arch/arm/mach-pxa/mfp.c

   1 /*
   2  * linux/arch/arm/mach-pxa/mfp.c
   3  *
   4  * PXA3xx Multi-Function Pin Support
   5  *
   6  * Copyright (C) 2007 Marvell Internation Ltd.
   7  *
   8  * 2007-08-21: eric miao <eric.miao@marvell.com>
   9  *             initial version
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License version 2 as
  13  *  published by the Free Software Foundation.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/io.h>
  20 #include <linux/sysdev.h>
  21
  22 #include <asm/hardware.h>
  23 #include <asm/arch/mfp.h>
  24 #include <asm/arch/mfp-pxa3xx.h>
  25 #include <asm/arch/pxa3xx-regs.h>
  26
  27 /* mfp_spin_lock is used to ensure that MFP register configuration
  28  * (most likely a read-modify-write operation) is atomic, and that
  29  * mfp_table[] is consistent
  30  */
  31 static DEFINE_SPINLOCK(mfp_spin_lock);
  32
  33 static void __iomem *mfpr_mmio_base = (void __iomem *)&__REG(MFPR_BASE);
  34
  35 struct pxa3xx_mfp_pin {
  36         unsigned long   config;         /* -1 for not configured */
  37         unsigned long   mfpr_off;       /* MFPRxx Register offset */
  38         unsigned long   mfpr_run;       /* Run-Mode Register Value */
  39         unsigned long   mfpr_lpm;       /* Low Power Mode Register Value */
  40 };
  41
  42 static struct pxa3xx_mfp_pin mfp_table[MFP_PIN_MAX];
  43
  44 /* mapping of MFP_LPM_* definitions to MFPR_LPM_* register bits */
  45 const static unsigned long mfpr_lpm[] = {
  46         MFPR_LPM_INPUT,
  47         MFPR_LPM_DRIVE_LOW,
  48         MFPR_LPM_DRIVE_HIGH,
  49         MFPR_LPM_PULL_LOW,
  50         MFPR_LPM_PULL_HIGH,
  51         MFPR_LPM_FLOAT,
  52 };
  53
  54 /* mapping of MFP_PULL_* definitions to MFPR_PULL_* register bits */
  55 const static unsigned long mfpr_pull[] = {
  56         MFPR_PULL_NONE,
  57         MFPR_PULL_LOW,
  58         MFPR_PULL_HIGH,
  59         MFPR_PULL_BOTH,
  60 };
  61
  62 /* mapping of MFP_LPM_EDGE_* definitions to MFPR_EDGE_* register bits */
  63 const static unsigned long mfpr_edge[] = {
  64         MFPR_EDGE_NONE,
  65         MFPR_EDGE_RISE,
  66         MFPR_EDGE_FALL,
  67         MFPR_EDGE_BOTH,
  68 };
  69
  70 #define mfpr_readl(off)                 \
  71         __raw_readl(mfpr_mmio_base + (off))
  72
  73 #define mfpr_writel(off, val)           \
  74         __raw_writel(val, mfpr_mmio_base + (off))
  75
  76 #define mfp_configured(p)       ((p)->config != -1)
  77
  78 /*
  79  * perform a read-back of any MFPR register to make sure the
  80  * previous writings are finished
  81  */
  82 #define mfpr_sync()     (void)__raw_readl(mfpr_mmio_base + 0)
  83
  84 static inline void __mfp_config_run(struct pxa3xx_mfp_pin *p)
  85 {
  86         if (mfp_configured(p))
  87                 mfpr_writel(p->mfpr_off, p->mfpr_run);
  88 }
  89
  90 static inline void __mfp_config_lpm(struct pxa3xx_mfp_pin *p)
  91 {
  92         if (mfp_configured(p)) {
  93                 unsigned long mfpr_clr = (p->mfpr_run & ~MFPR_EDGE_BOTH) | MFPR_EDGE_CLEAR;
  94                 if (mfpr_clr != p->mfpr_run)
  95                         mfpr_writel(p->mfpr_off, mfpr_clr);
  96                 if (p->mfpr_lpm != mfpr_clr)
  97                         mfpr_writel(p->mfpr_off, p->mfpr_lpm);
  98         }
  99 }
 100
 101 void pxa3xx_mfp_config(unsigned long *mfp_cfgs, int num)
 102 {
 103         unsigned long flags;
 104         int i;
 105
 106         spin_lock_irqsave(&mfp_spin_lock, flags);
 107
 108         for (i = 0; i < num; i++, mfp_cfgs++) {
 109                 unsigned long tmp, c = *mfp_cfgs;
 110                 struct pxa3xx_mfp_pin *p;
 111                 int pin, af, drv, lpm, edge, pull;
 112
 113                 pin = MFP_PIN(c);
 114                 BUG_ON(pin >= MFP_PIN_MAX);
 115                 p = &mfp_table[pin];
 116
 117                 af  = MFP_AF(c);
 118                 drv = MFP_DS(c);
 119                 lpm = MFP_LPM_STATE(c);
 120                 edge = MFP_LPM_EDGE(c);
 121                 pull = MFP_PULL(c);
 122
 123                 /* run-mode pull settings will conflict with MFPR bits of
 124                  * low power mode state,  calculate mfpr_run and mfpr_lpm
 125                  * individually if pull != MFP_PULL_NONE
