linux/drivers/mfd/retu-mfd.c
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   1/*
   2 * Retu MFD driver
   3 *
   4 * Copyright (C) 2004, 2005 Nokia Corporation
   5 *
   6 * Based on code written by Juha Yrjölä, David Weinehall and Mikko Ylinen.
   7 * Rewritten by Aaro Koskinen.
   8 *
   9 * This file is subject to the terms and conditions of the GNU General
  10 * Public License. See the file "COPYING" in the main directory of this
  11 * archive for more details.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16 * GNU General Public License for more details.
  17 */
  18
  19#include <linux/err.h>
  20#include <linux/i2c.h>
  21#include <linux/irq.h>
  22#include <linux/init.h>
  23#include <linux/slab.h>
  24#include <linux/mutex.h>
  25#include <linux/module.h>
  26#include <linux/regmap.h>
  27#include <linux/mfd/core.h>
  28#include <linux/mfd/retu.h>
  29#include <linux/interrupt.h>
  30#include <linux/moduleparam.h>
  31
  32/* Registers */
  33#define RETU_REG_ASICR          0x00            /* ASIC ID and revision */
  34#define RETU_REG_ASICR_VILMA    (1 << 7)        /* Bit indicating Vilma */
  35#define RETU_REG_IDR            0x01            /* Interrupt ID */
  36#define RETU_REG_IMR            0x02            /* Interrupt mask */
  37
  38/* Interrupt sources */
  39#define RETU_INT_PWR            0               /* Power button */
  40
  41struct retu_dev {
  42        struct regmap                   *regmap;
  43        struct device                   *dev;
  44        struct mutex                    mutex;
  45        struct regmap_irq_chip_data     *irq_data;
  46};
  47
  48static struct resource retu_pwrbutton_res[] = {
  49        {
  50                .name   = "retu-pwrbutton",
  51                .start  = RETU_INT_PWR,
  52                .end    = RETU_INT_PWR,
  53                .flags  = IORESOURCE_IRQ,
  54        },
  55};
  56
  57static struct mfd_cell retu_devs[] = {
  58        {
  59                .name           = "retu-wdt"
  60        },
  61        {
  62                .name           = "retu-pwrbutton",
  63                .resources      = retu_pwrbutton_res,
  64                .num_resources  = ARRAY_SIZE(retu_pwrbutton_res),
  65        }
  66};
  67
  68static struct regmap_irq retu_irqs[] = {
  69        [RETU_INT_PWR] = {
  70                .mask = 1 << RETU_INT_PWR,
  71        }
  72};
  73
  74static struct regmap_irq_chip retu_irq_chip = {
  75        .name           = "RETU",
  76        .irqs           = retu_irqs,
  77        .num_irqs       = ARRAY_SIZE(retu_irqs),
  78        .num_regs       = 1,
  79        .status_base    = RETU_REG_IDR,
  80        .mask_base      = RETU_REG_IMR,
  81        .ack_base       = RETU_REG_IDR,
  82};
  83
  84/* Retu device registered for the power off. */
  85static struct retu_dev *retu_pm_power_off;
  86
  87int retu_read(struct retu_dev *rdev, u8 reg)
  88{
  89        int ret;
  90        int value;
  91
  92        mutex_lock(&rdev->mutex);
  93        ret = regmap_read(rdev->regmap, reg, &value);
  94        mutex_unlock(&rdev->mutex);
  95
  96        return ret ? ret : value;
  97}
  98EXPORT_SYMBOL_GPL(retu_read);
  99
 100int retu_write(struct retu_dev *rdev, u8 reg, u16 data)
 101{
 102        int ret;
 103
 104        mutex_lock(&rdev->mutex);
 105        ret = regmap_write(rdev->regmap, reg, data);
 106        mutex_unlock(&rdev->mutex);
 107
 108        return ret;
 109}
 110EXPORT_SYMBOL_GPL(retu_write);
 111
 112static void retu_power_off(void)
 113{
 114        struct retu_dev *rdev = retu_pm_power_off;
 115        int reg;
 116
 117        mutex_lock(&retu_pm_power_off->mutex);
 118
 119        /* Ignore power button state */
 120        regmap_read(rdev->regmap, RETU_REG_CC1, &reg);
 121        regmap_write(rdev->regmap, RETU_REG_CC1, reg | 2);
 122
 123        /* Expire watchdog immediately */
 124        regmap_write(rdev->regmap, RETU_REG_WATCHDOG, 0);
 125
 126        /* Wait for poweroff */
 127        for (;;)
 128                cpu_relax();
 129
 130        mutex_unlock(&retu_pm_power_off->mutex);
 131}
 132
 133static int retu_regmap_read(void *context, const void *reg, size_t reg_size,
 134                            void *val, size_t val_size)
 135{
 136        int ret;
