Re: [PATCH] misc: Add driver for GP2AP002 proximity/ambient lightsensor

[Jonathan Cameron]

On 09/08/11 12:00, Donggeun Kim wrote:
> SHARP GP2AP002 is proximity and ambient light sensor.
> This patch supports it.
> 
Hi,

My main suggestion is that I can't see why threaded interrupts
won't work here and in oneshot mode they should clean your code
up a fair bit.

Otherwise, it's yet another interface for an ambient light sensor.
If you can match one of the others that would certainly be good
(though it would mean doing the conversion in kernel I think).

> Signed-off-by: Donggeun Kim <dg77.kim@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
>  Documentation/misc-devices/gp2ap002    |   47 ++++
>  drivers/misc/Kconfig                   |   10 +
>  drivers/misc/Makefile                  |    1 +
>  drivers/misc/gp2ap002.c                |  419 ++++++++++++++++++++++++++++++++
>  include/linux/platform_data/gp2ap002.h |   71 ++++++
>  5 files changed, 548 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/misc-devices/gp2ap002
>  create mode 100644 drivers/misc/gp2ap002.c
>  create mode 100644 include/linux/platform_data/gp2ap002.h
> 
> diff --git a/Documentation/misc-devices/gp2ap002 b/Documentation/misc-devices/gp2ap002
> new file mode 100644
> index 0000000..c227d19
> --- /dev/null
> +++ b/Documentation/misc-devices/gp2ap002
> @@ -0,0 +1,47 @@
> +Kernel driver gp2ap002
> +=================
> +
> +Supported chips:
> +* Sharp GP2AP002A00F proximity and ambient light sensor
> +  Datasheet: Not publicly available
> +
> +Authors: Donggeun Kim <dg77.kim@xxxxxxxxxxx>
> +	 Minkyu Kang <mk7.kang@xxxxxxxxxxx>
> +
> +Description
> +-----------
> +GP2AP002A00F is a proximity and ambient light sensor.
> +The proximity value can be obtained one of the following modes.
> +1. Normal mode: get the value of Vout gpio pin
> +	High = object is not detected
> +	Low  = object is detected
> +2. Interrupt mode: the chip generates interrupts
> +	whenever object is detected or not detected
> +	The proximity state can be obtained
> +	from VO field of PROX register
> +	1 = object is detected (value of VO field)
> +	0 = object is not detected (value of VO field)
> +
> +This chip only exports current as the result of ambient light sensor.
> +To get illuminance, CPU measures the current exported
> +from the sensor through ADC.
> +The relationship between current and illuminance is as follows:
> +	illuminance = 10^(current/10)  - (1)
> +This driver only exposes the measured current.
> +Illuminance should be calculated at the user space by (1) formula.
> +
> +Sysfs Interface
> +---------------
> +prox0_input	proximity sensor result
> +		0: object is not detected
> +		1: object is detected
> +		RO
> +
> +adc0_input	ADC result for ambient light sensor
> +		current [unit: uA]
> +		RO
My issue here is generality.  To use this value userspace needs to
have the conversion function. That means a large library of
conversion functions for every sensor out there. Does such a thing
exist?  For sensors like this we have typically done the maths
in kernel simply to avoid the issue (be it somewhat hideous!)

Also it's really not a general adc so that name is missleading.
At very least call it curr0_input to match (more or less hwmon).

> +
> +enable		enable/disable the sensor
> +		1: enable
> +		0: disable
> +		RW
We really need a better option than every sensor having it's own
varient of a manual power control..


> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 2d6423c..493373f 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -499,6 +499,16 @@ config USB_SWITCH_FSA9480
>  	  stereo and mono audio, video, microphone and UART data to use
>  	  a common connector port.
>  
> +config GP2AP002
> +	tristate "Sharp GP2AP002 proximity/ambient light sensor"
> +	depends on I2C
> +	help
> +	 Say Y here if you want to support Sharp GP2AP002
> +	 proximity/ambient light sensor.
> +
> +	 To compile this driver as a module, choose M here: the
> +	 module will be called GP2AP002.
> +
>  source "drivers/misc/c2port/Kconfig"
>  source "drivers/misc/eeprom/Kconfig"
>  source "drivers/misc/cb710/Kconfig"
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 8f3efb6..7929c26 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -47,3 +47,4 @@ obj-$(CONFIG_AB8500_PWM)	+= ab8500-pwm.o
>  obj-y				+= lis3lv02d/
>  obj-y				+= carma/
>  obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o
> +obj-$(CONFIG_GP2AP002)		+= gp2ap002.o
> diff --git a/drivers/misc/gp2ap002.c b/drivers/misc/gp2ap002.c
> new file mode 100644
> index 0000000..924f9d7
> --- /dev/null
> +++ b/drivers/misc/gp2ap002.c
> @@ -0,0 +1,419 @@
> +/*
> + *  gp2ap002.c - Sharp GP2AP002 proximity/ambient light sensor
> + *
> + *  Copyright (C) 2010 Samsung Electronics
> + *  Minkyu Kang <mk7.kang@xxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/workqueue.h>
> +#include <linux/mutex.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/gpio.h>
> +#include <linux/slab.h>
> +#include <linux/kobject.h>
> +
> +#include <linux/platform_data/gp2ap002.h>
> +
> +#define GP2AP002_PROX		0x00
> +#define GP2AP002_GAIN		0x01
> +#define GP2AP002_HYS		0x02
> +#define GP2AP002_CYCLE		0x03
> +#define GP2AP002_OPMOD		0x04
> +#define GP2AP002_CON		0x06
> +
> +#define PROX_VO_NO_DETECT	(0 << 0)
> +#define PROX_VO_DETECT		(1 << 0)
> +
> +#define GAIN_LED_SHIFT		(3)
> +#define GAIN_LED_MASK		(0x1 << GAIN_LED_SHIFT)
> +
> +#define HYS_HYSD_SHIFT		(7)
> +#define HYS_HYSD_MASK		(0x1 << HYS_HYSD_SHIFT)
> +#define HYS_HYSC_SHIFT		(5)
> +#define HYS_HYSC_MASK		(0x3 << HYS_HYSC_SHIFT)
> +#define HYS_HYSF_SHIFT		(0)
> +#define HYS_HYSF_MASK		(0xf << HYS_HYSF_SHIFT)
> +
> +#define CYCLE_CYCL_SHIFT	(3)
> +#define CYCLE_CYCL_MASK		(0x7 << CYCLE_CYCL_SHIFT)
> +#define CYCLE_OSC_SHIFT		(2)
> +#define CYCLE_OSC_MASK		(0x1 << CYCLE_OSC_SHIFT)
> +
> +#define OPMOD_ASD_SHIFT		(4)
> +#define OPMOD_ASD_MASK		(0x1 << OPMOD_ASD_SHIFT)
> +#define OPMOD_SSD_SHUTDOWN	(0)
> +#define OPMOD_SSD_OPERATING	(1)
> +#define OPMOD_VCON_SHIFT	(1)
> +#define OPMOD_VCON_MASK		(0x1 << OPMOD_VCON_SHIFT)
> +#define OPMOD_VCON_NORMAL	(0 << 1)
> +#define OPMOD_VCON_IRQ		(1 << 1)
> +
> +#define CON_OCON_SHIFT		(3)
> +#define CON_OCON_MASK		(0x3 << CON_OCON_SHIFT)
> +
> +struct gp2ap002_chip {
> +	struct i2c_client	*client;
> +	struct work_struct	work;
> +	struct mutex		lock;
> +
> +	struct gp2ap002_platform_data *pdata;
> +
> +	bool enabled;
> +
> +	/* Proximity */
> +	int mode;
> +	int proximity;
> +
> +	/* Ambient Light */
> +	int adc;
> +};
> +
> +static void gp2ap002_get_proximity(struct gp2ap002_chip *chip)
> +{
> +	struct gp2ap002_platform_data *pdata = chip->pdata;
> +	int prox_mode;
> +
> +	prox_mode = pdata->prox_mode << OPMOD_VCON_SHIFT;
> +	/* interrupt output mode */
> +	if ((prox_mode & OPMOD_VCON_MASK) == OPMOD_VCON_IRQ) {
> +		/* Determine whether the object is detected
> +		   by reading proximity output register */
> +		chip->proximity = i2c_smbus_read_byte_data(chip->client,
> +					GP2AP002_PROX) & PROX_VO_DETECT;
> +	} else { /* normal output mode */
> +		/* vo_gpio is changed from high to low
> +		   when the object is detected */
> +		chip->proximity = !gpio_get_value(pdata->vout_gpio);
> +	}
Silly question but is the value really not available in that register
if we aren't in interrupt mode?  Seems 'odd', but then it's hardware so
what the heck.  If it is I'd just always read that register so as to
have cleaner code (at the cost of a small bus transaction).
> +}
> +
> +static int gp2ap002_chip_enable(struct gp2ap002_chip *chip, bool enable)
> +{
> +	struct gp2ap002_platform_data *pdata = chip->pdata;
> +	int ret;
> +	u8 value;
> +
> +	if (enable == chip->enabled)
> +		return 0;
> +
> +	value = (pdata->analog_sleep << OPMOD_ASD_SHIFT) |
> +		(pdata->prox_mode << OPMOD_VCON_SHIFT);
> +	/* software shutdown mode */
> +	if (enable)
> +		value |= OPMOD_SSD_OPERATING;
> +	else /* operating mode */
> +		value |= OPMOD_SSD_SHUTDOWN;
> +
> +	ret = i2c_smbus_write_byte_data(chip->client, GP2AP002_OPMOD, value);
> +	if (ret < 0)
> +		goto out;
> +
> +	chip->enabled = enable;
> +out:
> +	return ret;
> +}
> +
> +static void gp2ap002_work(struct work_struct *work)
> +{
> +	struct gp2ap002_chip *chip = container_of(work,
> +			struct gp2ap002_chip, work);
> +
> +	mutex_lock(&chip->lock);
> +	gp2ap002_get_proximity(chip);
> +
> +	kobject_uevent(&chip->client->dev.kobj, KOBJ_CHANGE);
as you can poll on sysfs files, would it not be cleaner to use
that interface to tell userspace there are new values?
> +	mutex_unlock(&chip->lock);
> +
> +	enable_irq(chip->client->irq);
> +}
> +
> +static irqreturn_t gp2ap002_irq(int irq, void *data)
> +{
> +	struct gp2ap002_chip *chip = data;
> +
> +	disable_irq_nosync(irq);
> +	schedule_work(&chip->work);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static ssize_t gp2ap002_show_proximity(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct gp2ap002_chip *chip = dev_get_drvdata(dev);
> +
> +	mutex_lock(&chip->lock);
> +	gp2ap002_get_proximity(chip);
> +	mutex_unlock(&chip->lock);
> +
> +	if (chip->proximity < 0)
> +		return chip->proximity;
> +	return sprintf(buf, "%d\n", chip->proximity);
> +}
> +static DEVICE_ATTR(prox0_input, S_IRUGO, gp2ap002_show_proximity, NULL);
> +
> +static ssize_t gp2ap002_show_light_adc(struct device *dev,
> +			struct device_attribute *attr, char *buf)
> +{
> +	struct gp2ap002_chip *chip = dev_get_drvdata(dev);
> +	struct gp2ap002_platform_data *pdata = chip->pdata;
> +
> +	if (pdata->get_adc) {
> +		mutex_lock(&chip->lock);
> +		chip->adc = pdata->get_adc();
> +		mutex_unlock(&chip->lock);
> +	}
> +	if (chip->adc < 0)
> +		return chip->adc;
> +	return sprintf(buf, "%d\n", chip->adc);
> +}
> +static DEVICE_ATTR(adc0_input, S_IRUGO, gp2ap002_show_light_adc, NULL);
> +
> +static ssize_t gp2ap002_store_enable(struct device *dev,
> +	struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct gp2ap002_chip *chip = dev_get_drvdata(dev);
> +	unsigned long value;
> +	int ret;
> +
> +	if (strict_strtoul(buf, 0, &value))
> +		return -EINVAL;
> +
> +	ret = gp2ap002_chip_enable(chip, !!value);
> +	if (ret < 0)
> +		return ret;
> +
> +	return count;
> +}
> +static ssize_t gp2ap002_show_enable(struct device *dev,
> +		struct device_attribute *attr, char *buf)
> +{
> +	struct gp2ap002_chip *chip = dev_get_drvdata(dev);
> +	return sprintf(buf, "%d\n", chip->enabled);
> +}
> +static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
> +		gp2ap002_show_enable, gp2ap002_store_enable);
> +
> +static struct attribute *gp2ap002_attributes[] = {
> +	&dev_attr_prox0_input.attr,
> +	&dev_attr_adc0_input.attr,
> +	&dev_attr_enable.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group gp2ap002_attribute_group = {
> +	.attrs = gp2ap002_attributes,
> +};
> +
> +static int gp2ap002_initialize(struct gp2ap002_chip *chip)
> +{
> +	struct gp2ap002_platform_data *pdata = chip->pdata;
> +	int ret;
> +	u8 value;
> +
> +	/* GAIN register */
> +	value = (pdata->led_mode << GAIN_LED_SHIFT) & GAIN_LED_MASK;
