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
 30struct 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
 39static 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
 47static 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
 82static DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL);
 83
 84static struct attribute *jz4740_attrs[] = {
 85	&dev_attr_in0_input.attr,
 86	NULL
 87};
 88
 89ATTRIBUTE_GROUPS(jz4740);
 90
 91static 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
134static struct platform_driver jz4740_hwmon_driver = {
135	.probe	= jz4740_hwmon_probe,
136	.driver = {
137		.name = "jz4740-hwmon",
138	},
139};
140
141module_platform_driver(jz4740_hwmon_driver);
142
143MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
144MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
145MODULE_LICENSE("GPL");
146MODULE_ALIAS("platform:jz4740-hwmon");