 137        struct device *dev = context;
 138        struct i2c_client *i2c = to_i2c_client(dev);
 139
 140        BUG_ON(reg_size != 1 || val_size != 2);
 141
 142        ret = i2c_smbus_read_word_data(i2c, *(u8 const *)reg);
 143        if (ret < 0)
 144                return ret;
 145
 146        *(u16 *)val = ret;
 147        return 0;
 148}
 149
 150static int retu_regmap_write(void *context, const void *data, size_t count)
 151{
 152        u8 reg;
 153        u16 val;
 154        struct device *dev = context;
 155        struct i2c_client *i2c = to_i2c_client(dev);
 156
 157        BUG_ON(count != sizeof(reg) + sizeof(val));
 158        memcpy(&reg, data, sizeof(reg));
 159        memcpy(&val, data + sizeof(reg), sizeof(val));
 160        return i2c_smbus_write_word_data(i2c, reg, val);
 161}
 162
 163static struct regmap_bus retu_bus = {
 164        .read = retu_regmap_read,
 165        .write = retu_regmap_write,
 166        .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
 167};
 168
 169static struct regmap_config retu_config = {
 170        .reg_bits = 8,
 171        .val_bits = 16,
 172};
 173
 174static int retu_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
 175{
 176        struct retu_dev *rdev;
 177        int ret;
 178
 179        rdev = devm_kzalloc(&i2c->dev, sizeof(*rdev), GFP_KERNEL);
 180        if (rdev == NULL)
 181                return -ENOMEM;
 182
 183        i2c_set_clientdata(i2c, rdev);
 184        rdev->dev = &i2c->dev;
 185        mutex_init(&rdev->mutex);
 186        rdev->regmap = devm_regmap_init(&i2c->dev, &retu_bus, &i2c->dev,
 187                                        &retu_config);
 188        if (IS_ERR(rdev->regmap))
 189                return PTR_ERR(rdev->regmap);
 190
 191        ret = retu_read(rdev, RETU_REG_ASICR);
 192        if (ret < 0) {
 193                dev_err(rdev->dev, "could not read Retu revision: %d\n", ret);
 194                return ret;
 195        }
 196
 197        dev_info(rdev->dev, "Retu%s v%d.%d found\n",
 198                 (ret & RETU_REG_ASICR_VILMA) ? " & Vilma" : "",
 199                 (ret >> 4) & 0x7, ret & 0xf);
 200
 201        /* Mask all RETU interrupts. */
 202        ret = retu_write(rdev, RETU_REG_IMR, 0xffff);
 203        if (ret < 0)
 204                return ret;
 205
 206        ret = regmap_add_irq_chip(rdev->regmap, i2c->irq, IRQF_ONESHOT, -1,
 207                                  &retu_irq_chip, &rdev->irq_data);
 208        if (ret < 0)
 209                return ret;
 210
 211        ret = mfd_add_devices(rdev->dev, -1, retu_devs, ARRAY_SIZE(retu_devs),
 212                              NULL, regmap_irq_chip_get_base(rdev->irq_data),
 213                              NULL);
 214        if (ret < 0) {
 215                regmap_del_irq_chip(i2c->irq, rdev->irq_data);
 216                return ret;
 217        }
 218
 219        if (!pm_power_off) {
 220                retu_pm_power_off = rdev;
 221                pm_power_off      = retu_power_off;
 222        }
 223
 224        return 0;
 225}
 226
 227static int retu_remove(struct i2c_client *i2c)
 228{
 229        struct retu_dev *rdev = i2c_get_clientdata(i2c);
 230
 231        if (retu_pm_power_off == rdev) {
 232                pm_power_off      = NULL;
 233                retu_pm_power_off = NULL;
 234        }
 235        mfd_remove_devices(rdev->dev);
 236        regmap_del_irq_chip(i2c->irq, rdev->irq_data);
 237
 238        return 0;
 239}
 240
 241static const struct i2c_device_id retu_id[] = {
 242        { "retu-mfd", 0 },
 243        { }
 244};
 245MODULE_DEVICE_TABLE(i2c, retu_id);
 246
 247static struct i2c_driver retu_driver = {
 248        .driver         = {
 249                .name = "retu-mfd",
 250                .owner = THIS_MODULE,
 251        },
 252        .probe          = retu_probe,
 253        .remove         = retu_remove,
 254        .id_table       = retu_id,
 255};
 256module_i2c_driver(retu_driver);
 257
 258MODULE_DESCRIPTION("Retu MFD driver");
 259MODULE_AUTHOR("Juha Yrjölä");
 260MODULE_AUTHOR("David Weinehall");
 261MODULE_AUTHOR("Mikko Ylinen");
 262MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
 263MODULE_LICENSE("GPL");
 264
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