drivers/w1/slaves/w1_ds2780.c

   1 /*
   2  * 1-Wire implementation for the ds2780 chip
   3  *
   4  * Copyright (C) 2010 Indesign, LLC
   5  *
   6  * Author: Clifton Barnes <cabarnes@indesign-llc.com>
   7  *
   8  * Based on w1-ds2760 driver
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/device.h>
  19 #include <linux/types.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mutex.h>
  22 #include <linux/idr.h>
  23
  24 #include "../w1.h"
  25 #include "../w1_int.h"
  26 #include "../w1_family.h"
  27 #include "w1_ds2780.h"
  28
  29 static int w1_ds2780_do_io(struct device *dev, char *buf, int addr,
  30                         size_t count, int io)
  31 {
  32         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  33
  34         if (addr > DS2780_DATA_SIZE || addr < 0)
  35                 return 0;
  36
  37         count = min_t(int, count, DS2780_DATA_SIZE - addr);
  38
  39         if (w1_reset_select_slave(sl) == 0) {
  40                 if (io) {
  41                         w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
  42                         w1_write_8(sl->master, addr);
  43                         w1_write_block(sl->master, buf, count);
  44                 } else {
  45                         w1_write_8(sl->master, W1_DS2780_READ_DATA);
  46                         w1_write_8(sl->master, addr);
  47                         count = w1_read_block(sl->master, buf, count);
  48                 }
  49         }
  50
  51         return count;
  52 }
  53
  54 int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
  55                         int io)
  56 {
  57         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  58         int ret;
  59
  60         if (!dev)
  61                 return -ENODEV;
  62
  63         mutex_lock(&sl->master->bus_mutex);
  64
  65         ret = w1_ds2780_do_io(dev, buf, addr, count, io);
  66
  67         mutex_unlock(&sl->master->bus_mutex);
  68
  69         return ret;
  70 }
  71 EXPORT_SYMBOL(w1_ds2780_io);
  72
  73 int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
  74 {
  75         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  76
  77         if (!dev)
  78                 return -EINVAL;
  79
  80         mutex_lock(&sl->master->bus_mutex);
  81
  82         if (w1_reset_select_slave(sl) == 0) {
  83                 w1_write_8(sl->master, cmd);
  84                 w1_write_8(sl->master, addr);
  85         }
  86
  87         mutex_unlock(&sl->master->bus_mutex);
  88         return 0;
  89 }
  90 EXPORT_SYMBOL(w1_ds2780_eeprom_cmd);
  91
  92 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
  93                              struct bin_attribute *bin_attr, char *buf,
  94                              loff_t off, size_t count)
  95 {
  96         struct device *dev = container_of(kobj, struct device, kobj);
  97         return w1_ds2780_io(dev, buf, off, count, 0);
  98 }
  99
 100 static BIN_ATTR_RO(w1_slave, DS2780_DATA_SIZE);
 101
 102 static struct bin_attribute *w1_ds2780_bin_attrs[] = {
 103         &bin_attr_w1_slave,
 104         NULL,
 105 };
 106
 107 static const struct attribute_group w1_ds2780_group = {
 108         .bin_attrs = w1_ds2780_bin_attrs,
 109 };
 110
 111 static const struct attribute_group *w1_ds2780_groups[] = {
 112         &w1_ds2780_group,
 113         NULL,
 114 };
 115
 116 static DEFINE_IDA(bat_ida);
 117
 118 static int w1_ds2780_add_slave(struct w1_slave *sl)
 119 {
 120         int ret;
 121         int id;
 122         struct platform_device *pdev;
 123
 124         id = ida_simple_get(&bat_ida, 0, 0, GFP_KERNEL);
 125         if (id < 0) {
 126                 ret = id;
 127                 goto noid;
 128         }
 129
 130         pdev = platform_device_alloc("ds2780-battery", id);
 131         if (!pdev) {
 132                 ret = -ENOMEM;
 133                 goto pdev_alloc_failed;
 134         }
 135         pdev->dev.parent = &sl->dev;
 136
 137         ret = platform_device_add(pdev);
 138         if (ret)
 139                 goto pdev_add_failed;
 140
 141         dev_set_drvdata(&sl->dev, pdev);
 142
 143         return 0;
 144
 145 pdev_add_failed:
 146         platform_device_put(pdev);
 147 pdev_alloc_failed:
 148         ida_simple_remove(&bat_ida, id);
 149 noid:
 150         return ret;
 151 }
 152
 153 static void w1_ds2780_remove_slave(struct w1_slave *sl)
 154 {
 155         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 156         int id = pdev->id;
 157
 158         platform_device_unregister(pdev);
 159         ida_simple_remove(&bat_ida, id);
 160 }
 161
 162 static struct w1_family_ops w1_ds2780_fops = {
 163         .add_slave    = w1_ds2780_add_slave,
 164         .remove_slave = w1_ds2780_remove_slave,
 165         .groups       = w1_ds2780_groups,
 166 };
 167
 168 static struct w1_family w1_ds2780_family = {
 169         .fid = W1_FAMILY_DS2780,
 170         .fops = &w1_ds2780_fops,
 171 };
 172
 173 static int __init w1_ds2780_init(void)
 174 {
 175         ida_init(&bat_ida);
 176         return w1_register_family(&w1_ds2780_family);
 177 }
 178
 179 static void __exit w1_ds2780_exit(void)
 180 {
 181         w1_unregister_family(&w1_ds2780_family);
 182         ida_destroy(&bat_ida);
 183 }
 184
 185 module_init(w1_ds2780_init);
 186 module_exit(w1_ds2780_exit);
 187
 188 MODULE_LICENSE("GPL");
 189 MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
 190 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");
 191 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2780));