Date:	Wed, 30 Jul 2008 12:44:07 +0200
From:	"Hans J. Koch" <hjk@...utronix.de>
To:	Marc Pignat <marc.pignat@...s.ch>
Cc:	lm-sensors@...sensors.org, linux-kernel@...r.kernel.org,
	David Brownell <david-b@...bell.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Mark M. Hoffman" <mhoffman@...htlink.com>,
	Tobias Himmer <tobias@...mer-online.de>
Subject: Re: [RFC,PATCH v2] hwmon: ADC124S501 generic driver

Am Wed, 30 Jul 2008 12:16:00 +0200
schrieb Marc Pignat <marc.pignat@...s.ch>:

> SPI driver for analog to digital converters national semiconductor
> ADC081S101, ADC124S501, ...
> 
> Code for 8 channels by : Tobias Himmer <tobias@...mer-online.de>
> 
> Signed-off-by: Marc Pignat <marc.pignat@...s.ch>
> ---
> 
> Hi all!
> 
> patch against 2.6.27-rc1, tested on a custom arm board and only
> compile-tested on x86.
> 
> This driver add support for National Semiconductor ADC<bb><c>S<sss>
> chip family, where:
>  * bb  is the resolution in number of bits (8, 10, 12)
>  * c   is the number of channels (1, 2, 4, 8)
>  * sss is the maximum conversion speed (021 for 200 kSPS, 051 for 500
>    kSPS and 101 for 1 MSPS)
> 
> Changes from v1:
>  * error recovery fixed
>  * support for 8 channels, thanks to Tobias

Hm, but you didn't merge Tobias' patch. Was that intentional?
Do you plan to integrate his patch, or do we have two separate patches?

