[PATCH 1/3] ACPI: introduce ACPI ALS driver

[PATCH 1/3] ACPI: introduce ACPI ALS driver

[Zhang Rui]

introduce ACPI ALS device driver.

ACPI spec defines ACPI Ambient Light Sensor device (hid ACPI0008),
which provides a standard interface by which the OS may query properties
of the ambient light environment the system is currently operating in,
as well as the ability to detect meaningful changes in these values when the
environment changes.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 Documentation/acpi/debug.txt |    1 
 drivers/acpi/Kconfig         |    9 
 drivers/acpi/Makefile        |    1 
 drivers/acpi/als.c           |  407 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/debug.c         |    1 
 include/acpi/acpi_drivers.h  |    1 
 6 files changed, 420 insertions(+)

Index: linux-2.6/drivers/acpi/als.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/acpi/als.c
@@ -0,0 +1,407 @@
+/*
+ *  als.c - ACPI Ambient Light Sensor Driver
+ *
+ *  Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  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.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+
+#define ACPI_ALS_CLASS			"als"
+#define ACPI_ALS_DEVICE_NAME		"Ambient Light Sensor"
+#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
+#define ACPI_ALS_NOTIFY_COLOR_TEMP	0x81
+#define ACPI_ALS_NOTIFY_RESPONSE	0x82
+
+#define _COMPONENT		ACPI_ALS_COMPONENT
+ACPI_MODULE_NAME("als");
+
+MODULE_AUTHOR("Zhang Rui");
+MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");
+
+static int acpi_als_add(struct acpi_device *device);
+static int acpi_als_remove(struct acpi_device *device, int type);
+static int acpi_als_resume(struct acpi_device *device);
+static void acpi_als_notify(struct acpi_device *device, u32 event);
+
+static const struct acpi_device_id als_device_ids[] = {
+	{"ACPI0008", 0},
+	{"", 0},
+};
+
+MODULE_DEVICE_TABLE(acpi, als_device_ids);
+
+static struct acpi_driver acpi_als_driver = {
+	.name = "als",
+	.class = ACPI_ALS_CLASS,
+	.ids = als_device_ids,
+	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
+	.ops = {
+		.add = acpi_als_add,
+		.resume = acpi_als_resume,
+		.remove = acpi_als_remove,
+		.notify = acpi_als_notify,
+		},
+};
+
+struct als_cap {
+	u8 _ALI:1;
+	u8 _ALC:1;
+	u8 _ALT:1;
+	u8 _ALR:1;
+	u8 _ALP:1;
+};
+
+struct als_mapping {
+	int adjustment;
+	int illuminance;
+};
+
+struct acpi_als {
+	struct acpi_device *device;
+	struct als_cap cap;
+	int illuminance;
+	int chromaticity;
+	int temperature;
+	int polling;
+	int count;
+	struct als_mapping *mappings;
+};
+
+#define ALS_INVALID_VALUE_LOW		0
+#define ALS_INVALID_VALUE_HIGH		-1
+
+/* --------------------------------------------------------------------------
+		Ambient Light Sensor device Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * acpi_als_get_illuminance - get the current ambient light illuminance
+ */
+static int acpi_als_get_illuminance(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long illuminance;
+
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALI", NULL,
+				  &illuminance);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status,
+				"Error reading ALS illuminance"));
+		als->illuminance = ALS_INVALID_VALUE_LOW;
+		return -ENODEV;
+	}
+	als->illuminance = illuminance;
+	return 0;
+}
+
+/*
+ * acpi_als_get_color_chromaticity - get the ambient light color chromaticity
+ */
+static int acpi_als_get_color_chromaticity(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long chromaticity;
+
+	if (!als->cap._ALC)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALC", NULL,
+				  &chromaticity);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALC not available\n"));
