drivers/w1/slaves/w1_ds2781.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * 1-Wire implementation for the ds2781 chip
   4  *
   5  * Author: Renata Sayakhova <renata@oktetlabs.ru>
   6  *
   7  * Based on w1-ds2780 driver
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/device.h>
  13 #include <linux/types.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/mutex.h>
  16
  17 #include <linux/w1.h>
  18
  19 #include "w1_ds2781.h"
  20
  21 #define W1_FAMILY_DS2781        0x3D
  22
  23 static int w1_ds2781_do_io(struct device *dev, char *buf, int addr,
  24                         size_t count, int io)
  25 {
  26         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  27
  28         if (addr > DS2781_DATA_SIZE || addr < 0)
  29                 return 0;
  30
  31         count = min_t(int, count, DS2781_DATA_SIZE - addr);
  32
  33         if (w1_reset_select_slave(sl) == 0) {
  34                 if (io) {
  35                         w1_write_8(sl->master, W1_DS2781_WRITE_DATA);
  36                         w1_write_8(sl->master, addr);
  37                         w1_write_block(sl->master, buf, count);
  38                 } else {
  39                         w1_write_8(sl->master, W1_DS2781_READ_DATA);
  40                         w1_write_8(sl->master, addr);
  41                         count = w1_read_block(sl->master, buf, count);
  42                 }
  43         }
  44
  45         return count;
  46 }
  47
  48 int w1_ds2781_io(struct device *dev, char *buf, int addr, size_t count,
  49                         int io)
  50 {
  51         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  52         int ret;
  53
  54         if (!dev)
  55                 return -ENODEV;
  56
  57         mutex_lock(&sl->master->bus_mutex);
  58
  59         ret = w1_ds2781_do_io(dev, buf, addr, count, io);
  60
  61         mutex_unlock(&sl->master->bus_mutex);
  62
  63         return ret;
  64 }
  65 EXPORT_SYMBOL(w1_ds2781_io);
  66
  67 int w1_ds2781_eeprom_cmd(struct device *dev, int addr, int cmd)
  68 {
  69         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  70
  71         if (!dev)
  72                 return -EINVAL;
  73
  74         mutex_lock(&sl->master->bus_mutex);
  75
  76         if (w1_reset_select_slave(sl) == 0) {
  77                 w1_write_8(sl->master, cmd);
  78                 w1_write_8(sl->master, addr);
  79         }
  80
  81         mutex_unlock(&sl->master->bus_mutex);
  82         return 0;
  83 }
  84 EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
  85
  86 static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
  87                              struct bin_attribute *bin_attr, char *buf,
  88                              loff_t off, size_t count)
  89 {
  90         struct device *dev = kobj_to_dev(kobj);
  91
  92         return w1_ds2781_io(dev, buf, off, count, 0);
  93 }
  94
  95 static BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
  96
  97 static struct bin_attribute *w1_ds2781_bin_attrs[] = {
  98         &bin_attr_w1_slave,
  99         NULL,
 100 };
 101
 102 static const struct attribute_group w1_ds2781_group = {
 103         .bin_attrs = w1_ds2781_bin_attrs,
 104 };
 105
 106 static const struct attribute_group *w1_ds2781_groups[] = {
 107         &w1_ds2781_group,
 108         NULL,
 109 };
 110
 111 static int w1_ds2781_add_slave(struct w1_slave *sl)
 112 {
 113         int ret;
 114         struct platform_device *pdev;
 115
 116         pdev = platform_device_alloc("ds2781-battery", PLATFORM_DEVID_AUTO);
 117         if (!pdev)
 118                 return -ENOMEM;
 119         pdev->dev.parent = &sl->dev;
 120
 121         ret = platform_device_add(pdev);
 122         if (ret)
 123                 goto pdev_add_failed;
 124
 125         dev_set_drvdata(&sl->dev, pdev);
 126
 127         return 0;
 128
 129 pdev_add_failed:
 130         platform_device_put(pdev);
 131
 132         return ret;
 133 }
 134
 135 static void w1_ds2781_remove_slave(struct w1_slave *sl)
 136 {
 137         struct platform_device *pdev = dev_get_drvdata(&sl->dev);
 138
 139         platform_device_unregister(pdev);
 140 }
 141
 142 static const struct w1_family_ops w1_ds2781_fops = {
 143         .add_slave    = w1_ds2781_add_slave,
 144         .remove_slave = w1_ds2781_remove_slave,
 145         .groups       = w1_ds2781_groups,
 146 };
 147
 148 static struct w1_family w1_ds2781_family = {
 149         .fid = W1_FAMILY_DS2781,
 150         .fops = &w1_ds2781_fops,
 151 };
 152 module_w1_family(w1_ds2781_family);
 153
 154 MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
 155 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
 156 MODULE_LICENSE("GPL");
 157 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));