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	},
176};
177
178module_platform_driver(jz4740_hwmon_driver);
179
180MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
181MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
182MODULE_LICENSE("GPL");
183MODULE_ALIAS("platform:jz4740-hwmon");
184