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
  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
  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
  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
  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
 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
 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");