lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 1 Sep 2014 19:39:53 +0200 (CEST)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	Daniel Baluta <daniel.baluta@...el.com>
cc:	jic23@...nel.org, daniel.baluta@...il.com, knaack.h@....de,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Tsechih_Lin@...s.com
Subject: Re: [PATCH v4] iio: Add Dyna-Image AL3320A ambient light sensor
 driver

Hello Daniel,

> Minimal implementation. This driver provides raw illuminance readings.
> 
> This is based on drivers/hwmon/al3320.c (*) driver from msm tree written
> by Tsechih Lin <Tsechih_Lin@...s.com>
> 
> * https://android.googlesource.com/kernel/msm.git
> 
> Signed-off-by: Daniel Baluta <daniel.baluta@...el.com>
> ---
> Changes since v3: (reported by Hartmut and Jonathan)
> 	* dropped the local store for the range, instead read it when necessary
> 	* removed wrapper functions
> 	* added in_illuminance_scale_available attribute
> 	* fix bug when reading raw value, use i2c_smbus_read_word instead of
> 	  i2c_smbus_read_word_swapped and fix the endianess after read.

no need to fix endianness

> 	* small coding style fixes
> 
> Changes since v2: (reported by Peter Meerwald)
>         * removed definition of DATA_HIGH and SW_RESET as they are not used
>         * added a comment to al3320a_get_adc_value() function
>         * added thresholds on TODO list
>         * small style fixes
> 
> Changes since v1: (reported by Peter Meerwald)
>         * used u8 instead of int for passing gain and mean_time
>         * used i2c_smbus_read_word_swapped instead of 2 x i2c_smbus_read_byte_data
>         * used devm_iio_device_register instead of iio_device_register
>         * small style fixes
> 
> 
>  drivers/iio/light/Kconfig   |  10 ++
>  drivers/iio/light/Makefile  |   1 +
>  drivers/iio/light/al3320a.c | 229 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 240 insertions(+)
>  create mode 100644 drivers/iio/light/al3320a.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index bf05ca5..5bea821 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -17,6 +17,16 @@ config ADJD_S311
>  	 This driver can also be built as a module.  If so, the module
>  	 will be called adjd_s311.
>  
> +config AL3320A
> +	tristate "AL3320A ambient light sensor"
> +	depends on I2C
> +	help
> +	 Say Y here if you want to build a driver for the Dyna Image AL3320A
> +	 ambient light sensor.
> +
> +	 To compile this driver as a module, choose M here: the
> +	 module will be called al3320a.
> +
>  config APDS9300
>  	tristate "APDS9300 ambient light sensor"
>  	depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index 8b8c09f..47877a3 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -4,6 +4,7 @@
>  
>  # When adding new entries keep the list in alphabetical order
>  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
> +obj-$(CONFIG_AL3320A)		+= al3320a.o
>  obj-$(CONFIG_APDS9300)		+= apds9300.o
>  obj-$(CONFIG_CM32181)		+= cm32181.o
>  obj-$(CONFIG_CM36651)		+= cm36651.o
> diff --git a/drivers/iio/light/al3320a.c b/drivers/iio/light/al3320a.c
> new file mode 100644
> index 0000000..ad9135a
> --- /dev/null
> +++ b/drivers/iio/light/al3320a.c
> @@ -0,0 +1,229 @@
> +/*
> + * AL3320A - Dyna Image Ambient Light Sensor
> + *
> + * Copyright (c) 2014, Intel Corporation.
> + *
> + * This file is subject to the terms and conditions of version 2 of
> + * the GNU General Public License.  See the file COPYING in the main
> + * directory of this archive for more details.
> + *
> + * IIO driver for AL3320A (7-bit I2C slave address 0x1C).
> + *
> + * TODO: interrupt support, thresholds
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define AL3320A_DRV_NAME "al3320a"
> +
> +#define AL3320A_REG_CONFIG		0x00
> +#define AL3320A_REG_STATUS		0x01
> +#define AL3320A_REG_INT			0x02
> +#define AL3320A_REG_WAIT		0x06
> +#define AL3320A_REG_CONFIG_RANGE	0x07
> +#define AL3320A_REG_PERSIST		0x08
> +#define AL3320A_REG_MEAN_TIME		0x09
> +#define AL3320A_REG_ADUMMY		0x0A
> +#define AL3320A_REG_DATA_LOW		0x22
> +
> +#define AL3320A_REG_LOW_THRESH_LOW	0x30
> +#define AL3320A_REG_LOW_THRESH_HIGH	0x31
> +#define AL3320A_REG_HIGH_THRESH_LOW	0x32
> +#define AL3320A_REG_HIGH_THRESH_HIGH	0x33
> +
> +#define AL3320A_CONFIG_DISABLE		0x00
> +#define AL3320A_CONFIG_ENABLE		0x01
> +
> +#define AL3320A_GAIN_SHIFT		1
> +
> +/* chip params default values */
> +#define AL3320A_DEFAULT_MEAN_TIME	4
> +#define AL3320A_DEFAULT_WAIT_TIME	0 /* no waiting */
> +
> +#define AL3320A_SCALE_AVAILABLE "0.512 0.128 0.032 0.01"
> +
> +enum al3320a_range {
> +	AL3320A_RANGE_1, /* 33.28K lux */
> +	AL3320A_RANGE_2, /* 8.32K lux  */
> +	AL3320A_RANGE_3, /* 2.08K lux  */
> +	AL3320A_RANGE_4  /* 0.65K lux  */
> +};
> +
> +static const int al3320a_scales[][2] = {
> +	{0, 512000}, {0, 128000}, {0, 32000}, {0, 10000}
> +};
> +
> +struct al3320a_data {
> +	struct i2c_client *client;
> +};
> +
> +static const struct iio_chan_spec al3320a_channels[] = {
> +	{
> +		.type	= IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +	}
> +};
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available, AL3320A_SCALE_AVAILABLE);
> +
> +static struct attribute *al3320a_attributes[] = {
> +	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group al3320a_attribute_group = {
> +	.attrs = al3320a_attributes,
> +};
> +
> +static int al3320a_init(struct al3320a_data *data)
> +{
> +	int ret;
> +
> +	/* power on */
> +	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG,
> +					AL3320A_CONFIG_ENABLE);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_CONFIG_RANGE,
> +					AL3320A_RANGE_3 << AL3320A_GAIN_SHIFT);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_MEAN_TIME,
> +					AL3320A_DEFAULT_MEAN_TIME);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, AL3320A_REG_WAIT,
> +					AL3320A_DEFAULT_WAIT_TIME);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int al3320a_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int *val,
> +			    int *val2, long mask)
> +{
> +	struct al3320a_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		/*
> +		 * ALS ADC value is stored in two adjacent registers:
> +		 * - low byte of output is stored at AL3320A_REG_DATA_LOW
> +		 * - high byte of output is stored at AL3320A_REG_DATA_LOW + 1
> +		 */
> +		ret = i2c_smbus_read_word_data(data->client,
> +					       AL3320A_REG_DATA_LOW);

