d->freqs[i - 1];
+        }
+        d->num_freqs = i;
+
+        if (d->auto_dvfs) {
+                c->auto_dvfs = true;
+                clk_set_cansleep(c);
+        }
+
+        c->dvfs = d;
+
+        mutex_lock(&dvfs_lock);
+        list_add_tail(&d->reg_node, &d->dvfs_rail->dvfs);
+        mutex_unlock(&dvfs_lock);
+
+        return 0;
+}
+
+static bool tegra_dvfs_all_rails_suspended(void)
+{
+        struct dvfs_rail *rail;
+        bool all_suspended = true;
+
+        list_for_each_entry(rail, &dvfs_rail_list, node)
+                if (!rail->suspended && !rail->disabled)
+                        all_suspended = false;
+
+        return all_suspended;
+}
+
+static bool tegra_dvfs_from_rails_suspended_or_solved(struct dvfs_rail *to)
+{
+        struct dvfs_relationship *rel;
+        bool all_suspended = true;
+
+        list_for_each_entry(rel, &to->relationships_from, from_node)
+                if (!rel->from->suspended && !rel->from->disabled &&
+                        !rel->solved_at_nominal)
+                        all_suspended = false;
+
+        return all_suspended;
+}
+
+static int tegra_dvfs_suspend_one(void)
+{
+        struct dvfs_rail *rail;
+        int ret;
+
+        list_for_each_entry(rail, &dvfs_rail_list, node) {
+                if (!rail->suspended && !rail->disabled &&
+                    tegra_dvfs_from_rails_suspended_or_solved(rail)) {
+                        ret = dvfs_rail_set_voltage(rail,
+                                rail->nominal_millivolts);
+                        if (ret)
+                                return ret;
+                        rail->suspended = true;
+                        return 0;
+                }
+        }
+
+        return -EINVAL;
+}
+
+static void tegra_dvfs_resume(void)
+{
+        struct dvfs_rail *rail;
+
+        mutex_lock(&dvfs_lock);
+
+        list_for_each_entry(rail, &dvfs_rail_list, node)
+                rail->suspended = false;
+
+        list_for_each_entry(rail, &dvfs_rail_list, node)
+                dvfs_rail_update(rail);
+
+        mutex_unlock(&dvfs_lock);
+}
+
+static int tegra_dvfs_suspend(void)
+{
+        int ret = 0;
+
+        mutex_lock(&dvfs_lock);
+
+        while (!tegra_dvfs_all_rails_suspended()) {
+                ret = tegra_dvfs_suspend_one();
+                if (ret)
+                        break;
+        }
+
+        mutex_unlock(&dvfs_lock);
+
+        if (ret)
+                tegra_dvfs_resume();
+
+        return ret;
+}
+
+static int tegra_dvfs_pm_notify(struct notifier_block *nb,
+                                unsigned long event, void *data)
+{
+        switch (event) {
+        case PM_SUSPEND_PREPARE:
+                if (tegra_dvfs_suspend())
+                        return NOTIFY_STOP;
+                break;
+        case PM_POST_SUSPEND:
+                tegra_dvfs_resume();
+                break;
+        }
+
+        return NOTIFY_OK;
+};
+
+static struct notifier_block tegra_dvfs_nb = {
+        .notifier_call = tegra_dvfs_pm_notify,
+};
+
+static int tegra_dvfs_reboot_notify(struct notifier_block *nb,
+                                unsigned long event, void *data)
+{
+        switch (event) {
+        case SYS_RESTART:
+        case SYS_HALT:
+        case SYS_POWER_OFF:
+                tegra_dvfs_suspend();
+                return NOTIFY_OK;
+        }
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block tegra_dvfs_reboot_nb = {
+        .notifier_call = tegra_dvfs_reboot_notify,
+};
+
+/* must be called with dvfs lock held */
+static void __tegra_dvfs_rail_disable(struct dvfs_rail *rail)
+{
+        int ret;
+
+        ret = dvfs_rail_set_voltage(rail, rail->nominal_millivolts);
+        if (ret)
+                pr_info("dvfs: failed to set regulator %s to disable "
+                        "voltage %d\n", rail->reg_id,
