diff options
Diffstat (limited to 'drivers/hwmon/jz4740-hwmon.c')
| -rw-r--r-- | drivers/hwmon/jz4740-hwmon.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/hwmon/jz4740-hwmon.c b/drivers/hwmon/jz4740-hwmon.c new file mode 100644 index 000000000..2d40a2e77 --- /dev/null +++ b/drivers/hwmon/jz4740-hwmon.c @@ -0,0 +1,146 @@ +/* + * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de> + * JZ4740 SoC HWMON driver + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 675 Mass Ave, Cambridge, MA 02139, USA. + * + */ + +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/io.h> + +#include <linux/completion.h> +#include <linux/mfd/core.h> + +#include <linux/hwmon.h> + +struct jz4740_hwmon { + void __iomem *base; + int irq; + const struct mfd_cell *cell; + struct platform_device *pdev; + struct completion read_completion; + struct mutex lock; +}; + +static irqreturn_t jz4740_hwmon_irq(int irq, void *data) +{ + struct jz4740_hwmon *hwmon = data; + + complete(&hwmon->read_completion); + return IRQ_HANDLED; +} + +static ssize_t in0_input_show(struct device *dev, + struct device_attribute *dev_attr, char *buf) +{ + struct jz4740_hwmon *hwmon = dev_get_drvdata(dev); + struct platform_device *pdev = hwmon->pdev; + struct completion *completion = &hwmon->read_completion; + long t; + unsigned long val; + int ret; + + mutex_lock(&hwmon->lock); + + reinit_completion(completion); + + enable_irq(hwmon->irq); + hwmon->cell->enable(pdev); + + t = wait_for_completion_interruptible_timeout(completion, HZ); + + if (t > 0) { + val = readw(hwmon->base) & 0xfff; + val = (val * 3300) >> 12; + ret = sprintf(buf, "%lu\n", val); + } else { + ret = t ? t : -ETIMEDOUT; + } + + hwmon->cell->disable(pdev); + disable_irq(hwmon->irq); + + mutex_unlock(&hwmon->lock); + + return ret; +} + +static DEVICE_ATTR_RO(in0_input); + +static struct attribute *jz4740_attrs[] = { + &dev_attr_in0_input.attr, + NULL +}; + +ATTRIBUTE_GROUPS(jz4740); + +static int jz4740_hwmon_probe(struct platform_device *pdev) +{ + int ret; + struct device *dev = &pdev->dev; + struct jz4740_hwmon *hwmon; + struct device *hwmon_dev; + struct resource *mem; + + hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL); + if (!hwmon) + return -ENOMEM; + + hwmon->cell = mfd_get_cell(pdev); + + hwmon->irq = platform_get_irq(pdev, 0); + if (hwmon->irq < 0) { + dev_err(&pdev->dev, "Failed to get platform irq: %d\n", + hwmon->irq); + return hwmon->irq; + } + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + hwmon->base = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(hwmon->base)) + return PTR_ERR(hwmon->base); + + hwmon->pdev = pdev; + init_completion(&hwmon->read_completion); + mutex_init(&hwmon->lock); + + ret = devm_request_irq(dev, hwmon->irq, jz4740_hwmon_irq, 0, + pdev->name, hwmon); + if (ret) { + dev_err(&pdev->dev, "Failed to request irq: %d\n", ret); + return ret; + } + disable_irq(hwmon->irq); + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, "jz4740", hwmon, + jz4740_groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static struct platform_driver jz4740_hwmon_driver = { + .probe = jz4740_hwmon_probe, + .driver = { + .name = "jz4740-hwmon", + }, +}; + +module_platform_driver(jz4740_hwmon_driver); + +MODULE_DESCRIPTION("JZ4740 SoC HWMON driver"); +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:jz4740-hwmon"); |