![Viresh Kumar](/assets/img/avatar_default.png)
Most of the CPUFreq drivers do similar things in .exit() and .verify() routines and .attr. So its better if we have generic routines for them which can be used by cpufreq drivers then. This patch uses these generic routines in the kirkwood driver. Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
231 lines
5.8 KiB
C
231 lines
5.8 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_device.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_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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/* 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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return cpufreq_table_validate_and_show(policy, kirkwood_freq_table);
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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 = cpufreq_generic_frequency_table_verify,
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.target = kirkwood_cpufreq_target,
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.init = kirkwood_cpufreq_cpu_init,
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.exit = cpufreq_generic_exit,
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.name = "kirkwood-cpufreq",
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.attr = cpufreq_generic_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_cpu_device_node_get(0);
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if (!np) {
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dev_err(&pdev->dev, "failed to get cpu device node\n");
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return -ENODEV;
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}
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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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