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222 lines
5.5 KiB
222 lines
5.5 KiB
/* |
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* CPU Frequency Scaling for Loongson 1 SoC |
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* |
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* Copyright (C) 2014-2016 Zhang, Keguang <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public |
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* License version 2. This program is licensed "as is" without any |
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* warranty of any kind, whether express or implied. |
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*/ |
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#include <linux/clk.h> |
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#include <linux/clk-provider.h> |
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#include <linux/cpu.h> |
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#include <linux/cpufreq.h> |
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#include <linux/delay.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <cpufreq.h> |
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#include <loongson1.h> |
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struct ls1x_cpufreq { |
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struct device *dev; |
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struct clk *clk; /* CPU clk */ |
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struct clk *mux_clk; /* MUX of CPU clk */ |
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struct clk *pll_clk; /* PLL clk */ |
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struct clk *osc_clk; /* OSC clk */ |
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unsigned int max_freq; |
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unsigned int min_freq; |
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}; |
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static struct ls1x_cpufreq *cpufreq; |
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static int ls1x_cpufreq_notifier(struct notifier_block *nb, |
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unsigned long val, void *data) |
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{ |
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if (val == CPUFREQ_POSTCHANGE) |
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current_cpu_data.udelay_val = loops_per_jiffy; |
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return NOTIFY_OK; |
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} |
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static struct notifier_block ls1x_cpufreq_notifier_block = { |
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.notifier_call = ls1x_cpufreq_notifier |
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}; |
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static int ls1x_cpufreq_target(struct cpufreq_policy *policy, |
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unsigned int index) |
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{ |
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struct device *cpu_dev = get_cpu_device(policy->cpu); |
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unsigned int old_freq, new_freq; |
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old_freq = policy->cur; |
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new_freq = policy->freq_table[index].frequency; |
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/* |
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* The procedure of reconfiguring CPU clk is as below. |
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* |
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* - Reparent CPU clk to OSC clk |
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* - Reset CPU clock (very important) |
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* - Reconfigure CPU DIV |
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* - Reparent CPU clk back to CPU DIV clk |
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*/ |
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clk_set_parent(policy->clk, cpufreq->osc_clk); |
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__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU, |
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LS1X_CLK_PLL_DIV); |
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__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU), |
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LS1X_CLK_PLL_DIV); |
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clk_set_rate(cpufreq->mux_clk, new_freq * 1000); |
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clk_set_parent(policy->clk, cpufreq->mux_clk); |
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dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq); |
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return 0; |
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} |
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static int ls1x_cpufreq_init(struct cpufreq_policy *policy) |
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{ |
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struct device *cpu_dev = get_cpu_device(policy->cpu); |
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struct cpufreq_frequency_table *freq_tbl; |
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unsigned int pll_freq, freq; |
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int steps, i; |
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pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000; |
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steps = 1 << DIV_CPU_WIDTH; |
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freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL); |
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if (!freq_tbl) |
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return -ENOMEM; |
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for (i = 0; i < (steps - 1); i++) { |
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freq = pll_freq / (i + 1); |
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if ((freq < cpufreq->min_freq) || (freq > cpufreq->max_freq)) |
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freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID; |
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else |
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freq_tbl[i].frequency = freq; |
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dev_dbg(cpu_dev, |
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"cpufreq table: index %d: frequency %d\n", i, |
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freq_tbl[i].frequency); |
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} |
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freq_tbl[i].frequency = CPUFREQ_TABLE_END; |
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policy->clk = cpufreq->clk; |
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cpufreq_generic_init(policy, freq_tbl, 0); |
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return 0; |
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} |
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static int ls1x_cpufreq_exit(struct cpufreq_policy *policy) |
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{ |
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kfree(policy->freq_table); |
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return 0; |
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} |
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static struct cpufreq_driver ls1x_cpufreq_driver = { |
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.name = "cpufreq-ls1x", |
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.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = ls1x_cpufreq_target, |
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.get = cpufreq_generic_get, |
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.init = ls1x_cpufreq_init, |
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.exit = ls1x_cpufreq_exit, |
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.attr = cpufreq_generic_attr, |
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}; |
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static int ls1x_cpufreq_remove(struct platform_device *pdev) |
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{ |
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cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block, |
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CPUFREQ_TRANSITION_NOTIFIER); |
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cpufreq_unregister_driver(&ls1x_cpufreq_driver); |
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return 0; |
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} |
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static int ls1x_cpufreq_probe(struct platform_device *pdev) |
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{ |
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struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev); |
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struct clk *clk; |
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int ret; |
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if (!pdata || !pdata->clk_name || !pdata->osc_clk_name) { |
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dev_err(&pdev->dev, "platform data missing\n"); |
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return -EINVAL; |
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} |
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cpufreq = |
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devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL); |
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if (!cpufreq) |
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return -ENOMEM; |
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cpufreq->dev = &pdev->dev; |
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clk = devm_clk_get(&pdev->dev, pdata->clk_name); |
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if (IS_ERR(clk)) { |
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dev_err(&pdev->dev, "unable to get %s clock\n", |
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pdata->clk_name); |
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return PTR_ERR(clk); |
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} |
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cpufreq->clk = clk; |
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clk = clk_get_parent(clk); |
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if (IS_ERR(clk)) { |
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dev_err(&pdev->dev, "unable to get parent of %s clock\n", |
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__clk_get_name(cpufreq->clk)); |
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return PTR_ERR(clk); |
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} |
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cpufreq->mux_clk = clk; |
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clk = clk_get_parent(clk); |
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if (IS_ERR(clk)) { |
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dev_err(&pdev->dev, "unable to get parent of %s clock\n", |
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__clk_get_name(cpufreq->mux_clk)); |
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return PTR_ERR(clk); |
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} |
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cpufreq->pll_clk = clk; |
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clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name); |
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if (IS_ERR(clk)) { |
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dev_err(&pdev->dev, "unable to get %s clock\n", |
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pdata->osc_clk_name); |
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return PTR_ERR(clk); |
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} |
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cpufreq->osc_clk = clk; |
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cpufreq->max_freq = pdata->max_freq; |
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cpufreq->min_freq = pdata->min_freq; |
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ret = cpufreq_register_driver(&ls1x_cpufreq_driver); |
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if (ret) { |
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dev_err(&pdev->dev, |
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"failed to register CPUFreq driver: %d\n", ret); |
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return ret; |
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} |
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ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block, |
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CPUFREQ_TRANSITION_NOTIFIER); |
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if (ret) { |
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dev_err(&pdev->dev, |
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"failed to register CPUFreq notifier: %d\n",ret); |
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cpufreq_unregister_driver(&ls1x_cpufreq_driver); |
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} |
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return ret; |
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} |
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static struct platform_driver ls1x_cpufreq_platdrv = { |
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.probe = ls1x_cpufreq_probe, |
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.remove = ls1x_cpufreq_remove, |
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.driver = { |
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.name = "ls1x-cpufreq", |
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}, |
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}; |
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module_platform_driver(ls1x_cpufreq_platdrv); |
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MODULE_ALIAS("platform:ls1x-cpufreq"); |
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MODULE_AUTHOR("Kelvin Cheung <[email protected]>"); |
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MODULE_DESCRIPTION("Loongson1 CPUFreq driver"); |
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MODULE_LICENSE("GPL");
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