Re: [PATCH] hwmon: Generic ADC support for hwmon

[Guenter Roeck]

On Tue, May 15, 2012 at 10:26:48AM -0400, Jenny TC wrote:
> Currently drivers are using custom APIs to communicate with ADC driver.
> So it make sense to have generic APIs to commnicate with ADC drivers.
> This patch introduces generic APIs to communicate with ADC drivers.
> 
> Signed-off-by: Jenny TC <jenny.tc@xxxxxxxxx>

Hi Jenny,

Do you have a practical use case ?

Also, shouldn't those generic ADCs rather be supported through the IO subsystem ?
After all, hwmon is all about hardware monitoring, not to provide generic ADC access.

Thanks,
Guenter

> ---
>  drivers/hwmon/Kconfig     |    9 ++
>  drivers/hwmon/Makefile    |    1 +
>  drivers/hwmon/hwmon-adc.c |  212 +++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/hwmon-adc.h |   47 ++++++++++
>  4 files changed, 269 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/hwmon/hwmon-adc.c
>  create mode 100644 include/linux/hwmon-adc.h
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 8deedc1..203ed9d 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -37,6 +37,15 @@ config HWMON_DEBUG_CHIP
>  	  a problem with I2C support and want to see more of what is going
>  	  on.
>  
> +config HWMON_ADC
> +	bool "Hardware Monitoring Generic ADC support"
> +	default n
> +	help
> +	  Say Y here if you want the generic ADC support for Hardware Monitoring
> +	  Subsystem. Select this to enable the generic ADC driver APIs.
> +	  This enables a set of APIs to register an ADC device with hwmon
> +	  subsystem along with generic APIs to communicate with ADC driver
> +
>  comment "Native drivers"
>  
>  config SENSORS_ABITUGURU
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 6d3f11f..d91450f 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -4,6 +4,7 @@
>  
>  obj-$(CONFIG_HWMON)		+= hwmon.o
>  obj-$(CONFIG_HWMON_VID)		+= hwmon-vid.o
> +obj-$(CONFIG_HWMON_ADC)		+= hwmon-adc.o
>  
>  # APCI drivers
>  obj-$(CONFIG_SENSORS_ACPI_POWER) += acpi_power_meter.o
> diff --git a/drivers/hwmon/hwmon-adc.c b/drivers/hwmon/hwmon-adc.c
> new file mode 100644
> index 0000000..53c910e
> --- /dev/null
> +++ b/drivers/hwmon/hwmon-adc.c
> @@ -0,0 +1,212 @@
> +/*
> + *  hwmon-adc.c - Generic adc support for hardware monitoring  subsystem.
> + *
> + *  Copyright (C) 2012 Intel Corp
> + *
> + *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + *  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; version 2 of the License.
> + *
> + *  This program is distributed in the hope that it will be useful, but
> + *  WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + *  General Public License for more details.
> + *
> + *  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.,
> + *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + * Author : Jenny TC <jenny.tc@xxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-adc.h>
> +
> +LIST_HEAD(adc_lst);
> +DEFINE_MUTEX(list_lock);
> +
> +struct hwmon_adc {
> +	struct device *hwdev;
> +	struct hwmon_adc_ops *adc_ops;
> +	struct list_head list;
> +};
> +
> +/**
> + * hwmon_adc_device_register - register adc device w/ hwmon
> + * @dev: the device to register
> + *
> + * hwmon_adc_device_unregister() must be called when the device is no
> + * longer needed.
> + *
> + * Returns the pointer to the new device.
> + */
