246 lines
6.7 KiB
Diff
246 lines
6.7 KiB
Diff
From 5cf343c60d7557aefb468603065cac5062f11b8d Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Fri, 30 May 2014 16:36:11 -0700
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Subject: [PATCH 172/182] cpufreq: Add a cpufreq-krait based on cpufreq-cpu0
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Krait processors have individual clocks for each CPU that can
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scale independently from one another. cpufreq-cpu0 is fairly
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close to this, but assumes that there is only one clock for all
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CPUs. Add a driver to support the Krait configuration.
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TODO: Merge into cpufreq-cpu0? Or make generic?
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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---
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drivers/cpufreq/Kconfig | 13 +++
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drivers/cpufreq/Makefile | 1 +
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drivers/cpufreq/cpufreq-krait.c | 190 +++++++++++++++++++++++++++++++++++++++
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3 files changed, 204 insertions(+)
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create mode 100644 drivers/cpufreq/cpufreq-krait.c
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--- a/drivers/cpufreq/Kconfig
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+++ b/drivers/cpufreq/Kconfig
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@@ -194,6 +194,19 @@ config GENERIC_CPUFREQ_CPU0
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If in doubt, say N.
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+config GENERIC_CPUFREQ_KRAIT
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+ tristate "Krait cpufreq driver"
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+ depends on HAVE_CLK && OF
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+ # if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y:
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+ depends on !CPU_THERMAL || THERMAL
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+ select PM_OPP
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+ help
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+ This adds a generic cpufreq driver for CPU0 frequency management.
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+ It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
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+ systems which share clock and voltage across all CPUs.
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+
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+ If in doubt, say N.
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+
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menu "x86 CPU frequency scaling drivers"
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depends on X86
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source "drivers/cpufreq/Kconfig.x86"
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--- a/drivers/cpufreq/Makefile
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+++ b/drivers/cpufreq/Makefile
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@@ -12,6 +12,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)
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obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o
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obj-$(CONFIG_GENERIC_CPUFREQ_CPU0) += cpufreq-cpu0.o
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+obj-$(CONFIG_GENERIC_CPUFREQ_KRAIT) += cpufreq-krait.o
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##################################################################################
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# x86 drivers.
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--- /dev/null
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+++ b/drivers/cpufreq/cpufreq-krait.c
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@@ -0,0 +1,190 @@
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+/*
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+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
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+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
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+ *
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+ * The OPP code in function krait_set_target() is reused from
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+ * drivers/cpufreq/omap-cpufreq.c
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/clk.h>
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+#include <linux/cpu.h>
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+#include <linux/cpu_cooling.h>
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+#include <linux/cpufreq.h>
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+#include <linux/cpumask.h>
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+#include <linux/err.h>
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+#include <linux/module.h>
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+#include <linux/of.h>
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+#include <linux/pm_opp.h>
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+#include <linux/platform_device.h>
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+#include <linux/slab.h>
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+#include <linux/thermal.h>
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+
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+static unsigned int transition_latency;
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+
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+static struct device *cpu_dev;
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+static DEFINE_PER_CPU(struct clk *, krait_cpu_clks);
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+static struct cpufreq_frequency_table *freq_table;
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+static struct thermal_cooling_device *cdev;
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+
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+static int krait_set_target(struct cpufreq_policy *policy, unsigned int index)
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+{
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+ unsigned long volt = 0, volt_old = 0;
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+ unsigned int old_freq, new_freq;
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+ long freq_Hz, freq_exact;
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+ int ret;
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+ struct clk *cpu_clk;
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+
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+ cpu_clk = per_cpu(krait_cpu_clks, policy->cpu);
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+
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+ freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
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+ if (freq_Hz <= 0)
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+ freq_Hz = freq_table[index].frequency * 1000;
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+
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+ freq_exact = freq_Hz;
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+ new_freq = freq_Hz / 1000;
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+ old_freq = clk_get_rate(cpu_clk) / 1000;
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+
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+ pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
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+ old_freq / 1000, volt_old ? volt_old / 1000 : -1,
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+ new_freq / 1000, volt ? volt / 1000 : -1);
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+
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+ ret = clk_set_rate(cpu_clk, freq_exact);
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+ if (ret)
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+ pr_err("failed to set clock rate: %d\n", ret);
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+
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+ return ret;
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+}
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+
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+static int krait_cpufreq_init(struct cpufreq_policy *policy)
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+{
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+ int ret;
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+
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+ policy->clk = per_cpu(krait_cpu_clks, policy->cpu);
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+
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+ ret = cpufreq_table_validate_and_show(policy, freq_table);
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+ if (ret) {
