138 lines
3 KiB
C
138 lines
3 KiB
C
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/*
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* Copyright 2008 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/cpufreq.h>
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#include <asm/delay.h>
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#include <asm/dpmc.h>
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#define DRIVER_NAME "bfin dpmc"
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#define dprintk(msg...) \
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cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, DRIVER_NAME, msg)
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struct bfin_dpmc_platform_data *pdata;
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/**
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* bfin_set_vlev - Update VLEV field in VR_CTL Reg.
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* Avoid BYPASS sequence
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*/
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static void bfin_set_vlev(unsigned int vlev)
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{
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unsigned pll_lcnt;
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pll_lcnt = bfin_read_PLL_LOCKCNT();
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bfin_write_PLL_LOCKCNT(1);
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bfin_write_VR_CTL((bfin_read_VR_CTL() & ~VLEV) | vlev);
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bfin_write_PLL_LOCKCNT(pll_lcnt);
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}
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/**
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* bfin_get_vlev - Get CPU specific VLEV from platform device data
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*/
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static unsigned int bfin_get_vlev(unsigned int freq)
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{
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int i;
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if (!pdata)
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goto err_out;
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freq >>= 16;
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for (i = 0; i < pdata->tabsize; i++)
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if (freq <= (pdata->tuple_tab[i] & 0xFFFF))
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return pdata->tuple_tab[i] >> 16;
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err_out:
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printk(KERN_WARNING "DPMC: No suitable CCLK VDDINT voltage pair found\n");
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return VLEV_120;
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}
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#ifdef CONFIG_CPU_FREQ
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static int
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vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
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{
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struct cpufreq_freqs *freq = data;
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if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) {
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bfin_set_vlev(bfin_get_vlev(freq->new));
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udelay(pdata->vr_settling_time); /* Wait until Volatge settled */
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} else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)
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bfin_set_vlev(bfin_get_vlev(freq->new));
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return 0;
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}
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static struct notifier_block vreg_cpufreq_notifier_block = {
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.notifier_call = vreg_cpufreq_notifier
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};
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#endif /* CONFIG_CPU_FREQ */
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/**
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* bfin_dpmc_probe -
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*
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*/
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static int __devinit bfin_dpmc_probe(struct platform_device *pdev)
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{
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if (pdev->dev.platform_data)
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pdata = pdev->dev.platform_data;
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else
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return -EINVAL;
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return cpufreq_register_notifier(&vreg_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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/**
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* bfin_dpmc_remove -
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*/
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static int __devexit bfin_dpmc_remove(struct platform_device *pdev)
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{
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pdata = NULL;
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return cpufreq_unregister_notifier(&vreg_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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}
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struct platform_driver bfin_dpmc_device_driver = {
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.probe = bfin_dpmc_probe,
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.remove = __devexit_p(bfin_dpmc_remove),
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.driver = {
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.name = DRIVER_NAME,
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}
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};
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/**
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* bfin_dpmc_init - Init driver
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*/
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static int __init bfin_dpmc_init(void)
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{
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return platform_driver_register(&bfin_dpmc_device_driver);
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}
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module_init(bfin_dpmc_init);
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/**
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* bfin_dpmc_exit - break down driver
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*/
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static void __exit bfin_dpmc_exit(void)
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{
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platform_driver_unregister(&bfin_dpmc_device_driver);
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}
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module_exit(bfin_dpmc_exit);
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MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
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MODULE_DESCRIPTION("cpu power management driver for Blackfin");
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MODULE_LICENSE("GPL");
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