| Michael Hennerich | 14b0320 | 2008-05-07 11:41:26 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2008 Analog Devices Inc. |
| 3 | * |
| 4 | * Licensed under the GPL-2 or later. |
| 5 | */ |
| 6 | |
| 7 | #include <linux/cdev.h> |
| 8 | #include <linux/device.h> |
| 9 | #include <linux/errno.h> |
| 10 | #include <linux/fs.h> |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/platform_device.h> |
| 14 | #include <linux/types.h> |
| 15 | #include <linux/cpufreq.h> |
| 16 | |
| 17 | #include <asm/delay.h> |
| 18 | #include <asm/dpmc.h> |
| 19 | |
| 20 | #define DRIVER_NAME "bfin dpmc" |
| 21 | |
| 22 | #define dprintk(msg...) \ |
| 23 | cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, DRIVER_NAME, msg) |
| 24 | |
| 25 | struct bfin_dpmc_platform_data *pdata; |
| 26 | |
| 27 | /** |
| 28 | * bfin_set_vlev - Update VLEV field in VR_CTL Reg. |
| 29 | * Avoid BYPASS sequence |
| 30 | */ |
| 31 | static void bfin_set_vlev(unsigned int vlev) |
| 32 | { |
| 33 | unsigned pll_lcnt; |
| 34 | |
| 35 | pll_lcnt = bfin_read_PLL_LOCKCNT(); |
| 36 | |
| 37 | bfin_write_PLL_LOCKCNT(1); |
| 38 | bfin_write_VR_CTL((bfin_read_VR_CTL() & ~VLEV) | vlev); |
| 39 | bfin_write_PLL_LOCKCNT(pll_lcnt); |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * bfin_get_vlev - Get CPU specific VLEV from platform device data |
| 44 | */ |
| 45 | static unsigned int bfin_get_vlev(unsigned int freq) |
| 46 | { |
| 47 | int i; |
| 48 | |
| 49 | if (!pdata) |
| 50 | goto err_out; |
| 51 | |
| 52 | freq >>= 16; |
| 53 | |
| 54 | for (i = 0; i < pdata->tabsize; i++) |
| 55 | if (freq <= (pdata->tuple_tab[i] & 0xFFFF)) |
| 56 | return pdata->tuple_tab[i] >> 16; |
| 57 | |
| 58 | err_out: |
| 59 | printk(KERN_WARNING "DPMC: No suitable CCLK VDDINT voltage pair found\n"); |
| 60 | return VLEV_120; |
| 61 | } |
| 62 | |
| 63 | #ifdef CONFIG_CPU_FREQ |
| 64 | static int |
| 65 | vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data) |
| 66 | { |
| 67 | struct cpufreq_freqs *freq = data; |
| 68 | |
| 69 | if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) { |
| 70 | bfin_set_vlev(bfin_get_vlev(freq->new)); |
| 71 | udelay(pdata->vr_settling_time); /* Wait until Volatge settled */ |
| 72 | |
| 73 | } else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) |
| 74 | bfin_set_vlev(bfin_get_vlev(freq->new)); |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static struct notifier_block vreg_cpufreq_notifier_block = { |
| 80 | .notifier_call = vreg_cpufreq_notifier |
| 81 | }; |
| 82 | #endif /* CONFIG_CPU_FREQ */ |
| 83 | |
| 84 | /** |
| 85 | * bfin_dpmc_probe - |
| 86 | * |
| 87 | */ |
| 88 | static int __devinit bfin_dpmc_probe(struct platform_device *pdev) |
| 89 | { |
| 90 | if (pdev->dev.platform_data) |
| 91 | pdata = pdev->dev.platform_data; |
| 92 | else |
| 93 | return -EINVAL; |
| 94 | |
| 95 | return cpufreq_register_notifier(&vreg_cpufreq_notifier_block, |
| 96 | CPUFREQ_TRANSITION_NOTIFIER); |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * bfin_dpmc_remove - |
| 101 | */ |
| 102 | static int __devexit bfin_dpmc_remove(struct platform_device *pdev) |
| 103 | { |
| 104 | pdata = NULL; |
| 105 | return cpufreq_unregister_notifier(&vreg_cpufreq_notifier_block, |
| 106 | CPUFREQ_TRANSITION_NOTIFIER); |
| 107 | } |
| 108 | |
| 109 | struct platform_driver bfin_dpmc_device_driver = { |
| 110 | .probe = bfin_dpmc_probe, |
| 111 | .remove = __devexit_p(bfin_dpmc_remove), |
| 112 | .driver = { |
| 113 | .name = DRIVER_NAME, |
| 114 | } |
| 115 | }; |
| 116 | |
| 117 | /** |
| 118 | * bfin_dpmc_init - Init driver |
| 119 | */ |
| 120 | static int __init bfin_dpmc_init(void) |
| 121 | { |
| 122 | return platform_driver_register(&bfin_dpmc_device_driver); |
| 123 | } |
| 124 | module_init(bfin_dpmc_init); |
| 125 | |
| 126 | /** |
| 127 | * bfin_dpmc_exit - break down driver |
| 128 | */ |
| 129 | static void __exit bfin_dpmc_exit(void) |
| 130 | { |
| 131 | platform_driver_unregister(&bfin_dpmc_device_driver); |
| 132 | } |
| 133 | module_exit(bfin_dpmc_exit); |
| 134 | |
| 135 | MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>"); |
| 136 | MODULE_DESCRIPTION("cpu power management driver for Blackfin"); |
| 137 | MODULE_LICENSE("GPL"); |