1/*
  2 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
  3 * JZ4740 SoC HWMON driver
  4 *
  5 * This program is free software; you can redistribute it and/or modify it
  6 * under  the terms of the GNU General  Public License as published by the
  7 * Free Software Foundation;  either version 2 of the License, or (at your
  8 * option) any later version.
  9 *
 10 * You should have received a copy of the GNU General Public License along
 11 * with this program; if not, write to the Free Software Foundation, Inc.,
 12 * 675 Mass Ave, Cambridge, MA 02139, USA.
 13 *
 14 */
 15
 16#include <linux/err.h>
 17#include <linux/interrupt.h>
 18#include <linux/kernel.h>
 19#include <linux/module.h>
 20#include <linux/mutex.h>
 21#include <linux/platform_device.h>
 22#include <linux/slab.h>
 23#include <linux/io.h>
 24
 25#include <linux/completion.h>
 26#include <linux/mfd/core.h>
 27
 28#include <linux/hwmon.h>
 29
 30struct jz4740_hwmon {
 31	void __iomem *base;
 32
 33	int irq;
 34
 35	const struct mfd_cell *cell;
 36	struct device *hwmon;
 37
 38	struct completion read_completion;
 39
 40	struct mutex lock;
 41};
 42
 43static ssize_t jz4740_hwmon_show_name(struct device *dev,
 44	struct device_attribute *dev_attr, char *buf)
 45{
 46	return sprintf(buf, "jz4740\n");
 47}
 48
 49static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
 50{
 51	struct jz4740_hwmon *hwmon = data;
 52
 53	complete(&hwmon->read_completion);
 54	return IRQ_HANDLED;
 55}
 56
 57static ssize_t jz4740_hwmon_read_adcin(struct device *dev,
 58	struct device_attribute *dev_attr, char *buf)
 59{
 60	struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
 61	struct completion *completion = &hwmon->read_completion;
 62	long t;
 63	unsigned long val;
 64	int ret;
 65
 66	mutex_lock(&hwmon->lock);
 67
 68	reinit_completion(completion);
 69
 70	enable_irq(hwmon->irq);
 71	hwmon->cell->enable(to_platform_device(dev));
 72
 73	t = wait_for_completion_interruptible_timeout(completion, HZ);
 74
 75	if (t > 0) {
 76		val = readw(hwmon->base) & 0xfff;
 77		val = (val * 3300) >> 12;
 78		ret = sprintf(buf, "%lu\n", val);
 79	} else {
 80		ret = t ? t : -ETIMEDOUT;
 81	}
 82
 83	hwmon->cell->disable(to_platform_device(dev));
 84	disable_irq(hwmon->irq);
 85
 86	mutex_unlock(&hwmon->lock);
 87
 88	return ret;
 89}
 90
 91static DEVICE_ATTR(name, S_IRUGO, jz4740_hwmon_show_name, NULL);
 92static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
 93
 94static struct attribute *jz4740_hwmon_attributes[] = {
 95	&dev_attr_name.attr,
 96	&dev_attr_in0_input.attr,
 97	NULL
 98};
 99
100static const struct attribute_group jz4740_hwmon_attr_group = {
101	.attrs = jz4740_hwmon_attributes,
102};
103
104static int jz4740_hwmon_probe(struct platform_device *pdev)
105{
106	int ret;
107	struct jz4740_hwmon *hwmon;
108	struct resource *mem;
109
110	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
111	if (!hwmon)
112		return -ENOMEM;
113
114	hwmon->cell = mfd_get_cell(pdev);
115
116	hwmon->irq = platform_get_irq(pdev, 0);
117	if (hwmon->irq < 0) {
118		dev_err(&pdev->dev, "Failed to get platform irq: %d\n",
119			hwmon->irq);
120		return hwmon->irq;
121	}
122
123	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
124	hwmon->base = devm_ioremap_resource(&pdev->dev, mem);
125	if (IS_ERR(hwmon->base))
126		return PTR_ERR(hwmon->base);
127
128	init_completion(&hwmon->read_completion);
129	mutex_init(&hwmon->lock);
130
131	platform_set_drvdata(pdev, hwmon);
132
133	ret = devm_request_irq(&pdev->dev, hwmon->irq, jz4740_hwmon_irq, 0,
134			       pdev->name, hwmon);
135	if (ret) {
136		dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
137		return ret;
138	}
139	disable_irq(hwmon->irq);
140
141	ret = sysfs_create_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
142	if (ret) {
143		dev_err(&pdev->dev, "Failed to create sysfs group: %d\n", ret);
144		return ret;
145	}
146
147	hwmon->hwmon = hwmon_device_register(&pdev->dev);
148	if (IS_ERR(hwmon->hwmon)) {
149		ret = PTR_ERR(hwmon->hwmon);
150		goto err_remove_file;
151	}
152
153	return 0;
154
155err_remove_file:
156	sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
157	return ret;
158}
159
160static int jz4740_hwmon_remove(struct platform_device *pdev)
161{
162	struct jz4740_hwmon *hwmon = platform_get_drvdata(pdev);
163
164	hwmon_device_unregister(hwmon->hwmon);
165	sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
166
167	return 0;
168}
169
170static struct platform_driver jz4740_hwmon_driver = {
171	.probe	= jz4740_hwmon_probe,
172	.remove = jz4740_hwmon_remove,
173	.driver = {
174		.name = "jz4740-hwmon",
175		.owner = THIS_MODULE,
176	},
177};
178
179module_platform_driver(jz4740_hwmon_driver);
180
181MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
182MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
183MODULE_LICENSE("GPL");
184MODULE_ALIAS("platform:jz4740-hwmon");