> +	ret = i2c_smbus_write_byte_data(chip->client, GP2AP002_GAIN, value);
> +	if (ret < 0)
> +		goto out;
> +
> +	/* HYS register */
> +	value = (pdata->hysd << HYS_HYSD_SHIFT) & HYS_HYSD_MASK;
> +	value |= (pdata->hysc << HYS_HYSC_SHIFT) & HYS_HYSC_MASK;
> +	value |= (pdata->hysf << HYS_HYSF_SHIFT) & HYS_HYSF_MASK;
> +	ret = i2c_smbus_write_byte_data(chip->client, GP2AP002_HYS, value);
> +	if (ret < 0)
> +		goto out;
> +
> +	/* CYCLE register */
> +	value = (pdata->cycle << CYCLE_CYCL_SHIFT) & CYCLE_CYCL_MASK;
> +	value |= (pdata->oscillator << CYCLE_OSC_SHIFT) & CYCLE_OSC_MASK;
> +	ret = i2c_smbus_write_byte_data(chip->client, GP2AP002_CYCLE, value);
> +	if (ret < 0)
> +		goto out;
> +
> +	/* CON register */
> +	value = (pdata->vout_control << CON_OCON_SHIFT) & CON_OCON_MASK;
> +	ret = i2c_smbus_write_byte_data(chip->client, GP2AP002_CYCLE, value);
> +out:
> +	return ret;
> +}
> +
> +static int __devinit gp2ap002_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct gp2ap002_chip *chip;
> +	struct gp2ap002_platform_data *pdata;
> +	int ret;
> +
> +	pdata = client->dev.platform_data;
> +	if (!pdata) {
> +		dev_err(&client->dev, "No platform init data supplied\n");
> +		return -ENODEV;
> +	}
> +
> +	chip = kzalloc(sizeof(struct gp2ap002_chip), GFP_KERNEL);
> +	if (!chip) {
> +		dev_err(&client->dev, "Failed to allocate driver structure\n");
> +		return -ENOMEM;
> +	}
> +
> +	if (client->irq > 0) {
> +		unsigned long irq_flag = IRQF_DISABLED;
> +
Could do with some explanation. I have no idea what VCON is!
> +		if (chip->mode == OPMOD_VCON_IRQ)
> +			irq_flag |= IRQF_TRIGGER_FALLING;
> +		else
> +			irq_flag |= IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
> +
  WHy not threaded?
> +		ret = request_irq(client->irq, gp2ap002_irq, irq_flag,
> +				"GP2AP002 sensor", chip);
> +		if (ret) {
> +			dev_err(&client->dev, "Failed to request irq: %d\n",
> +				client->irq);
> +			goto error_irq;
> +		}
> +	}
> +
> +	chip->client = client;
> +	i2c_set_clientdata(client, chip);
> +	INIT_WORK(&chip->work, gp2ap002_work);
> +	mutex_init(&chip->lock);
> +	chip->pdata = pdata;
> +
> +	ret = sysfs_create_group(&client->dev.kobj, &gp2ap002_attribute_group);
> +	if (ret) {
> +		dev_err(&client->dev,
> +			"Failed to create attribute group\n");
> +		goto error_sysfs_group;
> +	}
> +
> +	if (pdata->power_enable)
> +		pdata->power_enable(true);
> +
> +	ret = gp2ap002_initialize(chip);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to initialize chip\n");
> +		goto error_chip_initialize;
> +	}
> +
> +	ret = gp2ap002_chip_enable(chip, pdata->chip_enable);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to enable chip\n");
> +		goto error_chip_enable;
> +	}
> +
> +	dev_info(&client->dev, "%s registered\n", id->name);
> +	return 0;
> +
> +error_chip_enable:
> +error_chip_initialize:
> +	sysfs_remove_group(&client->dev.kobj, &gp2ap002_attribute_group);
> +error_sysfs_group:
> +	if (client->irq > 0)
> +		free_irq(client->irq, chip);
> +error_irq:
> +	kfree(chip);
> +	return ret;
> +}
> +
> +static int __devexit gp2ap002_remove(struct i2c_client *client)
> +{
> +	struct gp2ap002_chip *chip = i2c_get_clientdata(client);
> +
> +	disable_irq_nosync(client->irq);
> +	cancel_work_sync(&chip->work);
> +
> +	if (client->irq > 0)
> +		free_irq(client->irq, chip);
> +
> +	sysfs_remove_group(&client->dev.kobj, &gp2ap002_attribute_group);
> +
> +	gp2ap002_chip_enable(chip, false);
> +
> +	if (chip->pdata->power_enable)
> +		chip->pdata->power_enable(false);
> +
> +	kfree(chip);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int gp2ap002_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct gp2ap002_chip *chip = i2c_get_clientdata(client);
> +
> +	cancel_work_sync(&chip->work);
> +	gp2ap002_chip_enable(chip, false);
