tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 struct resource *mem;
32 void __iomem *base;
33
34 int irq;
35
36 const struct mfd_cell *cell;
37 struct device *hwmon;
38
39 struct completion read_completion;
40
41 struct mutex lock;
42};
43
44static ssize_t jz4740_hwmon_show_name(struct device *dev,
45 struct device_attribute *dev_attr, char *buf)
46{
47 return sprintf(buf, "jz4740\n");
48}
49
50static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
51{
52 struct jz4740_hwmon *hwmon = data;
53
54 complete(&hwmon->read_completion);
55 return IRQ_HANDLED;
56}
57
58static ssize_t jz4740_hwmon_read_adcin(struct device *dev,
59 struct device_attribute *dev_attr, char *buf)
60{
61 struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
62 struct completion *completion = &hwmon->read_completion;
63 long t;
64 unsigned long val;
65 int ret;
66
67 mutex_lock(&hwmon->lock);
68
69 INIT_COMPLETION(*completion);
70
71 enable_irq(hwmon->irq);
72 hwmon->cell->enable(to_platform_device(dev));
73
74 t = wait_for_completion_interruptible_timeout(completion, HZ);
75
76 if (t > 0) {
77 val = readw(hwmon->base) & 0xfff;
78 val = (val * 3300) >> 12;
79 ret = sprintf(buf, "%lu\n", val);
80 } else {
81 ret = t ? t : -ETIMEDOUT;
82 }
83
84 hwmon->cell->disable(to_platform_device(dev));
85 disable_irq(hwmon->irq);
86
87 mutex_unlock(&hwmon->lock);
88
89 return ret;
90}
91
92static DEVICE_ATTR(name, S_IRUGO, jz4740_hwmon_show_name, NULL);
93static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
94
95static struct attribute *jz4740_hwmon_attributes[] = {
96 &dev_attr_name.attr,
97 &dev_attr_in0_input.attr,
98 NULL
99};
100
101static const struct attribute_group jz4740_hwmon_attr_group = {
102 .attrs = jz4740_hwmon_attributes,
103};
104
105static int __devinit jz4740_hwmon_probe(struct platform_device *pdev)
106{
107 int ret;
108 struct jz4740_hwmon *hwmon;
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 hwmon->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
124 if (!hwmon->mem) {
125 dev_err(&pdev->dev, "Failed to get platform mmio resource\n");
126 return -ENOENT;
127 }
128
129 hwmon->mem = devm_request_mem_region(&pdev->dev, hwmon->mem->start,
130 resource_size(hwmon->mem), pdev->name);
131 if (!hwmon->mem) {
132 dev_err(&pdev->dev, "Failed to request mmio memory region\n");
133 return -EBUSY;
134 }
135
136 hwmon->base = devm_ioremap_nocache(&pdev->dev, hwmon->mem->start,
137 resource_size(hwmon->mem));
138 if (!hwmon->base) {
139 dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
140 return -EBUSY;
141 }
142
143 init_completion(&hwmon->read_completion);
144 mutex_init(&hwmon->lock);
145
146 platform_set_drvdata(pdev, hwmon);
147
148 ret = devm_request_irq(&pdev->dev, hwmon->irq, jz4740_hwmon_irq, 0,
149 pdev->name, hwmon);
150 if (ret) {
151 dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
152 return ret;
153 }
154 disable_irq(hwmon->irq);
155
156 ret = sysfs_create_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
157 if (ret) {
158 dev_err(&pdev->dev, "Failed to create sysfs group: %d\n", ret);
159 return ret;
160 }
161
162 hwmon->hwmon = hwmon_device_register(&pdev->dev);
163 if (IS_ERR(hwmon->hwmon)) {
164 ret = PTR_ERR(hwmon->hwmon);
165 goto err_remove_file;
166 }
167
168 return 0;
169
170err_remove_file:
171 sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
172 return ret;
173}
174
175static int __devexit jz4740_hwmon_remove(struct platform_device *pdev)
176{
177 struct jz4740_hwmon *hwmon = platform_get_drvdata(pdev);
178
179 hwmon_device_unregister(hwmon->hwmon);
180 sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
181
182 return 0;
183}
184
185static struct platform_driver jz4740_hwmon_driver = {
186 .probe = jz4740_hwmon_probe,
187 .remove = __devexit_p(jz4740_hwmon_remove),
188 .driver = {
189 .name = "jz4740-hwmon",
190 .owner = THIS_MODULE,
191 },
192};
193
194module_platform_driver(jz4740_hwmon_driver);
195
196MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
197MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
198MODULE_LICENSE("GPL");
199MODULE_ALIAS("platform:jz4740-hwmon");