drivers/hwmon/ams/ams-pmu.c

   1 /*
   2  * Apple Motion Sensor driver (PMU variant)
   3  *
   4  * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/adb.h>
  17 #include <linux/pmu.h>
  18
  19 #include "ams.h"
  20
  21 /* Attitude */
  22 #define AMS_X                   0x00
  23 #define AMS_Y                   0x01
  24 #define AMS_Z                   0x02
  25
  26 /* Not exactly known, maybe chip vendor */
  27 #define AMS_VENDOR              0x03
  28
  29 /* Freefall registers */
  30 #define AMS_FF_CLEAR            0x04
  31 #define AMS_FF_ENABLE           0x05
  32 #define AMS_FF_LOW_LIMIT        0x06
  33 #define AMS_FF_DEBOUNCE         0x07
  34
  35 /* Shock registers */
  36 #define AMS_SHOCK_CLEAR         0x08
  37 #define AMS_SHOCK_ENABLE        0x09
  38 #define AMS_SHOCK_HIGH_LIMIT    0x0a
  39 #define AMS_SHOCK_DEBOUNCE      0x0b
  40
  41 /* Global interrupt and power control register */
  42 #define AMS_CONTROL             0x0c
  43
  44 static u8 ams_pmu_cmd;
  45
  46 static void ams_pmu_req_complete(struct adb_request *req)
  47 {
  48         complete((struct completion *)req->arg);
  49 }
  50
  51 /* Only call this function from task context */
  52 static void ams_pmu_set_register(u8 reg, u8 value)
  53 {
  54         static struct adb_request req;
  55         DECLARE_COMPLETION(req_complete);
  56
  57         req.arg = &req_complete;
  58         if (pmu_request(&req, ams_pmu_req_complete, 4, ams_pmu_cmd, 0x00, reg, value))
  59                 return;
  60
  61         wait_for_completion(&req_complete);
  62 }
  63
  64 /* Only call this function from task context */
  65 static u8 ams_pmu_get_register(u8 reg)
  66 {
  67         static struct adb_request req;
  68         DECLARE_COMPLETION(req_complete);
  69
  70         req.arg = &req_complete;
  71         if (pmu_request(&req, ams_pmu_req_complete, 3, ams_pmu_cmd, 0x01, reg))
  72                 return 0;
  73
  74         wait_for_completion(&req_complete);
  75
  76         if (req.reply_len > 0)
  77                 return req.reply[0];
  78         else
  79                 return 0;
  80 }
  81
  82 /* Enables or disables the specified interrupts */
  83 static void ams_pmu_set_irq(enum ams_irq reg, char enable)
  84 {
  85         if (reg & AMS_IRQ_FREEFALL) {
  86                 u8 val = ams_pmu_get_register(AMS_FF_ENABLE);
  87                 if (enable)
  88                         val |= 0x80;
  89                 else
  90                         val &= ~0x80;
  91                 ams_pmu_set_register(AMS_FF_ENABLE, val);
  92         }
  93
  94         if (reg & AMS_IRQ_SHOCK) {
  95                 u8 val = ams_pmu_get_register(AMS_SHOCK_ENABLE);
  96                 if (enable)
  97                         val |= 0x80;
  98                 else
  99                         val &= ~0x80;
 100                 ams_pmu_set_register(AMS_SHOCK_ENABLE, val);
 101         }
 102
 103         if (reg & AMS_IRQ_GLOBAL) {
 104                 u8 val = ams_pmu_get_register(AMS_CONTROL);
 105                 if (enable)
 106                         val |= 0x80;
 107                 else
 108                         val &= ~0x80;
 109                 ams_pmu_set_register(AMS_CONTROL, val);
 110         }
 111 }
 112
 113 static void ams_pmu_clear_irq(enum ams_irq reg)
 114 {
 115         if (reg & AMS_IRQ_FREEFALL)
 116                 ams_pmu_set_register(AMS_FF_CLEAR, 0x00);
 117
 118         if (reg & AMS_IRQ_SHOCK)
 119                 ams_pmu_set_register(AMS_SHOCK_CLEAR, 0x00);
 120 }
 121
 122 static u8 ams_pmu_get_vendor(void)
 123 {
 124         return ams_pmu_get_register(AMS_VENDOR);
 125 }
 126
 127 static void ams_pmu_get_xyz(s8 *x, s8 *y, s8 *z)
 128 {
 129         *x = ams_pmu_get_register(AMS_X);
 130         *y = ams_pmu_get_register(AMS_Y);
 131         *z = ams_pmu_get_register(AMS_Z);
 132 }
 133
 134 static void ams_pmu_exit(void)
 135 {
 136         /* Disable interrupts */
 137         ams_pmu_set_irq(AMS_IRQ_ALL, 0);
 138
 139         /* Clear interrupts */
 140         ams_pmu_clear_irq(AMS_IRQ_ALL);
 141
 142         ams_info.has_device = 0;
 143
 144         printk(KERN_INFO "ams: Unloading\n");
 145 }
 146
 147 int __init ams_pmu_init(struct device_node *np)
 148 {
 149         const u32 *prop;
 150         int result;
 151
 152         mutex_lock(&ams_info.lock);
 153
 154         /* Set implementation stuff */
 155         ams_info.of_node = np;
 156         ams_info.exit = ams_pmu_exit;
 157         ams_info.get_vendor = ams_pmu_get_vendor;
 158         ams_info.get_xyz = ams_pmu_get_xyz;
 159         ams_info.clear_irq = ams_pmu_clear_irq;
 160         ams_info.bustype = BUS_HOST;
 161
 162         /* Get PMU command, should be 0x4e, but we can never know */
 163         prop = of_get_property(ams_info.of_node, "reg", NULL);
 164         if (!prop) {
 165                 result = -ENODEV;
 166                 goto exit;
 167         }
 168         ams_pmu_cmd = ((*prop) >> 8) & 0xff;
 169
 170         /* Disable interrupts */
 171         ams_pmu_set_irq(AMS_IRQ_ALL, 0);
 172
 173         /* Clear interrupts */
 174         ams_pmu_clear_irq(AMS_IRQ_ALL);
 175
 176         result = ams_sensor_attach();
 177         if (result < 0)
 178                 goto exit;
 179
 180         /* Set default values */
 181         ams_pmu_set_register(AMS_FF_LOW_LIMIT, 0x15);
 182         ams_pmu_set_register(AMS_FF_ENABLE, 0x08);
 183         ams_pmu_set_register(AMS_FF_DEBOUNCE, 0x14);
 184
 185         ams_pmu_set_register(AMS_SHOCK_HIGH_LIMIT, 0x60);
 186         ams_pmu_set_register(AMS_SHOCK_ENABLE, 0x0f);
 187         ams_pmu_set_register(AMS_SHOCK_DEBOUNCE, 0x14);
 188
 189         ams_pmu_set_register(AMS_CONTROL, 0x4f);
 190
 191         /* Clear interrupts */
 192         ams_pmu_clear_irq(AMS_IRQ_ALL);
 193
 194         ams_info.has_device = 1;
 195
 196         /* Enable interrupts */
 197         ams_pmu_set_irq(AMS_IRQ_ALL, 1);
 198
 199         printk(KERN_INFO "ams: Found PMU based motion sensor\n");
 200
 201         result = 0;
 202
 203 exit:
 204         mutex_unlock(&ams_info.lock);
 205
 206         return result;
 207 }