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Linux/drivers/hwmon/jz4740-hwmon.c

  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         int irq;
 33         const struct mfd_cell *cell;
 34         struct platform_device *pdev;
 35         struct completion read_completion;
 36         struct mutex lock;
 37 };
 38 
 39 static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
 40 {
 41         struct jz4740_hwmon *hwmon = data;
 42 
 43         complete(&hwmon->read_completion);
 44         return IRQ_HANDLED;
 45 }
 46 
 47 static ssize_t jz4740_hwmon_read_adcin(struct device *dev,
 48         struct device_attribute *dev_attr, char *buf)
 49 {
 50         struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
 51         struct platform_device *pdev = hwmon->pdev;
 52         struct completion *completion = &hwmon->read_completion;
 53         long t;
 54         unsigned long val;
 55         int ret;
 56 
 57         mutex_lock(&hwmon->lock);
 58 
 59         reinit_completion(completion);
 60 
 61         enable_irq(hwmon->irq);
 62         hwmon->cell->enable(pdev);
 63 
 64         t = wait_for_completion_interruptible_timeout(completion, HZ);
 65 
 66         if (t > 0) {
 67                 val = readw(hwmon->base) & 0xfff;
 68                 val = (val * 3300) >> 12;
 69                 ret = sprintf(buf, "%lu\n", val);
 70         } else {
 71                 ret = t ? t : -ETIMEDOUT;
 72         }
 73 
 74         hwmon->cell->disable(pdev);
 75         disable_irq(hwmon->irq);
 76 
 77         mutex_unlock(&hwmon->lock);
 78 
 79         return ret;
 80 }
 81 
 82 static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
 83 
 84 static struct attribute *jz4740_attrs[] = {
 85         &dev_attr_in0_input.attr,
 86         NULL
 87 };
 88 
 89 ATTRIBUTE_GROUPS(jz4740);
 90 
 91 static int jz4740_hwmon_probe(struct platform_device *pdev)
 92 {
 93         int ret;
 94         struct device *dev = &pdev->dev;
 95         struct jz4740_hwmon *hwmon;
 96         struct device *hwmon_dev;
 97         struct resource *mem;
 98 
 99         hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
100         if (!hwmon)
101                 return -ENOMEM;
102 
103         hwmon->cell = mfd_get_cell(pdev);
104 
105         hwmon->irq = platform_get_irq(pdev, 0);
106         if (hwmon->irq < 0) {
107                 dev_err(&pdev->dev, "Failed to get platform irq: %d\n",
108                         hwmon->irq);
109                 return hwmon->irq;
110         }
111 
112         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
113         hwmon->base = devm_ioremap_resource(&pdev->dev, mem);
114         if (IS_ERR(hwmon->base))
115                 return PTR_ERR(hwmon->base);
116 
117         hwmon->pdev = pdev;
118         init_completion(&hwmon->read_completion);
119         mutex_init(&hwmon->lock);
120 
121         ret = devm_request_irq(dev, hwmon->irq, jz4740_hwmon_irq, 0,
122                                pdev->name, hwmon);
123         if (ret) {
124                 dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
125                 return ret;
126         }
127         disable_irq(hwmon->irq);
128 
129         hwmon_dev = devm_hwmon_device_register_with_groups(dev, "jz4740", hwmon,
130                                                            jz4740_groups);
131         return PTR_ERR_OR_ZERO(hwmon_dev);
132 }
133 
134 static struct platform_driver jz4740_hwmon_driver = {
135         .probe  = jz4740_hwmon_probe,
136         .driver = {
137                 .name = "jz4740-hwmon",
138         },
139 };
140 
141 module_platform_driver(jz4740_hwmon_driver);
142 
143 MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
144 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
145 MODULE_LICENSE("GPL");
146 MODULE_ALIAS("platform:jz4740-hwmon");
147 

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