+		als->cap._ALC = 0;
+		return -ENODEV;
+	}
+	als->chromaticity = chromaticity;
+	return 0;
+}
+
+/*
+ * acpi_als_get_color_temperature - get the ambient light color temperature
+ */
+static int acpi_als_get_color_temperature(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long temperature;
+
+	if (!als->cap._ALT)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALT", NULL,
+				  &temperature);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALT not available\n"));
+		als->cap._ALT = 0;
+		return -ENODEV;
+	}
+	als->temperature = temperature;
+	return 0;
+}
+
+/*
+ * acpi_als_get_mappings - get the ALS illuminance mappings
+ *
+ * Return a package of ALS illuminance to display adjustment mappings
+ * that can be used by OS to calibrate its ambient light policy
+ * for a given sensor configuration.
+ */
+static int acpi_als_get_mappings(struct acpi_als *als)
+{
+	int result = 0;
+	acpi_status status = AE_OK;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *alr = NULL;
+	int i, j;
+
+	status =
+	    acpi_evaluate_object(als->device->handle, "_ALR", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS mappings"));
+		return -ENODEV;
+	}
+
+	alr = buffer.pointer;
+	if (!alr || (alr->type != ACPI_TYPE_PACKAGE)) {
+		printk(KERN_ERR PREFIX "Invalid _ALR data\n");
+		result = -EFAULT;
+		goto end;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d illuminance mappings\n",
+			  alr->package.count));
+
+	als->count = alr->package.count;
+	als->mappings =
+	    kmalloc(sizeof(struct als_mapping) * als->count, GFP_KERNEL);
+	if (!als->mappings) {
+		result = -ENOMEM;
+		goto end;
+	}
+
+	for (i = 0, j = 0; i < als->count; i++) {
+		struct als_mapping *mapping = &(als->mappings[j]);
+		union acpi_object *element = &(alr->package.elements[i]);
+
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count != 2)
+			continue;
+
+		if (element->package.elements[0].type != ACPI_TYPE_INTEGER ||
+		    element->package.elements[1].type != ACPI_TYPE_INTEGER)
+			continue;
+
+		mapping->adjustment =
+		    element->package.elements[0].integer.value;
+		mapping->illuminance =
+		    element->package.elements[1].integer.value;
+		j++;
+
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Mapping [%d]: "
+				  "adjuestment [%d] illuminance[%d]\n",
+				  i, mapping->adjustment,
+				  mapping->illuminance));
+	}
+
+end:
+	kfree(buffer.pointer);
+	return result;
+}
+
+/*
+ * acpi_als_get_polling - get the current ambient light illuminance
+ */
+static int acpi_als_get_polling(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long polling;
+
+	if (!als->cap._ALP)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALP", NULL, &polling);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALP not available\n"));
+		als->cap._ALP = 0;
+		return -ENODEV;
+	}
+	als->polling = polling;
+	return 0;
+}
+
+static int acpi_als_find_cap(struct acpi_als *als)
+{
+	acpi_handle dummy;
+
+	memset(&als->cap, 0, sizeof(als->cap));
+
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALI", &dummy)))
+		als->cap._ALI = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALC", &dummy)))
+		als->cap._ALC = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALT", &dummy)))
+		als->cap._ALT = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALR", &dummy)))
+		als->cap._ALR = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALP", &dummy)))
+		als->cap._ALP = 1;
+
+	if (!als->cap._ALI || !als->cap._ALR) {
+		ACPI_EXCEPTION((AE_INFO, AE_NOT_FOUND,
+				"Mandatory methods _ALI/_ALR not available"));
+		return -ENODEV;
+	}
+	return 0;
+}
+
+/* --------------------------------------------------------------------------
