Re: [lm-sensors] [PATCH v2 23/26] hwmon: Add JZ4740 ADC driver

[Jean Delvare <khali@linux-fr.org>]

On Sat, 19 Jun 2010 07:08:28 +0200, Lars-Peter Clausen wrote:
> This patch adds support for reading the ADCIN pin of ADC unit on JZ4740 SoCs.
> 
> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Jonathan Cameron <kernel@jic23.retrosnub.co.uk>
> Cc: lm-sensors@lm-sensors.org
> 
> ---
> Changes since v1
> - Move ADC core access synchronizing from the HWMON driver to a MFD driver. The
>   ADC driver now only reads the adcin value.
> ---
>  drivers/hwmon/Kconfig        |   11 +++
>  drivers/hwmon/Makefile       |    1 +
>  drivers/hwmon/jz4740-hwmon.c |  206 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 218 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/hwmon/jz4740-hwmon.c
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 569082c..51fc2f6 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -446,6 +446,17 @@ config SENSORS_IT87
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called it87.
>  
> +config SENSORS_JZ4740
> +	tristate "Ingenic JZ4740 SoC ADC driver"
> +	depends on MACH_JZ4740
> +    help
> +      If you say yes here you get support for the Ingenic JZ4740 SoC ADC core.
> +      It is required for the JZ4740 battery and touchscreen driver and is used
> +      to synchronize access to the adc module between those two.
> +
> +      This driver can also be build as a module. If so, the module will be
> +      called jz4740-adc.
> +
>  config SENSORS_LM63
>  	tristate "National Semiconductor LM63 and LM64"
>  	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index bca0d45..dffbdff 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -55,6 +55,7 @@ obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o
>  obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o
>  obj-$(CONFIG_SENSORS_IBMPEX)	+= ibmpex.o
>  obj-$(CONFIG_SENSORS_IT87)	+= it87.o
> +obj-$(CONFIG_SENSORS_JZ4740)	+= jz4740-hwmon.o
>  obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o
>  obj-$(CONFIG_SENSORS_K10TEMP)	+= k10temp.o
>  obj-$(CONFIG_SENSORS_LIS3LV02D) += lis3lv02d.o hp_accel.o
> diff --git a/drivers/hwmon/jz4740-hwmon.c b/drivers/hwmon/jz4740-hwmon.c
> new file mode 100644
> index 0000000..f53d15e
> --- /dev/null
> +++ b/drivers/hwmon/jz4740-hwmon.c
> @@ -0,0 +1,206 @@
> +/*
> + * 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/mfd/core.h>
> +
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +
> +struct jz4740_hwmon {
> +	struct resource *mem;
> +	void __iomem *base;
> +
> +	int irq;
> +
> +	struct mfd_cell *cell;
> +	struct device *hwmon;
> +
> +	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 jz4740_hwmon_read_adcin(struct device *dev,
> +	struct device_attribute *dev_attr, char *buf)
> +{
> +	struct jz4740_hwmon *hwmon = dev_get_drvdata(dev);
> +	unsigned long t;
> +	uint16_t val;
> +	int ret;
> +
> +	mutex_lock(&hwmon->lock);
> +
> +	INIT_COMPLETION(hwmon->read_completion);
> +
> +	enable_irq(hwmon->irq);
> +	hwmon->cell->enable(to_platform_device(dev));
> +
> +	t = wait_for_completion_interruptible_timeout(&hwmon->read_completion, HZ);
> +
> +	if (t > 0) {
> +		val = readw(hwmon->base);
> +		ret = sprintf(buf, "%d\n", val);

What is the unit of "val"? The value returned to userspace must be in
mV, so in most cases a simple conversion is needed in the driver.

