drivers/hwmon/jz4740-hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
   4  * JZ4740 SoC HWMON driver
   5  */
   6
   7 #include <linux/err.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15
  16 #include <linux/completion.h>
  17 #include <linux/mfd/core.h>
  18
  19 #include <linux/hwmon.h>
  20
  21 struct jz4740_hwmon {
  22         void __iomem *base;
  23         int irq;
  24         const struct mfd_cell *cell;
  25         struct platform_device *pdev;
  26         struct completion read_completion;
  27         struct mutex lock;
  28 };
  29
  30 static irqreturn_t jz4740_hwmon_irq(int irq, void *data)
  31 {
  32         struct jz4740_hwmon *hwmon = data;
  33
  34         complete(&hwmon->read_completion);
  35         return IRQ_HANDLED;
  36 }
  37
  38 static ssize_t in0_input_show(struct device *dev,
  39                               struct device_attribute *dev_attr, char *buf)
  40 {
  41         struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
  42         struct platform_device *pdev = hwmon->pdev;
  43         struct completion *completion = &hwmon->read_completion;
  44         long t;
  45         unsigned long val;
  46         int ret;
  47
  48         mutex_lock(&hwmon->lock);
  49
  50         reinit_completion(completion);
  51
  52         enable_irq(hwmon->irq);
  53         hwmon->cell->enable(pdev);
  54
  55         t = wait_for_completion_interruptible_timeout(completion, HZ);
  56
  57         if (t > 0) {
  58                 val = readw(hwmon->base) & 0xfff;
  59                 val = (val * 3300) >> 12;
  60                 ret = sprintf(buf, "%lu\n", val);
  61         } else {
  62                 ret = t ? t : -ETIMEDOUT;
  63         }
  64
  65         hwmon->cell->disable(pdev);
  66         disable_irq(hwmon->irq);
  67
  68         mutex_unlock(&hwmon->lock);
  69
  70         return ret;
  71 }
  72
  73 static DEVICE_ATTR_RO(in0_input);
  74
  75 static struct attribute *jz4740_attrs[] = {
  76         &dev_attr_in0_input.attr,
  77         NULL
  78 };
  79
  80 ATTRIBUTE_GROUPS(jz4740);
  81
  82 static int jz4740_hwmon_probe(struct platform_device *pdev)
  83 {
  84         int ret;
  85         struct device *dev = &pdev->dev;
  86         struct jz4740_hwmon *hwmon;
  87         struct device *hwmon_dev;
  88
  89         hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
  90         if (!hwmon)
  91                 return -ENOMEM;
  92
  93         hwmon->cell = mfd_get_cell(pdev);
  94
  95         hwmon->irq = platform_get_irq(pdev, 0);
  96         if (hwmon->irq < 0) {
  97                 dev_err(&pdev->dev, "Failed to get platform irq: %d\n",
  98                         hwmon->irq);
  99                 return hwmon->irq;
 100         }
 101
 102         hwmon->base = devm_platform_ioremap_resource(pdev, 0);
 103         if (IS_ERR(hwmon->base))
 104                 return PTR_ERR(hwmon->base);
 105
 106         hwmon->pdev = pdev;
 107         init_completion(&hwmon->read_completion);
 108         mutex_init(&hwmon->lock);
 109
 110         ret = devm_request_irq(dev, hwmon->irq, jz4740_hwmon_irq, 0,
 111                                pdev->name, hwmon);
 112         if (ret) {
 113                 dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
 114                 return ret;
 115         }
 116         disable_irq(hwmon->irq);
 117
 118         hwmon_dev = devm_hwmon_device_register_with_groups(dev, "jz4740", hwmon,
 119                                                            jz4740_groups);
 120         return PTR_ERR_OR_ZERO(hwmon_dev);
 121 }
 122
 123 static struct platform_driver jz4740_hwmon_driver = {
 124         .probe  = jz4740_hwmon_probe,
 125         .driver = {
 126                 .name = "jz4740-hwmon",
 127         },
 128 };
 129
 130 module_platform_driver(jz4740_hwmon_driver);
 131
 132 MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
 133 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 134 MODULE_LICENSE("GPL");
 135 MODULE_ALIAS("platform:jz4740-hwmon");