linux/drivers/hwmon/jz4740-hwmon.c
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   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
  24#include <linux/completion.h>
  25#include <linux/mfd/core.h>
  26
  27#include <linux/hwmon.h>
  28
  29struct jz4740_hwmon {
  30        struct resource *mem;
  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
  43static 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
  49static 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
  57static 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        INIT_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
  91static DEVICE_ATTR(name, S_IRUGO, jz4740_hwmon_show_name, NULL);
  92static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
  93
  94static struct attribute *jz4740_hwmon_attributes[] = {
  95        &dev_attr_name.attr,
  96        &dev_attr_in0_input.attr,
  97        NULL
  98};
  99
 100static const struct attribute_group jz4740_hwmon_attr_group = {
 101        .attrs = jz4740_hwmon_attributes,
 102};
 103
 104static int __devinit jz4740_hwmon_probe(struct platform_device *pdev)
 105{
 106        int ret;
 107        struct jz4740_hwmon *hwmon;
 108
 109        hwmon = kmalloc(sizeof(*hwmon), GFP_KERNEL);
 110        if (!hwmon) {
 111                dev_err(&pdev->dev, "Failed to allocate driver structure\n");
 112                return -ENOMEM;
 113        }
 114
 115        hwmon->cell = mfd_get_cell(pdev);
 116
 117        hwmon->irq = platform_get_irq(pdev, 0);
 118        if (hwmon->irq < 0) {
 119                ret = hwmon->irq;
 120                dev_err(&pdev->dev, "Failed to get platform irq: %d\n", ret);
 121                goto err_free;
 122        }
 123
 124        hwmon->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 125        if (!hwmon->mem) {
 126                ret = -ENOENT;
 127                dev_err(&pdev->dev, "Failed to get platform mmio resource\n");
 128                goto err_free;
 129        }
 130
 131        hwmon->mem = request_mem_region(hwmon->mem->start,
 132                        resource_size(hwmon->mem), pdev->name);
 133        if (!hwmon->mem) {
 134                ret = -EBUSY;
 135                dev_err(&pdev->dev, "Failed to request mmio memory region\n");
 136                goto err_free;
 137        }
 138
 139        hwmon->base = ioremap_nocache(hwmon->mem->start,
 140                        resource_size(hwmon->mem));
 141        if (!hwmon->base) {
 142                ret = -EBUSY;
 143                dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
 144                goto err_release_mem_region;
 145        }
 146
 147        init_completion(&hwmon->read_completion);
 148        mutex_init(&hwmon->lock);
 149
 150        platform_set_drvdata(pdev, hwmon);
 151
 152        ret = request_irq(hwmon->irq, jz4740_hwmon_irq, 0, pdev->name, hwmon);
 153        if (ret) {
 154                dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
 155                goto err_iounmap;
 156        }
 157        disable_irq(hwmon->irq);
 158
 159        ret = sysfs_create_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
 160        if (ret) {
 161                dev_err(&pdev->dev, "Failed to create sysfs group: %d\n", ret);
 162                goto err_free_irq;
 163        }
 164
 165        hwmon->hwmon = hwmon_device_register(&pdev->dev);
 166        if (IS_ERR(hwmon->hwmon)) {
 167                ret = PTR_ERR(hwmon->hwmon);
 168                goto err_remove_file;
 169        }
 170
 171        return 0;
 172
 173err_remove_file:
 174        sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
 175err_free_irq:
 176        free_irq(hwmon->irq, hwmon);
 177err_iounmap:
 178        platform_set_drvdata(pdev, NULL);
 179        iounmap(hwmon->base);
 180err_release_mem_region:
 181        release_mem_region(hwmon->mem->start, resource_size(hwmon->mem));
 182err_free:
 183        kfree(hwmon);
 184
 185        return ret;
 186}
 187
 188static int __devexit jz4740_hwmon_remove(struct platform_device *pdev)
 189{
 190        struct jz4740_hwmon *hwmon = platform_get_drvdata(pdev);
 191
 192        hwmon_device_unregister(hwmon->hwmon);
 193        sysfs_remove_group(&pdev->dev.kobj, &jz4740_hwmon_attr_group);
 194
 195        free_irq(hwmon->irq, hwmon);
 196
 197        iounmap(hwmon->base);
 198        release_mem_region(hwmon->mem->start, resource_size(hwmon->mem));
 199
 200        platform_set_drvdata(pdev, NULL);
 201        kfree(hwmon);
 202
 203        return 0;
 204}
 205
 206static struct platform_driver jz4740_hwmon_driver = {
 207        .probe  = jz4740_hwmon_probe,
 208        .remove = __devexit_p(jz4740_hwmon_remove),
 209        .driver = {
 210                .name = "jz4740-hwmon",
 211                .owner = THIS_MODULE,
 212        },
 213};
 214
 215module_platform_driver(jz4740_hwmon_driver);
 216
 217MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
 218MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 219MODULE_LICENSE("GPL");
 220MODULE_ALIAS("platform:jz4740-hwmon");
 221
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