Message-ID: <4CA21885.1040603@cam.ac.uk>
Date:	Tue, 28 Sep 2010 17:32:05 +0100
From:	Jonathan Cameron <jic23@....ac.uk>
To:	Alan Cox <alan@...ux.intel.com>
CC:	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Add ALS drivers for the apds9802als

On 09/28/10 15:18, Alan Cox wrote:
> From: anantha <anantha.narayanan@...el.com>
> 
> This adds support for the ADPS9802ALS sensor.
Hi Alan,

One last point, hwmon equivalent syntax for the naming would be
lux0_input rather than the lux_input0 you have here.

I'm still not keen on the lack of association between sensing range
and what it is of, but then we don't have a unified naming convention
for this as yet.
> 
> Cleanup by Alan Cox
> 	- move mutexes to cover more things
> 	- report I/O errors back to user space
> 	- report range and values in LUX
> 
> Signed-off-by: Anantha Narayanan <anantha.narayanan@...el.com>
> [The 4K and 64K in the hw spec acutally means 4095 (12bit) and 65535 (16bit).]
> Signed-off-by: Hong Liu <hong.liu@...el.com>
> Signed-off-by: Alan Cox <alan@...ux.intel.com>
> ---
> 
>  drivers/misc/Kconfig       |   10 +
>  drivers/misc/Makefile      |    1 
>  drivers/misc/apds9802als.c |  308 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 319 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/misc/apds9802als.c
> 
> 
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 53b21ff..d6ec9ce 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -293,6 +293,16 @@ config SGI_GRU_DEBUG
>  	This option enables addition debugging code for the SGI GRU driver. If
>  	you are unsure, say N.
>  
> +config APDS9802ALS
> +	tristate "Medfield Avago APDS9802 ALS Sensor module"
> +	depends on I2C
> +	help
> +	  If you say yes here you get support for the ALS APDS9802 ambient
> +	  light sensor.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called apds9802als.
> +
>  config ISL29003
>  	tristate "Intersil ISL29003 ambient light sensor"
>  	depends on I2C && SYSFS
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 4c771a2..0e5f2a5 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_SGI_XP)		+= sgi-xp/
>  obj-$(CONFIG_SGI_GRU)		+= sgi-gru/
>  obj-$(CONFIG_CS5535_MFGPT)	+= cs5535-mfgpt.o
>  obj-$(CONFIG_HP_ILO)		+= hpilo.o
> +obj-$(CONFIG_APDS9802ALS)	+= apds9802als.o
>  obj-$(CONFIG_ISL29003)		+= isl29003.o
>  obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
>  obj-$(CONFIG_EP93XX_PWM)	+= ep93xx_pwm.o
> diff --git a/drivers/misc/apds9802als.c b/drivers/misc/apds9802als.c
> new file mode 100644
> index 0000000..a52270d
> --- /dev/null
> +++ b/drivers/misc/apds9802als.c
> @@ -0,0 +1,308 @@
> +/*
> + * apds9802als.c - apds9802  ALS Driver
> + *
> + * Copyright (C) 2009 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.