> +struct device *hwmon_adc_device_register(struct device *dev,
> +					 struct hwmon_adc_ops *adc_ops)
> +{
> +	struct hwmon_adc *adc_node;
> +	struct device *hwdev;
> +
> +	hwdev = hwmon_device_register(dev);
> +	if (IS_ERR(hwdev))
> +		return hwdev;
> +
> +	adc_node = kzalloc(sizeof(struct hwmon_adc), GFP_ATOMIC);
> +	adc_node->hwdev = hwdev;
> +	adc_node->adc_ops = adc_ops;
> +	mutex_lock(&list_lock);
> +	list_add(&adc_node->list, &adc_lst);
> +	mutex_unlock(&list_lock);
> +
> +	return hwdev;
> +}
> +EXPORT_SYMBOL(hwmon_adc_device_register);
> +
> +/**
> + * hwmon_adc_device_unregister - removes the previously registered hwmon class device
> + *
> + * @dev: the class device to destroy
> + */
> +void hwmon_adc_device_unregister(struct device *hwdev)
> +{
> +
> +	struct list_head *p, *n;
> +	struct hwmon_adc *tmp;
> +
> +	mutex_lock(&list_lock);
> +	list_for_each_safe(p, n, &adc_lst) {
> +		tmp = list_entry(p, struct hwmon_adc, list);
> +		if (tmp->hwdev == hwdev) {
> +			hwmon_device_unregister(hwdev);
> +			list_del(&tmp->list);
> +			kfree(tmp);
> +			break;
> +		}
> +	}
> +	mutex_unlock(&list_lock);
> +}
> +EXPORT_SYMBOL(hwmon_adc_device_unregister);
> +
> +static struct hwmon_adc_ops *__get_ops_byname(char *name)
> +{
> +	struct list_head *l;
> +	struct hwmon_adc *tmp;
> +	struct hwmon_adc_ops *ops = NULL;
> +
> +	mutex_lock(&list_lock);
> +	list_for_each(l, &adc_lst) {
> +		tmp = list_entry(l, struct hwmon_adc, list);
> +		if (!strcmp(dev_driver_string(tmp->hwdev->parent), name)) {
> +			ops =  tmp->adc_ops;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&list_lock);
> +	return ops;
> +}
> +
> +/**
> + * hwmon_adc_read_adc_channel - read an ADC channel
> + * @adc_name : adc device name
> + * @channel  : channel to read
> + * @adc_val  : pointer to store adc value
> + *
> + * Returns the return value from read_adc callback function on success
> + * else return -ENODEV
> + */
> +int hwmon_adc_read_channel(char *adc_name, int channel, unsigned int *adc_val)
> +{
> +	struct hwmon_adc_ops *adc_ops;
> +
> +	adc_ops = __get_ops_byname(adc_name);
> +
> +	if (adc_ops && adc_ops->read_adc)
> +		return adc_ops->read_adc(channel, adc_val);
> +
> +	return -ENODEV;
> +}
> +EXPORT_SYMBOL(hwmon_adc_read_channel);
> +
> +/**
> + * hwmon_adc_read_adc_channel - read multiple ADC channels
> + * @adc_name : adc device name
> + * @channel  : channels to read
> + * @adc_val  : pointer to store adc values
> + * @count    : number of channels to read
> + *
> + * Returns the return value from read_adc_multi callback function on success
> + * else return -ENODEV
> + */
> +int hwmon_adc_read_channel_multi(char *adc_name, int *channel,
> +		unsigned int *adc_val, int count)
> +{
> +	struct hwmon_adc_ops *adc_ops;
> +
> +	adc_ops = __get_ops_byname(adc_name);
> +
> +	if (adc_ops && adc_ops->read_adc_multi)
> +		return adc_ops->read_adc_multi(channel, adc_val, count);
> +
> +	return -ENODEV;
> +}
> +EXPORT_SYMBOL(hwmon_adc_read_channel_multi);
> +
> +/**
> + * hwmon_adc_convert_channel - convert raw ADC value
> + * to voltage/current/temperature etc.
> + *
> + * @adc_name : adc device name
> + * @channel  : channel to convert
> + * @adc_val  : adc value to convert
> + * @cvtd_val : pointer to store converted value
> + *
> + * Returns the return value from convert_adcval callback function on success