> +
> +	if (chip->pdata->power_enable)
> +		chip->pdata->power_enable(false);
> +
> +	return 0;
> +}
> +
> +static int gp2ap002_resume(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct gp2ap002_chip *chip = i2c_get_clientdata(client);
> +
> +	if (chip->pdata->power_enable)
> +		chip->pdata->power_enable(true);
> +
> +	gp2ap002_chip_enable(chip, true);
> +
> +	return 0;
> +}
> +#else
> +#define gp2ap002_suspend NULL
> +#define gp2ap002_resume NULL
> +#endif
> +
> +static const struct i2c_device_id gp2ap002_id[] = {
> +	{ "GP2AP002", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, gp2ap002_id);
> +
> +static const struct dev_pm_ops gp2ap002_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(gp2ap002_suspend, gp2ap002_resume)
> +};
> +
> +static struct i2c_driver gp2ap002_i2c_driver = {
> +	.driver = {
> +		.name	= "GP2AP002",
> +		.owner	= THIS_MODULE,
> +		.pm	= &gp2ap002_pm_ops,
> +	},
> +	.probe		= gp2ap002_probe,
> +	.remove		= __devexit_p(gp2ap002_remove),
> +	.id_table	= gp2ap002_id,
> +};
> +
> +static int __init gp2ap002_init(void)
> +{
> +	return i2c_add_driver(&gp2ap002_i2c_driver);
> +}
> +module_init(gp2ap002_init);
> +
> +static void __exit gp2ap002_exit(void)
> +{
> +	i2c_del_driver(&gp2ap002_i2c_driver);
> +}
> +module_exit(gp2ap002_exit);
> +
> +MODULE_AUTHOR("Minkyu Kang <mk7.kang@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("GP2AP002 Proximity/Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/platform_data/gp2ap002.h b/include/linux/platform_data/gp2ap002.h
> new file mode 100644
> index 0000000..134e7ef
> --- /dev/null
> +++ b/include/linux/platform_data/gp2ap002.h
> @@ -0,0 +1,71 @@
> +/*
> + *  Copyright (C) 2010 Samsung Electronics
> + *  Minkyu Kang <mk7.kang@xxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __GP2AP002_H_
> +#define __GP2AP002_H_
> +
> +/**
> + * struct gp2ap002_platform_data
> + * @get_adc: call back function to get adc value for ambient light sensor
> + * @power_enable: call back function to control voltage supply for chip
> + * @vout_gpio: gpio number for Vout pin
> + * @led_mode: select switch for LED's resistance
> + *	0: 2x higher setting,
> + *	1: normal setting
> + * @hysd, hysc, hysf: a set of these bits adjusts the sensitivity,
> + *	determining characteristics of the detection distance and
> + *	its hysteresis
> + *	0 <= hysd <= 1
> + *	0 <= hysc <= 3
> + *	0 <= hysf <= 15
> + * @cycle: determine the detection cycle
> + *	0: 8ms (response time)
> + *	1: 16ms (response time)
> + *	2: 32ms (response time)
> + *	3: 64ms (response time)
> + *	4: 128ms (response time)
> + *	5: 256ms (response time)
> + *	6: 512ms (response time)
> + *	7: 1024ms (response time)
> + * @oscillator: select switch for internal clock frequency hopping
> + *	0: effective,
> + *	1: ineffective
> + * @analog_sleep: select switch for analog sleep function
> + *	0: ineffective
> + *	1: effective
> + * @prox_mode: determine output method control for Vout pin
> + *	0: normal mode
> + *	1: interrupt_mode
> + * @vout_control: select switch for enabling/disabling Vout pin
> + *	0: enable
> + *	2: force to go Low
> + *	3: force to go High
> + * @chip_enable: determine enabling/disabling software shutdown function
> + *	0: shutdown mode
> + *	1: operating mode
> + */
> +struct gp2ap002_platform_data {
> +	int (*get_adc)(void);
> +	void (*power_enable)(bool);
> +	int vout_gpio;
> +
None of these needs to be int as far as I can see so 
you might as well make them u8s/u16s or bitfields of
the right size.
> +	int led_mode;
> +	int hysd;
> +	int hysc;
> +	int hysf;
> +	int cycle;
> +	int oscillator;
> +	int analog_sleep;
> +	int prox_mode;
> +	int vout_control;
> +
> +	bool chip_enable;
> +};
> +
> +#endif

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