 126                  */
 127                 tmp = MFPR_AF_SEL(af) | MFPR_DRIVE(drv);
 128
 129                 if (likely(pull == MFP_PULL_NONE)) {
 130                         p->mfpr_run = tmp | mfpr_lpm[lpm] | mfpr_edge[edge];
 131                         p->mfpr_lpm = p->mfpr_run;
 132                 } else {
 133                         p->mfpr_lpm = tmp | mfpr_lpm[lpm] | mfpr_edge[edge];
 134                         p->mfpr_run = tmp | mfpr_pull[pull];
 135                 }
 136
 137                 p->config = c; __mfp_config_run(p);
 138         }
 139
 140         mfpr_sync();
 141         spin_unlock_irqrestore(&mfp_spin_lock, flags);
 142 }
 143
 144 unsigned long pxa3xx_mfp_read(int mfp)
 145 {
 146         unsigned long val, flags;
 147
 148         BUG_ON(mfp >= MFP_PIN_MAX);
 149
 150         spin_lock_irqsave(&mfp_spin_lock, flags);
 151         val = mfpr_readl(mfp_table[mfp].mfpr_off);
 152         spin_unlock_irqrestore(&mfp_spin_lock, flags);
 153
 154         return val;
 155 }
 156
 157 void pxa3xx_mfp_write(int mfp, unsigned long val)
 158 {
 159         unsigned long flags;
 160
 161         BUG_ON(mfp >= MFP_PIN_MAX);
 162
 163         spin_lock_irqsave(&mfp_spin_lock, flags);
 164         mfpr_writel(mfp_table[mfp].mfpr_off, val);
 165         mfpr_sync();
 166         spin_unlock_irqrestore(&mfp_spin_lock, flags);
 167 }
 168
 169 void __init pxa3xx_mfp_init_addr(struct pxa3xx_mfp_addr_map *map)
 170 {
 171         struct pxa3xx_mfp_addr_map *p;
 172         unsigned long offset, flags;
 173         int i;
 174
 175         spin_lock_irqsave(&mfp_spin_lock, flags);
 176
 177         for (p = map; p->start != MFP_PIN_INVALID; p++) {
 178                 offset = p->offset;
 179                 i = p->start;
 180
 181                 do {
 182                         mfp_table[i].mfpr_off = offset;
 183                         mfp_table[i].mfpr_run = 0;
 184                         mfp_table[i].mfpr_lpm = 0;
 185                         offset += 4; i++;
 186                 } while ((i <= p->end) && (p->end != -1));
 187         }
 188
 189         spin_unlock_irqrestore(&mfp_spin_lock, flags);
 190 }
 191
 192 void __init pxa3xx_init_mfp(void)
 193 {
 194         int i;
 195
 196         for (i = 0; i < ARRAY_SIZE(mfp_table); i++)
 197                 mfp_table[i].config = -1;
 198 }
 199
 200 #ifdef CONFIG_PM
 201 /*
 202  * Configure the MFPs appropriately for suspend/resume.
 203  * FIXME: this should probably depend on which system state we're
 204  * entering - for instance, we might not want to place MFP pins in
 205  * a pull-down mode if they're an active low chip select, and we're
 206  * just entering standby.
 207  */
 208 static int pxa3xx_mfp_suspend(struct sys_device *d, pm_message_t state)
 209 {
 210         int pin;
 211
 212         for (pin = 0; pin < ARRAY_SIZE(mfp_table); pin++) {
 213                 struct pxa3xx_mfp_pin *p = &mfp_table[pin];
 214                 __mfp_config_lpm(p);
 215         }
 216         return 0;
 217 }
 218
 219 static int pxa3xx_mfp_resume(struct sys_device *d)
 220 {
 221         int pin;
 222
 223         for (pin = 0; pin < ARRAY_SIZE(mfp_table); pin++) {
 224                 struct pxa3xx_mfp_pin *p = &mfp_table[pin];
 225                 __mfp_config_run(p);
 226         }
 227
 228         /* clear RDH bit when MFP settings are restored
 229          *
 230          * NOTE: the last 3 bits DxS are write-1-to-clear so carefully
 231          * preserve them here in case they will be referenced later
 232          */
 233         ASCR &= ~(ASCR_RDH | ASCR_D1S | ASCR_D2S | ASCR_D3S);
 234
 235         return 0;
 236 }
 237
 238 static struct sysdev_class mfp_sysclass = {
 239         .name           = "mfp",
 240         .suspend        = pxa3xx_mfp_suspend,
 241         .resume         = pxa3xx_mfp_resume,
 242 };
 243
 244 static struct sys_device mfp_device = {
 245         .id             = 0,
 246         .cls            = &mfp_sysclass,
 247 };
 248
 249 static int __init mfp_init_devicefs(void)
 250 {
 251         sysdev_class_register(&mfp_sysclass);
 252         return sysdev_register(&mfp_device);
 253 }
 254 device_initcall(mfp_init_devicefs);
 255 #endif