i2c_smbus_read_word_data() must be used if the data is in I2C byte order 
(i.e. LSB first)

i2c_smbus_read_word_swapped() must be used if the data is NOT in I2C byte 
order (i.e. MSB first)

this has nothing to do with CPU byteorder; i2c_smbus_read_word_xxx() will 
take care to report the 16-bit value in native endianness

> +		if (ret < 0)
> +			return ret;
> +		*val = le16_to_cpu((__le16)ret);

so it should be
*val = ret;

> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		ret = i2c_smbus_read_byte_data(data->client,
> +					       AL3320A_REG_CONFIG_RANGE);
> +		if (ret < 0)
> +			return ret;
> +		ret >>= AL3320A_GAIN_SHIFT;
> +		*val = al3320a_scales[ret][0];
> +		*val2 = al3320a_scales[ret][1];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	}
> +	return -EINVAL;
> +}
> +
> +static int al3320a_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan, int val,
> +			     int val2, long mask)
> +{
> +	struct al3320a_data *data = iio_priv(indio_dev);
> +	int i;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		for (i = 0; i < ARRAY_SIZE(al3320a_scales); i++) {
> +			if (val == al3320a_scales[i][0] &&
> +			    val2 == al3320a_scales[i][1])
> +				return i2c_smbus_write_byte_data(data->client,
> +					AL3320A_REG_CONFIG_RANGE,
> +					i << AL3320A_GAIN_SHIFT);
> +		}
> +		break;
> +	}
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info al3320a_info = {
> +	.driver_module	= THIS_MODULE,
> +	.read_raw	= al3320a_read_raw,
> +	.write_raw	= al3320a_write_raw,
> +	.attrs		= &al3320a_attribute_group,
> +};
> +
> +static int al3320a_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct al3320a_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	data->client = client;
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &al3320a_info;
> +	indio_dev->name = AL3320A_DRV_NAME;
> +	indio_dev->channels = al3320a_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(al3320a_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = al3320a_init(data);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "al3320a chip init failed\n");
> +		return ret;
> +	}
> +	return devm_iio_device_register(&client->dev, indio_dev);
> +}
> +
> +static int al3320a_remove(struct i2c_client *client)
> +{
> +	return i2c_smbus_write_byte_data(client, AL3320A_REG_CONFIG,
> +					 AL3320A_CONFIG_DISABLE);
> +}
> +
> +static const struct i2c_device_id al3320a_id[] = {
> +	{"al3320a", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, al3320a_id);
> +
> +static struct i2c_driver al3320a_driver = {
> +	.driver = {
> +		.name = AL3320A_DRV_NAME,
> +	},
> +	.probe		= al3320a_probe,
> +	.remove		= al3320a_remove,
> +	.id_table	= al3320a_id,
> +};
> +
> +module_i2c_driver(al3320a_driver);
> +
> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@...el.com>");
> +MODULE_DESCRIPTION("AL3320A Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists