1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 1-Wire implementation for the ds2780 chip
4  *
5  * Copyright (C) 2010 Indesign, LLC
6  *
7  * Author: Clifton Barnes <cabarnes@indesign-llc.com>
8  *
9  * Based on w1-ds2760 driver
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/device.h>
15 #include <linux/types.h>
16 #include <linux/platform_device.h>
17 #include <linux/mutex.h>
18 #include <linux/idr.h>
19 
20 #include <linux/w1.h>
21 
22 #include "w1_ds2780.h"
23 
24 #define W1_FAMILY_DS2780	0x32
25 
w1_ds2780_do_io(struct device * dev,char * buf,int addr,size_t count,int io)26 static int w1_ds2780_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 > DS2780_DATA_SIZE || addr < 0)
32 		return 0;
33 
34 	count = min_t(int, count, DS2780_DATA_SIZE - addr);
35 
36 	if (w1_reset_select_slave(sl) == 0) {
37 		if (io) {
38 			w1_write_8(sl->master, W1_DS2780_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_DS2780_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 
w1_ds2780_io(struct device * dev,char * buf,int addr,size_t count,int io)51 int w1_ds2780_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_ds2780_do_io(dev, buf, addr, count, io);
63 
64 	mutex_unlock(&sl->master->bus_mutex);
65 
66 	return ret;
67 }
68 EXPORT_SYMBOL(w1_ds2780_io);
69 
w1_ds2780_eeprom_cmd(struct device * dev,int addr,int cmd)70 int w1_ds2780_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_ds2780_eeprom_cmd);
88 
w1_slave_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t off,size_t count)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 = kobj_to_dev(kobj);
94 	return w1_ds2780_io(dev, buf, off, count, 0);
95 }
96 
97 static BIN_ATTR_RO(w1_slave, DS2780_DATA_SIZE);
98 
99 static struct bin_attribute *w1_ds2780_bin_attrs[] = {
100 	&bin_attr_w1_slave,
101 	NULL,
102 };
103 
104 static const struct attribute_group w1_ds2780_group = {
105 	.bin_attrs = w1_ds2780_bin_attrs,
106 };
107 
108 static const struct attribute_group *w1_ds2780_groups[] = {
109 	&w1_ds2780_group,
110 	NULL,
111 };
112 
w1_ds2780_add_slave(struct w1_slave * sl)113 static int w1_ds2780_add_slave(struct w1_slave *sl)
114 {
115 	int ret;
116 	struct platform_device *pdev;
117 
118 	pdev = platform_device_alloc("ds2780-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 
w1_ds2780_remove_slave(struct w1_slave * sl)137 static void w1_ds2780_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 const struct w1_family_ops w1_ds2780_fops = {
145 	.add_slave    = w1_ds2780_add_slave,
146 	.remove_slave = w1_ds2780_remove_slave,
147 	.groups       = w1_ds2780_groups,
148 };
149 
150 static struct w1_family w1_ds2780_family = {
151 	.fid = W1_FAMILY_DS2780,
152 	.fops = &w1_ds2780_fops,
153 };
154 module_w1_family(w1_ds2780_family);
155 
156 MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
157 MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");
158 MODULE_LICENSE("GPL");
159 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2780));
160