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         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
  44 static 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
  50 static 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
  58 static 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         reinit_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
  92 static DEVICE_ATTR(name, S_IRUGO, jz4740_hwmon_show_name, NULL);
  93 static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
  94
  95 static struct attribute *jz4740_hwmon_attributes[] = {
  96         &dev_attr_name.attr,
  97         &dev_attr_in0_input.attr,
  98         NULL
  99 };
 100
 101 static const struct attribute_group jz4740_hwmon_attr_group = {
 102         .attrs = jz4740_hwmon_attributes,
 103 };
 104
 105 static int 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
 170 err_remove_file:
 171         sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
 172         return ret;
 173 }
 174
 175 static int 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
 185 static struct platform_driver jz4740_hwmon_driver = {
 186         .probe  = jz4740_hwmon_probe,
 187         .remove = jz4740_hwmon_remove,
 188         .driver = {
 189                 .name = "jz4740-hwmon",
 190                 .owner = THIS_MODULE,
 191         },
 192 };
 193
 194 module_platform_driver(jz4740_hwmon_driver);
 195
 196 MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
 197 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 198 MODULE_LICENSE("GPL");
 199 MODULE_ALIAS("platform:jz4740-hwmon");