aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/jz4740-hwmon.c
blob: 7d5947595b4532570051f73783b411b31aa1ad0b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/*
 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
 * JZ4740 SoC HWMON driver
 *
 * This program is free software; you can redistribute it and/or modify it
 * under  the terms of the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the License, or (at your
 * option) any later version.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>

#include <linux/completion.h>
#include <linux/mfd/core.h>

#include <linux/hwmon.h>

struct jz4740_hwmon {
	void __iomem *base;
	int irq;
	const struct mfd_cell *cell;
	struct platform_device *pdev;
	struct completion read_completion;
	struct mutex lock;
};

static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
{
	struct jz4740_hwmon *hwmon = data;

	complete(&hwmon->read_completion);
	return IRQ_HANDLED;
}

static ssize_t in0_input_show(struct device *dev,
			      struct device_attribute *dev_attr, char *buf)
{
	struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
	struct platform_device *pdev = hwmon->pdev;
	struct completion *completion = &hwmon->read_completion;
	long t;
	unsigned long val;
	int ret;

	mutex_lock(&hwmon->lock);

	reinit_completion(completion);

	enable_irq(hwmon->irq);
	hwmon->cell->enable(pdev);

	t = wait_for_completion_interruptible_timeout(completion, HZ);

	if (t > 0) {
		val = readw(hwmon->base) & 0xfff;
		val = (val * 3300) >> 12;
		ret = sprintf(buf, "%lu\n", val);
	} else {
		ret = t ? t : -ETIMEDOUT;
	}

	hwmon->cell->disable(pdev);
	disable_irq(hwmon->irq);

	mutex_unlock(&hwmon->lock);

	return ret;
}

static DEVICE_ATTR_RO(in0_input);

static struct attribute *jz4740_attrs[] = {
	&dev_attr_in0_input.attr,
	NULL
};

ATTRIBUTE_GROUPS(jz4740);

static int jz4740_hwmon_probe(struct platform_device *pdev)
{
	int ret;
	struct device *dev = &pdev->dev;
	struct jz4740_hwmon *hwmon;
	struct device *hwmon_dev;

	hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
	if (!hwmon)
		return -ENOMEM;

	hwmon->cell = mfd_get_cell(pdev);

	hwmon->irq = platform_get_irq(pdev, 0);
	if (hwmon->irq < 0) {
		dev_err(&pdev->dev, "Failed to get platform irq: %d\n",
			hwmon->irq);
		return hwmon->irq;
	}

	hwmon->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(hwmon->base))
		return PTR_ERR(hwmon->base);

	hwmon->pdev = pdev;
	init_completion(&hwmon->read_completion);
	mutex_init(&hwmon->lock);

	ret = devm_request_irq(dev, hwmon->irq, jz4740_hwmon_irq, 0,
			       pdev->name, hwmon);
	if (ret) {
		dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
		return ret;
	}
	disable_irq(hwmon->irq);

	hwmon_dev = devm_hwmon_device_register_with_groups(dev, "jz4740", hwmon,
							   jz4740_groups);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static struct platform_driver jz4740_hwmon_driver = {
	.probe	= jz4740_hwmon_probe,
	.driver = {
		.name = "jz4740-hwmon",
	},
};

module_platform_driver(jz4740_hwmon_driver);

MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:jz4740-hwmon");