drivers/w1/slaves/w1_ds2781.c

   1 /*
   2  * 1-Wire implementation for the ds2781 chip
   3  *
   4  * Author: Renata Sayakhova <renata@oktetlabs.ru>
   5  *
   6  * Based on w1-ds2780 driver
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/types.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/mutex.h>
  20
  21 #include "../w1.h"
  22 #include "../w1_int.h"
  23 #include "../w1_family.h"
  24 #include "w1_ds2781.h"
  25
  26 static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
  27                         size_t count, int io)
  28 {
  29         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  30
  31         if (addr > DS2781_DATA_SIZE || addr < 0)
  32                 return 0;
  33
  34         count = min_t(int, count, DS2781_DATA_SIZE - addr);
  35
  36         if (w1_reset_select_slave(sl) == 0) {
  37                 if (io) {
  38                         w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
  39                         w1_write_8(sl->master, addr);
  40                         w1_write_block(sl->master, buf, count);
  41                 } else {
  42                         w1_write_8(sl->master, W1_DS2781_READ_DATA);
  43                         w1_write_8(sl->master, addr);
  44                         count = w1_read_block(sl->master, buf, count);
  45                 }
  46         }
  47
  48         return count;
  49 }
  50
  51 int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
  52                         int io)
  53 {
  54         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  55         int ret;
  56
  57         if (!dev)
  58                 return -ENODEV;
  59
  60         mutex_lock(&sl->master->bus_mutex);
  61
  62         ret = w1_ds2781_do_io(dev, buf, addr, count, io);
  63
  64         mutex_unlock(&sl->master->bus_mutex);
  65
  66         return ret;
  67 }
  68 EXPORT_SYMBOL(w1_ds2781_io);
  69
  70 int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
  71 {
  72         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  73
  74         if (!dev)
  75                 return -EINVAL;
  76
  77         mutex_lock(&sl->master->bus_mutex);
  78
  79         if (w1_reset_select_slave(sl) == 0) {
  80                 w1_write_8(sl->master, cmd);
  81                 w1_write_8(sl->master, addr);
  82         }
  83
  84         mutex_unlock(&sl->master->bus_mutex);
  85         return 0;
  86 }
  87 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
  88
  89 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
  90                              struct bin_attribute *bin_attr, char *buf,
  91                              loff_t off, size_t count)
  92 {
  93         struct device *dev = container_of(kobj, struct device, kobj);
  94         return w1_ds2781_io(dev, buf, off, count, 0);
  95 }
  96
  97 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
  98
  99 static struct bin_attribute *w1_ds2781_bin_attrs[] = {
 100         &bin_attr_w1_slave,
 101         NULL,
 102 };
 103
 104 static const struct attribute_group w1_ds2781_group = {
 105         .bin_attrs = w1_ds2781_bin_attrs,
 106 };
 107
 108 static const struct attribute_group *w1_ds2781_groups[] = {
 109         &w1_ds2781_group,
 110         NULL,
 111 };
 112
 113 static int w1_ds2781_add_slave(struct w1_slave *sl)
 114 {
 115         int ret;
 116         struct platform_device *pdev;
 117
 118         pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
 119         if (!pdev)
 120                 return -ENOMEM;
 121         pdev->dev.parent = &sl->dev;
 122
 123         ret = platform_device_add(pdev);
 124         if (ret)
 125                 goto pdev_add_failed;
 126
 127         dev_set_drvdata(&sl->dev, pdev);
 128
 129         return 0;
 130
 131 pdev_add_failed:
 132         platform_device_put(pdev);
 133
 134         return ret;
 135 }
 136
 137 static void w1_ds2781_remove_slave(struct w1_slave *sl)
 138 {
 139         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 140
 141         platform_device_unregister(pdev);
 142 }
 143
 144 static struct w1_family_ops w1_ds2781_fops = {
 145         .add_slave    = w1_ds2781_add_slave,
 146         .remove_slave = w1_ds2781_remove_slave,
 147         .groups       = w1_ds2781_groups,
 148 };
 149
 150 static struct w1_family w1_ds2781_family = {
 151         .fid = W1_FAMILY_DS2781,
 152         .fops = &w1_ds2781_fops,
 153 };
 154 module_w1_family(w1_ds2781_family);
 155
 156 MODULE_LICENSE("GPL");
 157 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
 158 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
 159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));