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/delay.h>
> +#include <linux/mutex.h>
> +#include <linux/sysfs.h>
> +#include <linux/hwmon-sysfs.h>
> +
> +#define ALS_MIN_RANGE_VAL 1
> +#define ALS_MAX_RANGE_VAL 2
> +#define POWER_STA_ENABLE 1
> +#define POWER_STA_DISABLE 0
> +#define APDS9802ALS_I2C_ADDR 0x29
> +
> +#define DRIVER_NAME "apds9802als"
> +
> +struct als_data {
> +	struct device *hwmon_dev;
> +	bool needresume;
> +	struct mutex mutex;
> +};
> +
> +static ssize_t als_sensing_range_show(struct device *dev,
> +			struct device_attribute *attr,  char *buf)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	int  val;
> +
> +	val = i2c_smbus_read_byte_data(client, 0x81);
> +	if (val < 0)
> +		return val;
> +	if (val & 1)
> +		return sprintf(buf, "4095\n");
> +	else
> +		return sprintf(buf, "65535\n");
> +}
> +
> +static ssize_t als_lux_input0_data_show(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct als_data *data = i2c_get_clientdata(client);
> +	unsigned int ret_val;
> +	int temp;
> +
> +	/* Protect against parallel reads */
> +	mutex_lock(&data->mutex);
> +	temp = i2c_smbus_read_byte_data(client, 0x8C);/*LSB data*/
> +	if (temp < 0) {
> +		ret_val = temp;
> +		goto failed;
> +	}
> +	ret_val = i2c_smbus_read_byte_data(client, 0x8D);/*MSB data*/
> +	if (ret_val < 0)
> +		goto failed;
> +	mutex_unlock(&data->mutex);
> +	ret_val = (ret_val << 8) | temp;
> +	return sprintf(buf, "%d\n", ret_val);
> +failed:
> +	mutex_unlock(&data->mutex);
> +	return ret_val;
> +}
> +
> +static ssize_t als_sensing_range_store(struct device *dev,
> +		struct device_attribute *attr, const  char *buf, size_t count)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct als_data *data = i2c_get_clientdata(client);
> +	unsigned int ret_val;
> +	unsigned long val;
> +
> +	if (strict_strtoul(buf, 10, &val))
> +		return -EINVAL;
> +
> +	if (val < 4096)
> +		val = 1;
> +	else if (val < 65536)
> +		val = 2;
> +	else
> +		return -ERANGE;
> +
> +	/* Make sure nobody else reads/modifies/writes 0x81 while we
> +	   are active */
> +
> +	mutex_lock(&data->mutex);
> +
> +	ret_val = i2c_smbus_read_byte_data(client, 0x81);
> +	if (ret_val < 0)
> +		goto fail;
> +
> +	/* Reset the bits before setting them */
> +	ret_val = ret_val & 0xFA;
> +
> +	if (val == 1) /* Setting the continous measurement up to 4k LUX */
> +		ret_val = (ret_val | 0x05);
> +	else /* Setting the continous measurement up to 64k LUX*/
> +		ret_val = (ret_val | 0x04);
> +
> +	ret_val = i2c_smbus_write_byte_data(client, 0x81, ret_val);
> +	if (ret_val >= 0) {
> +		/* All OK */
> +		mutex_unlock(&data->mutex);
> +		return count;
> +	}
> +fail:
> +	mutex_unlock(&data->mutex);
> +	return ret_val;
> +}
> +
> +static ssize_t als_power_status_show(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	int ret_val;
> +	ret_val = i2c_smbus_read_byte_data(client, 0x80);
> +	if (ret_val < 0)
> +		return ret_val;
> +	ret_val = ret_val & 0x01;
> +	return sprintf(buf, "%d\n", ret_val);
> +}
> +
> +static int als_set_power_state(struct i2c_client *client, bool on_off)
> +{
> +	int ret_val;
> +	struct als_data *data = i2c_get_clientdata(client);
> +
> +	mutex_lock(&data->mutex);
> +	ret_val = i2c_smbus_read_byte_data(client, 0x80);
> +	if (ret_val < 0)
> +		goto fail;
> +	if (on_off)
> +		ret_val = ret_val | 0x01;
> +	else
> +		ret_val = ret_val & 0xFE;
> +	ret_val = i2c_smbus_write_byte_data(client, 0x80, ret_val);
> +fail:
> +	mutex_unlock(&data->mutex);
> +	return ret_val;
> +}
> +
> +static ssize_t als_power_status_store(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct als_data *data = i2c_get_clientdata(client);
> +	unsigned long val;
> +	int ret_val;
> +
> +	if (strict_strtoul(buf, 10, &val))
> +		return -EINVAL;
> +	if (val == POWER_STA_ENABLE) {