Thanks,
Hans

>  * better CodingStyle
> 
> Thanks for your comments and testing ;)
> 
> Best regards
> 
> Marc
> 
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 00ff533..9c4a579 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -390,6 +390,22 @@ config SENSORS_LM70
>  	  This driver can also be built as a module.  If so, the
> module will be called lm70.
>  
> +config SENSORS_ADCXX
> +	tristate "National Semiconductor ADCxxxSxxx"
> +	depends on SPI_MASTER && EXPERIMENTAL
> +	help
> +	  If you say yes here you get support for the National
> Semiconductor
> +	  ADC<bb><c>S<sss> chip family, where
> +	  * bb  is the resolution in number of bits (8, 10, 12)
> +	  * c   is the number of channels (1, 2, 4)
> +	  * sss is the maximum conversion speed (021 for 200 kSPS,
> 051 for 500
> +	    kSPS and 101 for 1 MSPS)
> +
> +	  Examples : ADC081S101, ADC124S501, ...
> +
> +	  This driver can also be built as a module.  If so, the
> module
> +	  will be called adcxx.
> +
>  config SENSORS_LM75
>  	tristate "National Semiconductor LM75 and compatibles"
>  	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index d098677..026ba1e 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_SENSORS_W83791D)	+= w83791d.o
>  obj-$(CONFIG_SENSORS_ABITUGURU)	+= abituguru.o
>  obj-$(CONFIG_SENSORS_ABITUGURU3)+= abituguru3.o
>  obj-$(CONFIG_SENSORS_AD7418)	+= ad7418.o
> +obj-$(CONFIG_SENSORS_ADCXX)	+= adcxx.o
>  obj-$(CONFIG_SENSORS_ADM1021)	+= adm1021.o
>  obj-$(CONFIG_SENSORS_ADM1025)	+= adm1025.o
>  obj-$(CONFIG_SENSORS_ADM1026)	+= adm1026.o
> diff --git a/drivers/hwmon/adcxx.c b/drivers/hwmon/adcxx.c
> new file mode 100644
> index 0000000..d920fe5
> --- /dev/null
> +++ b/drivers/hwmon/adcxx.c
> @@ -0,0 +1,292 @@
> +/*
> + * adcxx.c
> + *
> + * The adcxx4s is an AD converter family from National Semiconductor
> (NS).
> + *
> + * Copyright (c) 2008 Marc Pignat <marc.pignat@...s.ch>
> + *
> + * The adcxx4s communicates with a host processor via an
> SPI/Microwire Bus
> + * interface. This driver supports the whole family of devices with
> name
> + * ADC<bb><c>S<sss>, where
> + * * bb is the resolution in number of bits (8, 10, 12)
> + * * c is the number of channels (1, 2, 4)
> + * * sss is the maximum conversion speed (021 for 200 kSPS, 051 for
> 500 kSPS
> + *   and 101 for 1 MSPS)
> + *
> + * Complete datasheets are available at National's website here:
> + * http://www.national.com/ds/DC/ADC<bb><c>S<sss>.pdf
> + *
> + * Handling of 8, 10 and 12 bits converters are the same, the
> + * unavailable bits are 0 :)
> + *
> + * 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.
> + *
> + * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/sysfs.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/mutex.h>
> +#include <linux/spi/spi.h>
> +
> +#define DRVNAME		"adcxx"
> +
> +struct adcxx {
> +	struct device *hwmon_dev;
> +	struct mutex lock;
> +	u32 channels;
> +	u32 reference; /* in millivolts */
> +};
> +
> +/* sysfs hook function */
> +static ssize_t adcxx_read(struct device *dev,
> +		struct device_attribute *devattr, char *buf)
> +{
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct sensor_device_attribute *attr =
> to_sensor_dev_attr(devattr);
> +	struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +
> +	u8 tx_buf[2] = { attr->index << 3 }; /* other bits are don't
> care */
> +	u8 rx_buf[2];
> +	int status;
> +	int value;
> +
> +	if (mutex_lock_interruptible(&adc->lock))
> +		return -ERESTARTSYS;
> +
> +	status = spi_write_then_read(spi, tx_buf, sizeof(tx_buf),
> +					rx_buf, sizeof(rx_buf));
> +	if (status < 0) {
> +		dev_warn(dev, "spi_write_then_read failed with
> status %d\n",
> +				status);
> +		goto out;
> +	}
> +
> +	value = (rx_buf[0] << 8) + rx_buf[1];
> +	dev_dbg(dev, "raw value = 0x%x\n", value);
> +
> +	value = value * adc->reference >> 12;
> +	status = sprintf(buf, "%d\n", value);
> +out:
> +	mutex_unlock(&adc->lock);
> +	return status;
> +}
> +
> +static ssize_t adcxx_show_min(struct device *dev,
> +		struct device_attribute *devattr, char *buf)
> +{
> +	/* The minimum reference is 0 for this chip family */
> +	return sprintf(buf, "0\n");
> +}
> +
> +static ssize_t adcxx_show_max(struct device *dev,
> +		struct device_attribute *devattr, char *buf)
> +{
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +
> +	u32 reference;
> +
> +	if (mutex_lock_interruptible(&adc->lock))
> +		return -ERESTARTSYS;
> +
> +	reference = adc->reference;
> +
> +	mutex_unlock(&adc->lock);
> +
> +	return sprintf(buf, "%d\n", reference);
> +}
> +
> +static ssize_t adcxx_set_max(struct device *dev,