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+ pr_err("%s: invalid frequency table: %d\n", __func__, ret);
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+ return ret;
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+ }
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+
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+ policy->cpuinfo.transition_latency = transition_latency;
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+
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+ return 0;
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+}
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+
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+static struct cpufreq_driver krait_cpufreq_driver = {
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+ .flags = CPUFREQ_STICKY,
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+ .verify = cpufreq_generic_frequency_table_verify,
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+ .target_index = krait_set_target,
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+ .get = cpufreq_generic_get,
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+ .init = krait_cpufreq_init,
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+ .name = "generic_krait",
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+ .attr = cpufreq_generic_attr,
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+};
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+
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+static int krait_cpufreq_probe(struct platform_device *pdev)
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+{
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+ struct device_node *np;
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+ int ret;
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+ unsigned int cpu;
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+ struct device *dev;
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+ struct clk *clk;
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+
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+ cpu_dev = get_cpu_device(0);
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+ if (!cpu_dev) {
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+ pr_err("failed to get krait device\n");
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+ return -ENODEV;
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+ }
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+
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+ np = of_node_get(cpu_dev->of_node);
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+ if (!np) {
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+ pr_err("failed to find krait node\n");
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+ return -ENOENT;
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+ }
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+
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+ for_each_possible_cpu(cpu) {
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+ dev = get_cpu_device(cpu);
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+ if (!dev) {
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+ pr_err("failed to get krait device\n");
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+ ret = -ENOENT;
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+ goto out_put_node;
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+ }
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+ per_cpu(krait_cpu_clks, cpu) = clk = devm_clk_get(dev, NULL);
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+ if (IS_ERR(clk)) {
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+ ret = PTR_ERR(clk);
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+ goto out_put_node;
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+ }
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+ }
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+
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+ ret = of_init_opp_table(cpu_dev);
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+ if (ret) {
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+ pr_err("failed to init OPP table: %d\n", ret);
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+ goto out_put_node;
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+ }
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+
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+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
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+ if (ret) {
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+ pr_err("failed to init cpufreq table: %d\n", ret);
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+ goto out_put_node;
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+ }
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+
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+ if (of_property_read_u32(np, "clock-latency", &transition_latency))
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+ transition_latency = CPUFREQ_ETERNAL;
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+
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+ ret = cpufreq_register_driver(&krait_cpufreq_driver);
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+ if (ret) {
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+ pr_err("failed register driver: %d\n", ret);
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+ goto out_free_table;
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+ }
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+ of_node_put(np);
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+
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+ /*
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+ * For now, just loading the cooling device;
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+ * thermal DT code takes care of matching them.
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+ */
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+ for_each_possible_cpu(cpu) {
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+ dev = get_cpu_device(cpu);
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+ np = of_node_get(dev->of_node);
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+ if (of_find_property(np, "#cooling-cells", NULL)) {
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+ cdev = of_cpufreq_cooling_register(np, cpumask_of(cpu));
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+ if (IS_ERR(cdev))
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+ pr_err("running cpufreq without cooling device: %ld\n",
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+ PTR_ERR(cdev));
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+ }
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+ of_node_put(np);
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+ }
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+
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+ return 0;
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+
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+out_free_table:
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+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
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+out_put_node:
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+ of_node_put(np);
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+ return ret;
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+}
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+
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+static int krait_cpufreq_remove(struct platform_device *pdev)
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+{
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+ cpufreq_cooling_unregister(cdev);
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+ cpufreq_unregister_driver(&krait_cpufreq_driver);
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+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
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+
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+ return 0;
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+}
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+
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+static struct platform_driver krait_cpufreq_platdrv = {
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+ .driver = {
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+ .name = "cpufreq-krait",
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+ .owner = THIS_MODULE,
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+ },
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+ .probe = krait_cpufreq_probe,
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+ .remove = krait_cpufreq_remove,
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+};
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+module_platform_driver(krait_cpufreq_platdrv);
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+
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+MODULE_DESCRIPTION("Krait CPUfreq driver");
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+MODULE_LICENSE("GPL v2");
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