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
 23static 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
 48int 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}
 65EXPORT_SYMBOL(w1_ds2781_io);
 66
 67int 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}
 84EXPORT_SYMBOL(w1_ds2781_eeprom_cmd);
 85
 86static ssize_t w1_slave_read(struct file *filp, struct kobject *kobj,
 87			     const 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
 95static const BIN_ATTR_RO(w1_slave, DS2781_DATA_SIZE);
 96
 97static const struct bin_attribute *const w1_ds2781_bin_attrs[] = {
 98	&bin_attr_w1_slave,
 99	NULL,
100};
101
102static const struct attribute_group w1_ds2781_group = {
103	.bin_attrs = w1_ds2781_bin_attrs,
104};
105
106static const struct attribute_group *w1_ds2781_groups[] = {
107	&w1_ds2781_group,
108	NULL,
109};
110
111static 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
129pdev_add_failed:
130	platform_device_put(pdev);
131
132	return ret;
133}
134
135static 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
142static 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
148static struct w1_family w1_ds2781_family = {
149	.fid = W1_FAMILY_DS2781,
150	.fops = &w1_ds2781_fops,
151};
152module_w1_family(w1_ds2781_family);
153
154MODULE_AUTHOR("Renata Sayakhova <renata@oktetlabs.ru>");
155MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2781 Stand-Alone Fuel Gauge IC");
156MODULE_LICENSE("GPL");
157MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2781));