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
w1_ds2781_do_io(struct device * dev,char * buf,int addr,size_t count,int io)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
w1_ds2781_io(struct device * dev,char * buf,int addr,size_t count,int io)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
w1_ds2781_eeprom_cmd(struct device * dev,int addr,int cmd)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
w1_slave_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)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
w1_ds2781_add_slave(struct w1_slave * sl)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
w1_ds2781_remove_slave(struct w1_slave * sl)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));
158