/drivers/w1/slaves/w1_ds2780.c

  1/*
  2 * 1-Wire implementation for the ds2780 chip
  3 *
  4 * Copyright (C) 2010 Indesign, LLC
  5 *
  6 * Author: Clifton Barnes <cabarnes@indesign-llc.com>
  7 *
  8 * Based on w1-ds2760 driver
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License version 2 as
 12 * published by the Free Software Foundation.
 13 *
 14 */
 15
 16#include <linux/kernel.h>
 17#include <linux/module.h>
 18#include <linux/device.h>
 19#include <linux/types.h>
 20#include <linux/platform_device.h>
 21#include <linux/mutex.h>
 22#include <linux/idr.h>
 23
 24#include "../w1.h"
 25#include "../w1_int.h"
 26#include "../w1_family.h"
 27#include "w1_ds2780.h"
 28
 29static int w1_ds2780_do_io(struct device *dev, char *buf, int addr,
 30			size_t count, int io)
 31{
 32	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 33
 34	if (addr > DS2780_DATA_SIZE || addr < 0)
 35		return 0;
 36
 37	count = min_t(int, count, DS2780_DATA_SIZE - addr);
 38
 39	if (w1_reset_select_slave(sl) == 0) {
 40		if (io) {
 41			w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
 42			w1_write_8(sl->master, addr);
 43			w1_write_block(sl->master, buf, count);
 44		} else {
 45			w1_write_8(sl->master, W1_DS2780_READ_DATA);
 46			w1_write_8(sl->master, addr);
 47			count = w1_read_block(sl->master, buf, count);
 48		}
 49	}
 50
 51	return count;
 52}
 53
 54int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
 55			int io)
 56{
 57	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 58	int ret;
 59
 60	if (!dev)
 61		return -ENODEV;
 62
 63	mutex_lock(&sl->master->mutex);
 64
 65	ret = w1_ds2780_do_io(dev, buf, addr, count, io);
 66
 67	mutex_unlock(&sl->master->mutex);
 68
 69	return ret;
 70}
 71EXPORT_SYMBOL(w1_ds2780_io);
 72
 73int w1_ds2780_io_nolock(struct device *dev, char *buf, int addr, size_t count,
 74			int io)
 75{
 76	int ret;
 77
 78	if (!dev)
 79		return -ENODEV;
 80
 81	ret = w1_ds2780_do_io(dev, buf, addr, count, io);
 82
 83	return ret;
 84}
 85EXPORT_SYMBOL(w1_ds2780_io_nolock);
 86
 87int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
 88{
 89	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 90
 91	if (!dev)
 92		return -EINVAL;
 93
 94	mutex_lock(&sl->master->mutex);
 95
 96	if (w1_reset_select_slave(sl) == 0) {
 97		w1_write_8(sl->master, cmd);
 98		w1_write_8(sl->master, addr);
 99	}
100
101	mutex_unlock(&sl->master->mutex);
102	return 0;
103}
104EXPORT_SYMBOL(w1_ds2780_eeprom_cmd);
105
106static ssize_t w1_ds2780_read_bin(struct file *filp,
107				  struct kobject *kobj,
108				  struct bin_attribute *bin_attr,
109				  char *buf, loff_t off, size_t count)
110{
111	struct device *dev = container_of(kobj, struct device, kobj);
112	return w1_ds2780_io(dev, buf, off, count, 0);
113}
114
115static struct bin_attribute w1_ds2780_bin_attr = {
116	.attr = {
117		.name = "w1_slave",
118		.mode = S_IRUGO,
119	},
120	.size = DS2780_DATA_SIZE,
121	.read = w1_ds2780_read_bin,
122};
123
124static DEFINE_IDR(bat_idr);
125static DEFINE_MUTEX(bat_idr_lock);
126
127static int new_bat_id(void)
128{
129	int ret;
130
131	while (1) {
132		int id;
133
134		ret = idr_pre_get(&bat_idr, GFP_KERNEL);
135		if (ret == 0)
136			return -ENOMEM;
137
138		mutex_lock(&bat_idr_lock);
139		ret = idr_get_new(&bat_idr, NULL, &id);
140		mutex_unlock(&bat_idr_lock);
141
142		if (ret == 0) {
143			ret = id & MAX_ID_MASK;
144			break;
145		} else if (ret == -EAGAIN) {
146			continue;
147		} else {
148			break;
149		}
150	}
151
152	return ret;
153}
154
155static void release_bat_id(int id)
156{
157	mutex_lock(&bat_idr_lock);
158	idr_remove(&bat_idr, id);
159	mutex_unlock(&bat_idr_lock);
160}
161
162static int w1_ds2780_add_slave(struct w1_slave *sl)
163{
164	int ret;
165	int id;
166	struct platform_device *pdev;
167
168	id = new_bat_id();
169	if (id < 0) {
170		ret = id;
171		goto noid;
172	}
173
174	pdev = platform_device_alloc("ds2780-battery", id);
175	if (!pdev) {
176		ret = -ENOMEM;
177		goto pdev_alloc_failed;
178	}
179	pdev->dev.parent = &sl->dev;
180
181	ret = platform_device_add(pdev);
182	if (ret)
183		goto pdev_add_failed;
184
185	ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
186	if (ret)
187		goto bin_attr_failed;
188
189	dev_set_drvdata(&sl->dev, pdev);
190
191	return 0;
192
193bin_attr_failed:
194pdev_add_failed:
195	platform_device_unregister(pdev);
196pdev_alloc_failed:
197	release_bat_id(id);
198noid:
199	return ret;
200}
201
202static void w1_ds2780_remove_slave(struct w1_slave *sl)
203{
204	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
205	int id = pdev->id;
206
207	platform_device_unregister(pdev);
208	release_bat_id(id);
209	sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
210}
211
212static struct w1_family_ops w1_ds2780_fops = {
213	.add_slave    = w1_ds2780_add_slave,
214	.remove_slave = w1_ds2780_remove_slave,
215};
216
217static struct w1_family w1_ds2780_family = {
218	.fid = W1_FAMILY_DS2780,
219	.fops = &w1_ds2780_fops,
220};
221
222static int __init w1_ds2780_init(void)
223{
224	idr_init(&bat_idr);
225	return w1_register_family(&w1_ds2780_family);
226}
227
228static void __exit w1_ds2780_exit(void)
229{
230	w1_unregister_family(&w1_ds2780_family);
231	idr_destroy(&bat_idr);
232}
233
234module_init(w1_ds2780_init);
235module_exit(w1_ds2780_exit);
236
237MODULE_LICENSE("GPL");
238MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
239MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");