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 <linux/w1.h>
  22
  23 #include "w1_ds2781.h"
  24
  25 #define W1_FAMILY_DS2781        0x3D
  26
  27 static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
  28                         size_t count, int io)
  29 {
  30         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  31
  32         if (addr > DS2781_DATA_SIZE || addr < 0)
  33                 return 0;
  34
  35         count = min_t(int, count, DS2781_DATA_SIZE - addr);
  36
  37         if (w1_reset_select_slave(sl) == 0) {
  38                 if (io) {
  39                         w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
  40                         w1_write_8(sl->master, addr);
  41                         w1_write_block(sl->master, buf, count);
  42                 } else {
  43                         w1_write_8(sl->master, W1_DS2781_READ_DATA);
  44                         w1_write_8(sl->master, addr);
  45                         count = w1_read_block(sl->master, buf, count);
  46                 }
  47         }
  48
  49         return count;
  50 }
  51
  52 int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
  53                         int io)
  54 {
  55         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  56         int ret;
  57
  58         if (!dev)
  59                 return -ENODEV;
  60
  61         mutex_lock(&sl->master->bus_mutex);
  62
  63         ret = w1_ds2781_do_io(dev, buf, addr, count, io);
  64
  65         mutex_unlock(&sl->master->bus_mutex);
  66
  67         return ret;
  68 }
  69 EXPORT_SYMBOL(w1_ds2781_io);
  70
  71 int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
  72 {
  73         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  74
  75         if (!dev)
  76                 return -EINVAL;
  77
  78         mutex_lock(&sl->master->bus_mutex);
  79
  80         if (w1_reset_select_slave(sl) == 0) {
  81                 w1_write_8(sl->master, cmd);
  82                 w1_write_8(sl->master, addr);
  83         }
  84
  85         mutex_unlock(&sl->master->bus_mutex);
  86         return 0;
  87 }
  88 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
  89
  90 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
  91                              struct bin_attribute *bin_attr, char *buf,
  92                              loff_t off, size_t count)
  93 {
  94         struct device *dev = container_of(kobj, struct device, kobj);
  95         return w1_ds2781_io(dev, buf, off, count, 0);
  96 }
  97
  98 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
  99
 100 static struct bin_attribute *w1_ds2781_bin_attrs[] = {
 101         &bin_attr_w1_slave,
 102         NULL,
 103 };
 104
 105 static const struct attribute_group w1_ds2781_group = {
 106         .bin_attrs = w1_ds2781_bin_attrs,
 107 };
 108
 109 static const struct attribute_group *w1_ds2781_groups[] = {
 110         &w1_ds2781_group,
 111         NULL,
 112 };
 113
 114 static int w1_ds2781_add_slave(struct w1_slave *sl)
 115 {
 116         int ret;
 117         struct platform_device *pdev;
 118
 119         pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
 120         if (!pdev)
 121                 return -ENOMEM;
 122         pdev->dev.parent = &sl->dev;
 123
 124         ret = platform_device_add(pdev);
 125         if (ret)
 126                 goto pdev_add_failed;
 127
 128         dev_set_drvdata(&sl->dev, pdev);
 129
 130         return 0;
 131
 132 pdev_add_failed:
 133         platform_device_put(pdev);
 134
 135         return ret;
 136 }
 137
 138 static void w1_ds2781_remove_slave(struct w1_slave *sl)
 139 {
 140         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 141
 142         platform_device_unregister(pdev);
 143 }
 144
 145 static struct w1_family_ops w1_ds2781_fops = {
 146         .add_slave    = w1_ds2781_add_slave,
 147         .remove_slave = w1_ds2781_remove_slave,
 148         .groups       = w1_ds2781_groups,
 149 };
 150
 151 static struct w1_family w1_ds2781_family = {
 152         .fid = W1_FAMILY_DS2781,
 153         .fops = &w1_ds2781_fops,
 154 };
 155 module_w1_family(w1_ds2781_family);
 156
 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_LICENSE("GPL");
 160 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));