> + * else return -ENODEV
> + */
> +int hwmon_adc_convert_adcval(char *adc_name, int channel, unsigned int adc_val,
> +		      int *cvtd_val)
> +{
> +	struct hwmon_adc_ops *adc_ops;
> +
> +	adc_ops = __get_ops_byname(adc_name);
> +
> +	if (adc_ops && adc_ops->convert_adcval)
> +		return adc_ops->convert_adcval(channel, adc_val, cvtd_val);
> +
> +	return -ENODEV;
> +
> +}
> +EXPORT_SYMBOL(hwmon_adc_convert_adcval);
> +
> +/**
> + * hwmon_adc_convert_channel - convert raw ADC value
> + * to voltage/current/temperature etc.
> + *
> + * @adc_name : adc device name
> + * @channel  : channels to convert
> + * @adc_val  : adc values to convert
> + * @cvtd_val : pointer to store converted values
> + * @count    : number of channels to convert
> + *
> + * Returns the return value from convert_adcval_multi callback function on
> + * success else return -ENODEV
> + */
> +int hwmon_adc_convert_adcval_multi(char *adc_name, int *channel,
> +		unsigned int *adc_val, int *cvtd_val, int count)
> +{
> +
> +	struct hwmon_adc_ops *adc_ops;
> +
> +	adc_ops = __get_ops_byname(adc_name);
> +
> +	if (adc_ops && adc_ops->convert_adcval_multi)
> +		return adc_ops->convert_adcval_multi(channel, adc_val, cvtd_val,
> +						     count);
> +	return -ENODEV;
> +}
> +EXPORT_SYMBOL(hwmon_adc_convert_adcval_multi);
> diff --git a/include/linux/hwmon-adc.h b/include/linux/hwmon-adc.h
> new file mode 100644
> index 0000000..c4e9fc0
> --- /dev/null
> +++ b/include/linux/hwmon-adc.h
> @@ -0,0 +1,47 @@
> +/*
> + *  hwmon-adc.h - Header file for hardware monitoring generic adc support.
> + *
> + *  This file declares helper functions for generic adc support for hardware
> + *  monitoring subsystem.
> + *
> + *  Copyright (C) 2012 Intel Corp
> + *
> + *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + *  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; version 2 of the License.
> + *
> + *  This program is distributed in the hope that it will be useful, but
> + *  WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + *  General Public License for more details.
> + *
> + *  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.,
> + *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + * Author : Jenny TC <jenny.tc@xxxxxxxxx>
> + */
> +#ifndef _LINUX_HWMON_ADC_H
> +#define _LINUX_HWMON_ADC_H
> +struct hwmon_adc_ops {
> +	int (*read_adc) (int channel, unsigned int *adc_val);
> +	int (*read_adc_multi) (int *channel, unsigned int *adc_val, int count);
> +	int (*convert_adcval) (int channel, unsigned int adc_val,
> +					int *cvtd_val);
> +	int (*convert_adcval_multi) (int *channel, unsigned int *adc_val,
> +			int *cvtd_val, int count);
> +};
> +struct device *hwmon_adc_device_register(struct device *dev,
> +		struct hwmon_adc_ops *adc_ops);
> +void hwmon_adc_device_unregister(struct device *dev);
> +int hwmon_adc_read_channel(char *adc_name, int channel, unsigned int *adc_val);
> +int hwmon_adc_read_channel_multi(char *adc_name, int *channel,
> +			unsigned int *adc_val, int count);
> +int hwmon_adc_convert_adcval(char *adc_name, int channel, unsigned int adc_val,
> +			int *cvtd_val);
> +int hwmon_adc_convert_adcval_multi(char *adc_name, int *channel,
> +			unsigned int *adc_val, int *cvtd_val, int count);
> +#endif
> -- 
> 1.7.1
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/