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![Viresh Kumar](/assets/img/avatar_default.png)
The "index" field of struct cpufreq_frequency_table was never an index and isn't used at all by the cpufreq core. It only is useful for cpufreq drivers for their internal purposes. Many people nowadays blindly set it in ascending order with the assumption that the core will use it, which is a mistake. Rename it to "driver_data" as that's what its purpose is. All of its users are updated accordingly. [rjw: Changelog] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
253 lines
6.2 KiB
C
253 lines
6.2 KiB
C
/*
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* kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
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*
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* Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/clk-provider.h>
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#include <linux/cpufreq.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <asm/proc-fns.h>
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#define CPU_SW_INT_BLK BIT(28)
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static struct priv
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{
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struct clk *cpu_clk;
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struct clk *ddr_clk;
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struct clk *powersave_clk;
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struct device *dev;
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void __iomem *base;
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} priv;
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#define STATE_CPU_FREQ 0x01
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#define STATE_DDR_FREQ 0x02
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/*
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* Kirkwood can swap the clock to the CPU between two clocks:
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*
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* - cpu clk
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* - ddr clk
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*
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* The frequencies are set at runtime before registering this *
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* table.
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*/
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static struct cpufreq_frequency_table kirkwood_freq_table[] = {
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{STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */
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{STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */
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{0, CPUFREQ_TABLE_END},
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};
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static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
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{
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if (__clk_is_enabled(priv.powersave_clk))
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return kirkwood_freq_table[1].frequency;
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return kirkwood_freq_table[0].frequency;
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}
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static void kirkwood_cpufreq_set_cpu_state(struct cpufreq_policy *policy,
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unsigned int index)
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{
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struct cpufreq_freqs freqs;
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unsigned int state = kirkwood_freq_table[index].driver_data;
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unsigned long reg;
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freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
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freqs.new = kirkwood_freq_table[index].frequency;
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n",
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kirkwood_freq_table[index].frequency);
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dev_dbg(priv.dev, "old frequency was %i KHz\n",
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kirkwood_cpufreq_get_cpu_frequency(0));
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if (freqs.old != freqs.new) {
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local_irq_disable();
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/* Disable interrupts to the CPU */
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reg = readl_relaxed(priv.base);
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reg |= CPU_SW_INT_BLK;
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writel_relaxed(reg, priv.base);
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switch (state) {
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case STATE_CPU_FREQ:
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clk_disable(priv.powersave_clk);
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break;
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case STATE_DDR_FREQ:
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clk_enable(priv.powersave_clk);
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break;
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}
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/* Wait-for-Interrupt, while the hardware changes frequency */
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cpu_do_idle();
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/* Enable interrupts to the CPU */
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reg = readl_relaxed(priv.base);
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reg &= ~CPU_SW_INT_BLK;
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writel_relaxed(reg, priv.base);
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local_irq_enable();
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}
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cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
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};
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static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, kirkwood_freq_table);
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}
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static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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unsigned int index = 0;
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if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
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target_freq, relation, &index))
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return -EINVAL;
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kirkwood_cpufreq_set_cpu_state(policy, index);
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return 0;
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}
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/* Module init and exit code */
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static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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int result;
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/* cpuinfo and default policy values */
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policy->cpuinfo.transition_latency = 5000; /* 5uS */
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policy->cur = kirkwood_cpufreq_get_cpu_frequency(0);
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result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table);
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if (result)
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return result;
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cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu);
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return 0;
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}
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static int kirkwood_cpufreq_cpu_exit(struct cpufreq_policy *policy)
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{
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cpufreq_frequency_table_put_attr(policy->cpu);
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return 0;
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}
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static struct freq_attr *kirkwood_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static struct cpufreq_driver kirkwood_cpufreq_driver = {
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.get = kirkwood_cpufreq_get_cpu_frequency,
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.verify = kirkwood_cpufreq_verify,
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.target = kirkwood_cpufreq_target,
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.init = kirkwood_cpufreq_cpu_init,
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.exit = kirkwood_cpufreq_cpu_exit,
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.name = "kirkwood-cpufreq",
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.owner = THIS_MODULE,
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.attr = kirkwood_cpufreq_attr,
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};
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static int kirkwood_cpufreq_probe(struct platform_device *pdev)
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{
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struct device_node *np;
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struct resource *res;
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int err;
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priv.dev = &pdev->dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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priv.base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(priv.base))
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return PTR_ERR(priv.base);
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np = of_find_node_by_path("/cpus/cpu@0");
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if (!np)
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return -ENODEV;
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priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
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if (IS_ERR(priv.cpu_clk)) {
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dev_err(priv.dev, "Unable to get cpuclk");
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return PTR_ERR(priv.cpu_clk);
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}
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clk_prepare_enable(priv.cpu_clk);
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kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
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priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
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if (IS_ERR(priv.ddr_clk)) {
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dev_err(priv.dev, "Unable to get ddrclk");
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err = PTR_ERR(priv.ddr_clk);
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goto out_cpu;
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}
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clk_prepare_enable(priv.ddr_clk);
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kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
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priv.powersave_clk = of_clk_get_by_name(np, "powersave");
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if (IS_ERR(priv.powersave_clk)) {
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dev_err(priv.dev, "Unable to get powersave");
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err = PTR_ERR(priv.powersave_clk);
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goto out_ddr;
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}
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clk_prepare(priv.powersave_clk);
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of_node_put(np);
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np = NULL;
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err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
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if (!err)
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return 0;
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dev_err(priv.dev, "Failed to register cpufreq driver");
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clk_disable_unprepare(priv.powersave_clk);
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out_ddr:
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clk_disable_unprepare(priv.ddr_clk);
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out_cpu:
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clk_disable_unprepare(priv.cpu_clk);
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of_node_put(np);
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return err;
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}
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static int kirkwood_cpufreq_remove(struct platform_device *pdev)
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{
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cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
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clk_disable_unprepare(priv.powersave_clk);
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clk_disable_unprepare(priv.ddr_clk);
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clk_disable_unprepare(priv.cpu_clk);
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return 0;
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}
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static struct platform_driver kirkwood_cpufreq_platform_driver = {
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.probe = kirkwood_cpufreq_probe,
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.remove = kirkwood_cpufreq_remove,
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.driver = {
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.name = "kirkwood-cpufreq",
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(kirkwood_cpufreq_platform_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
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MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
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MODULE_ALIAS("platform:kirkwood-cpufreq");
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