> +		ret_val = als_set_power_state(client, true);
> +		data->needresume = true;
> +	} else if (val == POWER_STA_DISABLE) {
> +		ret_val = als_set_power_state(client, false);
> +		data->needresume = false;
> +	} else
> +		return -EINVAL;
> +	if (ret_val < 0)
> +		return ret_val;
> +	return count;
> +}
> +
> +static DEVICE_ATTR(sensing_range, S_IRUGO | S_IWUSR,
> +	als_sensing_range_show, als_sensing_range_store);
> +static DEVICE_ATTR(lux_input0, S_IRUGO, als_lux_input0_data_show, NULL);
> +static DEVICE_ATTR(power_state, S_IRUGO | S_IWUSR,
> +	als_power_status_show, als_power_status_store);
> +
> +static struct attribute *mid_att_als[] = {
> +	&dev_attr_sensing_range.attr,
> +	&dev_attr_lux_input0.attr,
> +	&dev_attr_power_state.attr,
> +	NULL
> +};
> +
> +static struct attribute_group m_als_gr = {
> +	.name = "apds9802als",
> +	.attrs = mid_att_als
> +};
> +
> +static int als_set_default_config(struct i2c_client *client)
> +{
> +	int ret_val;
> +	/* Write the command and then switch on */
> +	ret_val = i2c_smbus_write_byte_data(client, 0x80, 0x01);
> +	if (ret_val < 0) {
> +		dev_err(&client->dev, "failed default switch on write\n");
> +		return ret_val;
> +	}
> +	/* Continous from 1Lux to 64k Lux */
> +	ret_val = i2c_smbus_write_byte_data(client, 0x81, 0x04);
> +	if (ret_val < 0)
> +		dev_err(&client->dev, "failed default LUX on write\n");
> +	return ret_val;
> +}
> +
> +static int  apds9802als_probe(struct i2c_client *client,
> +					const struct i2c_device_id *id)
> +{
> +	int res;
> +	struct als_data *data;
> +
> +	data = kzalloc(sizeof(struct als_data), GFP_KERNEL);
> +	if (data == NULL) {
> +		dev_err(&client->dev, "Memory allocation failed");
> +		return -ENOMEM;
> +	}
> +	i2c_set_clientdata(client, data);
> +	res = sysfs_create_group(&client->dev.kobj, &m_als_gr);
> +	if (res) {
> +		dev_err(&client->dev, "device create file failed\n");
> +		goto als_error1;
> +	}
> +	dev_info(&client->dev,
> +		"%s apds9802als: ALS chip found\n", client->name);
> +	als_set_default_config(client);
> +	data->needresume = true;
> +	mutex_init(&data->mutex);
> +	return res;
> +als_error1:
> +	i2c_set_clientdata(client, NULL);
> +	kfree(data);
> +	return res;
> +}
> +
> +static int apds9802als_remove(struct i2c_client *client)
> +{
> +	struct als_data *data = i2c_get_clientdata(client);
> +	sysfs_remove_group(&client->dev.kobj, &m_als_gr);
> +	kfree(data);
> +	return 0;
> +}
> +
> +static int apds9802als_suspend(struct i2c_client *client, pm_message_t mesg)
> +{
> +	als_set_power_state(client, false);
> +	return 0;
> +}
> +
> +static int apds9802als_resume(struct i2c_client *client)
> +{
> +	struct als_data *data = i2c_get_clientdata(client);
> +
> +	if (data->needresume == true)
> +		als_set_power_state(client, true);
> +	return 0;
> +}
> +
> +static struct i2c_device_id apds9802als_id[] = {
> +	{ DRIVER_NAME, 0 },
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, apds9802als_id);
> +
> +static struct i2c_driver apds9802als_driver = {
> +	.driver = {
> +	.name = DRIVER_NAME,
> +	.owner = THIS_MODULE,
> +	},
> +	.probe = apds9802als_probe,
> +	.remove = apds9802als_remove,
> +	.suspend = apds9802als_suspend,
> +	.resume = apds9802als_resume,
> +	.id_table = apds9802als_id,
> +};
> +
> +static int __init sensor_apds9802als_init(void)
> +{
> +	return i2c_add_driver(&apds9802als_driver);
> +}
> +
> +static void  __exit sensor_apds9802als_exit(void)
> +{
> +	i2c_del_driver(&apds9802als_driver);
> +}
> +module_init(sensor_apds9802als_init);
> +module_exit(sensor_apds9802als_exit);
> +
> +MODULE_AUTHOR("Anantha Narayanan <Anantha.Narayanan@...el.com");
> +MODULE_DESCRIPTION("Avago apds9802als ALS Driver");
> +MODULE_LICENSE("GPL v2");
> 
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