w1: add Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC support

Add support for the Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC.

It was suggested to combine this functionality with the current ds2782
driver.  Unfortunately, I'm unable to commit the time to refactoring this
driver to that extent and I don't have a platform with the ds2782 part to
validate that there are no regression issues by adding this functionality.

[akpm@linux-foundation.org: use min_t()]
Signed-off-by: Clifton Barnes <cabarnes@indesign-llc.com>
Tested-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 217 insertions, 0 deletions

diff --git a/drivers/w1/slaves/w1_ds2780.c b/drivers/w1/slaves/w1_ds2780.c
new file mode 100644
index 000000000000..274c8f38303f
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds2780.c
@@ -0,0 +1,217 @@
+/*
+ * 1-Wire implementation for the ds2780 chip
+ *
+ * Copyright (C) 2010 Indesign, LLC
+ *
+ * Author: Clifton Barnes <cabarnes@indesign-llc.com>
+ *
+ * Based on w1-ds2760 driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/idr.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+#include "w1_ds2780.h"
+
+int w1_ds2780_io(struct device *dev, char *buf, int addr, size_t count,
+			int io)
+{
+	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
+
+	if (!dev)
+		return -ENODEV;
+
+	mutex_lock(&sl->master->mutex);
+
+	if (addr > DS2780_DATA_SIZE || addr < 0) {
+		count = 0;
+		goto out;
+	}
+	count = min_t(int, count, DS2780_DATA_SIZE - addr);
+
+	if (w1_reset_select_slave(sl) == 0) {
+		if (io) {
+			w1_write_8(sl->master, W1_DS2780_WRITE_DATA);
+			w1_write_8(sl->master, addr);
+			w1_write_block(sl->master, buf, count);
+			/* XXX w1_write_block returns void, not n_written */
+		} else {
+			w1_write_8(sl->master, W1_DS2780_READ_DATA);
+			w1_write_8(sl->master, addr);
+			count = w1_read_block(sl->master, buf, count);
+		}
+	}
+
+out:
+	mutex_unlock(&sl->master->mutex);
+
+	return count;
+}
+EXPORT_SYMBOL(w1_ds2780_io);
+
+int w1_ds2780_eeprom_cmd(struct device *dev, int addr, int cmd)
+{
+	struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
+
+	if (!dev)
+		return -EINVAL;
+
+	mutex_lock(&sl->master->mutex);
+
+	if (w1_reset_select_slave(sl) == 0) {
+		w1_write_8(sl->master, cmd);
+		w1_write_8(sl->master, addr);
+	}
+
+	mutex_unlock(&sl->master->mutex);
+	return 0;
+}
+EXPORT_SYMBOL(w1_ds2780_eeprom_cmd);
+
+static ssize_t w1_ds2780_read_bin(struct file *filp,
+				  struct kobject *kobj,
+				  struct bin_attribute *bin_attr,
+				  char *buf, loff_t off, size_t count)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	return w1_ds2780_io(dev, buf, off, count, 0);
+}
+
+static struct bin_attribute w1_ds2780_bin_attr = {
+	.attr = {
+		.name = "w1_slave",
+		.mode = S_IRUGO,
+	},
+	.size = DS2780_DATA_SIZE,
+	.read = w1_ds2780_read_bin,
+};
+
+static DEFINE_IDR(bat_idr);
+static DEFINE_MUTEX(bat_idr_lock);
+
+static int new_bat_id(void)
+{
+	int ret;
+
+	while (1) {
+		int id;
+
+		ret = idr_pre_get(&bat_idr, GFP_KERNEL);
+		if (ret == 0)
+			return -ENOMEM;
+
+		mutex_lock(&bat_idr_lock);
+		ret = idr_get_new(&bat_idr, NULL, &id);
+		mutex_unlock(&bat_idr_lock);
+
+		if (ret == 0) {
+			ret = id & MAX_ID_MASK;
+			break;
+		} else if (ret == -EAGAIN) {
+			continue;
+		} else {
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static void release_bat_id(int id)
+{
+	mutex_lock(&bat_idr_lock);
+	idr_remove(&bat_idr, id);
+	mutex_unlock(&bat_idr_lock);
+}
+
+static int w1_ds2780_add_slave(struct w1_slave *sl)
+{
+	int ret;
+	int id;
+	struct platform_device *pdev;
+
+	id = new_bat_id();
+	if (id < 0) {
+		ret = id;
+		goto noid;
+	}
+
+	pdev = platform_device_alloc("ds2780-battery", id);
+	if (!pdev) {
+		ret = -ENOMEM;
+		goto pdev_alloc_failed;
+	}
+	pdev->dev.parent = &sl->dev;
+
+	ret = platform_device_add(pdev);
+	if (ret)
+		goto pdev_add_failed;
+
+	ret = sysfs_create_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
+	if (ret)
+		goto bin_attr_failed;
+
+	dev_set_drvdata(&sl->dev, pdev);
+
+	return 0;
+
+bin_attr_failed:
+pdev_add_failed:
+	platform_device_unregister(pdev);
+pdev_alloc_failed:
+	release_bat_id(id);
+noid:
+	return ret;
+}
+
+static void w1_ds2780_remove_slave(struct w1_slave *sl)
+{
+	struct platform_device *pdev = dev_get_drvdata(&sl->dev);
+	int id = pdev->id;
+
+	platform_device_unregister(pdev);
+	release_bat_id(id);
+	sysfs_remove_bin_file(&sl->dev.kobj, &w1_ds2780_bin_attr);
+}
+
+static struct w1_family_ops w1_ds2780_fops = {
+	.add_slave    = w1_ds2780_add_slave,
+	.remove_slave = w1_ds2780_remove_slave,
+};
+
+static struct w1_family w1_ds2780_family = {
+	.fid = W1_FAMILY_DS2780,
+	.fops = &w1_ds2780_fops,
+};
+
+static int __init w1_ds2780_init(void)
+{
+	idr_init(&bat_idr);
+	return w1_register_family(&w1_ds2780_family);
+}
+
+static void __exit w1_ds2780_exit(void)
+{
+	w1_unregister_family(&w1_ds2780_family);
+	idr_destroy(&bat_idr);
+}
+
+module_init(w1_ds2780_init);
+module_exit(w1_ds2780_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Clifton Barnes <cabarnes@indesign-llc.com>");
+MODULE_DESCRIPTION("1-wire Driver for Maxim/Dallas DS2780 Stand-Alone Fuel Gauge IC");