> +	} else {
> +		ret = t ? t : -ETIMEDOUT;
> +	}
> +
> +	hwmon->cell->disable(to_platform_device(dev));
> +	disable_irq(hwmon->irq);
> +
> +	mutex_unlock(&hwmon->lock);
> +
> +	return ret;
> +}
> +
> +static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, jz4740_hwmon_read_adcin, NULL, 0);
> +
> +static int __devinit jz4740_hwmon_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct jz4740_hwmon *hwmon;
> +
> +	hwmon = kmalloc(sizeof(*hwmon), GFP_KERNEL);
> +
> +	hwmon->cell = pdev->dev.platform_data;
> +
> +	hwmon->irq = platform_get_irq(pdev, 0);
> +	if (hwmon->irq < 0) {
> +		ret = hwmon->irq;
> +		dev_err(&pdev->dev, "Failed to get platform irq: %d\n", ret);
> +		goto err_free;
> +	}
> +
> +	hwmon->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!hwmon->mem) {
> +		ret = -ENOENT;
> +		dev_err(&pdev->dev, "Failed to get platform mmio resource\n");
> +		goto err_free;
> +	}
> +
> +	hwmon->mem = request_mem_region(hwmon->mem->start,
> +					resource_size(hwmon->mem), pdev->name);
> +	if (!hwmon->mem) {
> +		ret = -EBUSY;
> +		dev_err(&pdev->dev, "Failed to request mmio memory region\n");
> +		goto err_free;
> +	}
> +
> +	hwmon->base = ioremap_nocache(hwmon->mem->start, resource_size(hwmon->mem));
> +	if (!hwmon->base) {
> +		ret = -EBUSY;
> +		dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
> +		goto err_release_mem_region;
> +	}
> +
> +	init_completion(&hwmon->read_completion);
> +	mutex_init(&hwmon->lock);
> +
> +	platform_set_drvdata(pdev, hwmon);
> +
> +	ret = request_irq(hwmon->irq, jz4740_hwmon_irq, 0, pdev->name, hwmon);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
> +		goto err_iounmap;
> +	}
> +	disable_irq(hwmon->irq);
> +
> +	ret = device_create_file(&pdev->dev, &sensor_dev_attr_in0_input.dev_attr);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to create sysfs file: %d\n", ret);
> +		goto err_free_irq;
> +	}

You must create a name attribute as well, if you want your device to be
supported by libsensors.

> +
> +	hwmon->hwmon = hwmon_device_register(&pdev->dev);
> +	if (IS_ERR(hwmon->hwmon)) {
> +		ret = PTR_ERR(hwmon->hwmon);
> +		goto err_remove_file;
> +	}
> +
> +	return 0;
> +
> +err_remove_file:
> +	device_remove_file(&pdev->dev, &sensor_dev_attr_in0_input.dev_attr);
> +err_free_irq:
> +	free_irq(hwmon->irq, hwmon);
> +err_iounmap:
> +	platform_set_drvdata(pdev, NULL);
> +	iounmap(hwmon->base);
> +err_release_mem_region:
> +	release_mem_region(hwmon->mem->start, resource_size(hwmon->mem));
> +err_free:
> +	kfree(hwmon);
> +
> +	return ret;
> +}
> +
> +static int __devexit jz4740_hwmon_remove(struct platform_device *pdev)
> +{
> +	struct jz4740_hwmon *hwmon = platform_get_drvdata(pdev);
> +
> +	hwmon_device_unregister(hwmon->hwmon);
> +	device_remove_file(&pdev->dev, &sensor_dev_attr_in0_input.dev_attr);
> +
> +	free_irq(hwmon->irq, hwmon);
> +
> +	iounmap(hwmon->base);
> +	release_mem_region(hwmon->mem->start, resource_size(hwmon->mem));
> +
> +	platform_set_drvdata(pdev, NULL);
> +	kfree(hwmon);
> +
> +	return 0;
> +}
> +
> +struct platform_driver jz4740_hwmon_driver = {
> +	.probe	= jz4740_hwmon_probe,
> +	.remove = __devexit_p(jz4740_hwmon_remove),
> +	.driver = {
> +		.name = "jz4740-hwmon",
> +		.owner = THIS_MODULE,
> +	},
> +};
> +
> +static int __init jz4740_hwmon_init(void)
> +{
> +	return platform_driver_register(&jz4740_hwmon_driver);
> +}
> +module_init(jz4740_hwmon_init);
> +
> +static void __exit jz4740_hwmon_exit(void)
> +{
> +	platform_driver_unregister(&jz4740_hwmon_driver);
> +}
> +module_exit(jz4740_hwmon_exit);
> +
> +MODULE_DESCRIPTION("JZ4740 SoC HWMON driver");
> +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:jz4740-hwmon");


-- 
Jean Delvare