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
30 struct 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
jz4740_hwmon_show_name(struct device * dev,struct device_attribute * dev_attr,char * buf)43 static 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
jz4740_hwmon_irq(int irq,void * data)49 static 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
jz4740_hwmon_read_adcin(struct device * dev,struct device_attribute * dev_attr,char * buf)57 static 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
91 static DEVICE_ATTR(name, S_IRUGO, jz4740_hwmon_show_name, NULL);
92 static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
93
94 static struct attribute *jz4740_hwmon_attributes[] = {
95 &dev_attr_name.attr,
96 &dev_attr_in0_input.attr,
97 NULL
98 };
99
100 static const struct attribute_group jz4740_hwmon_attr_group = {
101 .attrs = jz4740_hwmon_attributes,
102 };
103
jz4740_hwmon_probe(struct platform_device * pdev)104 static 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
155 err_remove_file:
156 sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
157 return ret;
158 }
159
jz4740_hwmon_remove(struct platform_device * pdev)160 static 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
170 static 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
178 module_platform_driver(jz4740_hwmon_driver);
179
180 MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
181 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
182 MODULE_LICENSE("GPL");
183 MODULE_ALIAS("platform:jz4740-hwmon");
184