+                        rail->nominal_millivolts);
+        rail->disabled = true;
+}
+
+/* must be called with dvfs lock held */
+static void __tegra_dvfs_rail_enable(struct dvfs_rail *rail)
+{
+        rail->disabled = false;
+        dvfs_rail_update(rail);
+}
+
+void tegra_dvfs_rail_enable(struct dvfs_rail *rail)
+{
+        mutex_lock(&rail_disable_lock);
+
+        if (rail->disabled) {
+                mutex_lock(&dvfs_lock);
+                __tegra_dvfs_rail_enable(rail);
+                mutex_unlock(&dvfs_lock);
+
+                tegra_dvfs_rail_post_enable(rail);
+        }
+        mutex_unlock(&rail_disable_lock);
+
+}
+
+void tegra_dvfs_rail_disable(struct dvfs_rail *rail)
+{
+        mutex_lock(&rail_disable_lock);
+        if (rail->disabled)
+                goto out;
+
+        /* rail disable will set it to nominal voltage underneath clock
+           framework - need to re-configure clock rates that are not safe
+           at nominal (yes, unsafe at nominal is ugly, but possible). Rate
+           change must be done outside of dvfs lock. */
+        if (tegra_dvfs_rail_disable_prepare(rail)) {
+                pr_info("dvfs: failed to prepare regulator %s to disable\n",
+                        rail->reg_id);
+                goto out;
+        }
+
+        mutex_lock(&dvfs_lock);
+        __tegra_dvfs_rail_disable(rail);
+        mutex_unlock(&dvfs_lock);
+out:
+        mutex_unlock(&rail_disable_lock);
+}
+
+int tegra_dvfs_rail_disable_by_name(const char *reg_id)
+{
+        struct dvfs_rail *rail = tegra_dvfs_get_rail_by_name(reg_id);
+        if (!rail)
+                return -EINVAL;
+
+        tegra_dvfs_rail_disable(rail);
+        return 0;
+}
+
+struct dvfs_rail *tegra_dvfs_get_rail_by_name(const char *reg_id)
+{
+        struct dvfs_rail *rail;
+
+        mutex_lock(&dvfs_lock);
+        list_for_each_entry(rail, &dvfs_rail_list, node) {
+                if (!strcmp(reg_id, rail->reg_id)) {
+                        mutex_unlock(&dvfs_lock);
+                        return rail;
+                }
+        }
+        mutex_unlock(&dvfs_lock);
+        return NULL;
+}
+
+bool tegra_dvfs_rail_updating(struct clk *clk)
+{
+        return (!clk ? false :
+                (!clk->dvfs ? false :
+                 (!clk->dvfs->dvfs_rail ? false :
+                  (clk->dvfs->dvfs_rail->updating))));
+}
+
+/*
+ * Iterate through all the dvfs regulators, finding the regulator exported
+ * by the regulator api for each one.  Must be called in late init, after
+ * all the regulator api's regulators are initialized.
+ */
+int __init tegra_dvfs_late_init(void)
+{
+        bool connected = true;
+        struct dvfs_rail *rail;
+
+        mutex_lock(&dvfs_lock);
+
+        list_for_each_entry(rail, &dvfs_rail_list, node)
+                if (dvfs_rail_connect_to_regulator(rail))
+                        connected = false;
+
+        list_for_each_entry(rail, &dvfs_rail_list, node)
+                if (connected)
+                        dvfs_rail_update(rail);
+                else
+                        __tegra_dvfs_rail_disable(rail);
+
+        mutex_unlock(&dvfs_lock);
+
+        register_pm_notifier(&tegra_dvfs_nb);
+        register_reboot_notifier(&tegra_dvfs_reboot_nb);
+
+        return 0;
+}
+late_initcall(tegra_dvfs_late_init);
+
+#ifdef CONFIG_DEBUG_FS
+static int dvfs_tree_sort_cmp(void *p, struct list_head *a, struct list_head *b)
+{
+        struct dvfs *da = list_entry(a, struct dvfs, reg_node);
+        struct dvfs *db = list_entry(b, struct dvfs, reg_node);
+        int ret;
+
+        ret = strcmp(da->dvfs_rail->reg_id, db->dvfs_rail->reg_id);
+        if (ret != 0)
+                return ret;
+
+        if (da->cur_millivolts < db->cur_millivolts)
+                return 1;