> +	struct device_attribute *devattr, const char *buf, size_t
> count) +{
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +
> +	unsigned long value;
> +
> +	if (strict_strtoul(buf, 10, &value))
> +		return -EINVAL;
> +
> +	if (mutex_lock_interruptible(&adc->lock))
> +		return -ERESTARTSYS;
> +
> +	adc->reference = value;
> +
> +	mutex_unlock(&adc->lock);
> +
> +	return count;
> +}
> +
> +static ssize_t adcxx_show_name(struct device *dev, struct
> device_attribute
> +			      *devattr, char *buf)
> +{
> +	struct spi_device *spi = to_spi_device(dev);
> +	struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +
> +	return sprintf(buf, "adcxx%ds\n", adc->channels);
> +}
> +
> +static struct sensor_device_attribute ad_input[] = {
> +	SENSOR_ATTR(name, S_IRUGO, adcxx_show_name, NULL, 0),
> +
> +	/* The reference is the same for all channels */
> +	SENSOR_ATTR(in_min, S_IRUGO, adcxx_show_min, NULL, 0),
> +	SENSOR_ATTR(in_max, S_IWUSR | S_IRUGO, adcxx_show_max,
> +					adcxx_set_max, 0),
> +
> +	SENSOR_ATTR(in0_input, S_IRUGO, adcxx_read, NULL, 0),
> +	SENSOR_ATTR(in1_input, S_IRUGO, adcxx_read, NULL, 1),
> +	SENSOR_ATTR(in2_input, S_IRUGO, adcxx_read, NULL, 2),
> +	SENSOR_ATTR(in3_input, S_IRUGO, adcxx_read, NULL, 3),
> +};
> +
> +/*----------------------------------------------------------------------*/
> +
> +static int __devinit adcxx_probe(struct spi_device *spi, int
> channels) +{
> +	struct adcxx *adc;
> +	int status;
> +	int i;
> +
> +	adc = kzalloc(sizeof *adc, GFP_KERNEL);
> +	if (!adc)
> +		return -ENOMEM;
> +
> +	/* set a default value for the reference */
> +	adc->reference = 3300;
> +
> +	adc->channels = channels;
> +
> +	mutex_init(&adc->lock);
> +
> +	dev_set_drvdata(&spi->dev, adc);
> +
> +	for (i = 0; i < 3 + adc->channels; i++) {
> +		status = device_create_file(&spi->dev,
> &ad_input[i].dev_attr);
> +		if (status)
> +			goto out_dev_create_file_failed;
> +	}
> +
> +	adc->hwmon_dev = hwmon_device_register(&spi->dev);
> +	if (IS_ERR(adc->hwmon_dev)) {
> +		dev_dbg(&spi->dev, "hwmon_device_register
> failed.\n");
> +		status = PTR_ERR(adc->hwmon_dev);
> +		goto out_dev_reg_failed;
> +	}
> +
> +	return 0;
> +
> +out_dev_create_file_failed:
> +	hwmon_device_unregister(adc->hwmon_dev);
> +	for (i = 0; i < 3 + adc->channels; i++)
> +		device_remove_file(&spi->dev, &ad_input[i].dev_attr);
> +out_dev_reg_failed:
> +	dev_set_drvdata(&spi->dev, NULL);
> +	kfree(adc);
> +	return status;
> +}
> +
> +static int __devinit adcxx1s_probe(struct spi_device *spi)
> +{
> +	return adcxx_probe(spi, 1);
> +}
> +
> +static int __devinit adcxx2s_probe(struct spi_device *spi)
> +{
> +	return adcxx_probe(spi, 2);
> +}
> +
> +static int __devinit adcxx4s_probe(struct spi_device *spi)
> +{
> +	return adcxx_probe(spi, 4);
> +}
> +
> +static int __devexit adcxx_remove(struct spi_device *spi)
> +{
> +	struct adcxx *adc = dev_get_drvdata(&spi->dev);
> +	int i;
> +
> +	hwmon_device_unregister(adc->hwmon_dev);
> +	for (i = 0; i < 3 + adc->channels; i++)
> +		device_remove_file(&spi->dev, &ad_input[i].dev_attr);
> +	dev_set_drvdata(&spi->dev, NULL);
> +	kfree(adc);
> +
> +	return 0;
> +}
> +
> +static struct spi_driver adcxx1s_driver = {
> +	.driver = {
> +		.name	= "adcxx1s",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= adcxx1s_probe,
> +	.remove	= __devexit_p(adcxx_remove),
> +};
> +
> +static struct spi_driver adcxx2s_driver = {
> +	.driver = {
> +		.name	= "adcxx2s",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= adcxx2s_probe,
> +	.remove	= __devexit_p(adcxx_remove),
> +};
> +
> +static struct spi_driver adcxx4s_driver = {
> +	.driver = {
> +		.name	= "adcxx4s",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= adcxx4s_probe,
> +	.remove	= __devexit_p(adcxx_remove),
> +};
> +
> +static int __init init_adcxx(void)
> +{
> +	int status;
> +	status = spi_register_driver(&adcxx1s_driver);
> +	if (status)
> +		return status;
> +
> +	status = spi_register_driver(&adcxx2s_driver);
> +	if (status)
> +		return status;
> +
> +	return spi_register_driver(&adcxx4s_driver);
> +}
> +
> +static void __exit exit_adcxx(void)
> +{
> +	spi_unregister_driver(&adcxx1s_driver);
> +	spi_unregister_driver(&adcxx2s_driver);
> +	spi_unregister_driver(&adcxx4s_driver);
> +}
> +
> +module_init(init_adcxx);
> +module_exit(exit_adcxx);
> +
> +MODULE_AUTHOR("Marc Pignat");
> +MODULE_DESCRIPTION("National Semiconductor adcxx4sxxx Linux driver");
> +MODULE_LICENSE("GPL");
> +
> +MODULE_ALIAS("adcxx1s");
> +MODULE_ALIAS("adcxx2s");
> +MODULE_ALIAS("adcxx4s");
> --
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