+        if (da->cur_millivolts > db->cur_millivolts)
+                return -1;
+
+        return strcmp(da->clk_name, db->clk_name);
+}
+
+static int dvfs_tree_show(struct seq_file *s, void *data)
+{
+        struct dvfs *d;
+        struct dvfs_rail *rail;
+        struct dvfs_relationship *rel;
+
+        seq_printf(s, "   clock      rate       mV\n");
+        seq_printf(s, "--------------------------------\n");
+
+        mutex_lock(&dvfs_lock);
+
+        list_for_each_entry(rail, &dvfs_rail_list, node) {
+                seq_printf(s, "%s %d mV%s:\n", rail->reg_id,
+                        rail->millivolts, rail->disabled ? " disabled" : "");
+                list_for_each_entry(rel, &rail->relationships_from, from_node) {
+                        seq_printf(s, "   %-10s %-7d mV %-4d mV\n",
+                                rel->from->reg_id,
+                                rel->from->millivolts,
+                                dvfs_solve_relationship(rel));
+                }
+
+                list_sort(NULL, &rail->dvfs, dvfs_tree_sort_cmp);
+
+                list_for_each_entry(d, &rail->dvfs, reg_node) {
+                        seq_printf(s, "   %-10s %-10lu %-4d mV\n", d->clk_name,
+                                d->cur_rate, d->cur_millivolts);
+                }
+        }
+
+        mutex_unlock(&dvfs_lock);
+
+        return 0;
+}
+
+static int dvfs_tree_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, dvfs_tree_show, inode->i_private);
+}
+
+static const struct file_operations dvfs_tree_fops = {
+        .open           = dvfs_tree_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+static int rail_stats_show(struct seq_file *s, void *data)
+{
+        int i;
+        struct dvfs_rail *rail;
+
+        seq_printf(s, "%-12s %-10s (bin: %d.%dmV)\n", "millivolts", "time",
+                   DVFS_RAIL_STATS_BIN / DVFS_RAIL_STATS_SCALE,
+                   ((DVFS_RAIL_STATS_BIN * 100) / DVFS_RAIL_STATS_SCALE) % 100);
+
+        mutex_lock(&dvfs_lock);
+
+        list_for_each_entry(rail, &dvfs_rail_list, node) {
+                seq_printf(s, "%s\n", rail->reg_id);
+                dvfs_rail_stats_update(rail, -1, ktime_get());
+
+                seq_printf(s, "%-12d %-10llu\n", 0,
+                        cputime64_to_clock_t(msecs_to_jiffies(
+                                ktime_to_ms(rail->stats.time_at_mv[0]))));
+
+                for (i = 1; i <= DVFS_RAIL_STATS_TOP_BIN; i++) {
+                        ktime_t ktime_zero = ktime_set(0, 0);
+                        if (ktime_equal(rail->stats.time_at_mv[i], ktime_zero))
+                                continue;
+                        seq_printf(s, "%-12d %-10llu\n",
+                                   rail->min_millivolts + (i - 1) *
+                                   DVFS_RAIL_STATS_BIN / DVFS_RAIL_STATS_SCALE,
+                                cputime64_to_clock_t(msecs_to_jiffies(
+                                        ktime_to_ms(rail->stats.time_at_mv[i])))
+                        );
+                }
+        }
+        mutex_unlock(&dvfs_lock);
+        return 0;
+}
+
+static int rail_stats_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, rail_stats_show, inode->i_private);
+}
+
+static const struct file_operations rail_stats_fops = {
+        .open           = rail_stats_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
+};
+
+int __init dvfs_debugfs_init(struct dentry *clk_debugfs_root)
+{
+        struct dentry *d;
+
+        d = debugfs_create_file("dvfs", S_IRUGO, clk_debugfs_root, NULL,
+                &dvfs_tree_fops);
+        if (!d)
+                return -ENOMEM;
+
+        d = debugfs_create_file("rails", S_IRUGO, clk_debugfs_root, NULL,
+                &rail_stats_fops);
+        if (!d)
+                return -ENOMEM;
+
+        return 0;
+}
+
+#endif