+				 Driver Model
+   -------------------------------------------------------------------------- */
+
+static void acpi_als_notify(struct acpi_device *device, u32 event)
+{
+	struct acpi_als *als = acpi_driver_data(device);
+
+	if (!als)
+		return;
+
+	switch (event) {
+	case ACPI_ALS_NOTIFY_ILLUMINANCE:
+		acpi_als_get_illuminance(als);
+		break;
+	case ACPI_ALS_NOTIFY_COLOR_TEMP:
+		acpi_als_get_color_temperature(als);
+		acpi_als_get_color_chromaticity(als);
+		break;
+	case ACPI_ALS_NOTIFY_RESPONSE:
+		acpi_als_get_mappings(als);
+		break;
+	default:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Unsupported event [0x%x]\n", event));
+	}
+	acpi_bus_generate_proc_event(device, event, (u32) als->illuminance);
+	acpi_bus_generate_netlink_event(device->pnp.device_class,
+					dev_name(&device->dev), event,
+					(u32) als->illuminance);
+	return;
+}
+
+static int acpi_als_add(struct acpi_device *device)
+{
+	int result = 0;
+	struct acpi_als *als = NULL;
+
+	if (!device)
+		return -EINVAL;
+
+	als = kzalloc(sizeof(struct acpi_als), GFP_KERNEL);
+	if (!als)
+		return -ENOMEM;
+
+	als->device = device;
+	strcpy(acpi_device_name(device), ACPI_ALS_DEVICE_NAME);
+	strcpy(acpi_device_class(device), ACPI_ALS_CLASS);
+	device->driver_data = als;
+
+	result = acpi_als_find_cap(als);
+	if (result)
+		goto end;
+
+	result = acpi_als_get_illuminance(als);
+	if (result)
+		goto end;
+
+	result = acpi_als_get_mappings(als);
+	if (result)
+		goto end;
+
+	acpi_als_get_color_temperature(als);
+	acpi_als_get_color_chromaticity(als);
+	acpi_als_get_polling(als);
+
+end:
+	if (result)
+		kfree(als);
+	return result;
+}
+
+static int acpi_als_resume(struct acpi_device *device)
+{
+	struct acpi_als *als;
+
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+
+	als = acpi_driver_data(device);
+
+	if (acpi_als_get_illuminance(als))
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Failed to re-evaluate"
+				  " ALS illuminance during resume\n"));
+	return 0;
+}
+
+static int acpi_als_remove(struct acpi_device *device, int type)
+{
+	struct acpi_als *als;
+
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+
+	als = acpi_driver_data(device);
+	if (!als)
+		return -EINVAL;
+
+	if (als->mappings)
+		kfree(als->mappings);
+	kfree(als);
+	return 0;
+}
+
+static int __init acpi_als_init(void)
+{
+	int result;
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	result = acpi_bus_register_driver(&acpi_als_driver);
+	if (result < 0)
+		return -ENODEV;
+	return 0;
+}
+
+static void __exit acpi_als_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_als_driver);
+	return;
+}
+
+module_init(acpi_als_init);
+module_exit(acpi_als_exit);
Index: linux-2.6/drivers/acpi/Kconfig
===================================================================
--- linux-2.6.orig/drivers/acpi/Kconfig
+++ linux-2.6/drivers/acpi/Kconfig
@@ -333,4 +333,13 @@ config ACPI_SBS
 	  To compile this driver as a module, choose M here:
 	  the modules will be called sbs and sbshc.
 
+config ACPI_ALS
+	tristate "Ambient Light Sensor driver"
+	depends on X86
+	help
+	  This driver supports the ACPI Ambient Light Sensor.
+
+	  To compile this driver as a module, choose M here:
+	  the modules will be called als.
+
 endif	# ACPI
Index: linux-2.6/drivers/acpi/Makefile
===================================================================
--- linux-2.6.orig/drivers/acpi/Makefile
+++ linux-2.6/drivers/acpi/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_ACPI_HOTPLUG_MEMORY) += acp
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
 obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
 obj-$(CONFIG_ACPI_SBS)		+= sbs.o
+obj-$(CONFIG_ACPI_ALS)		+= als.o
 
 # processor has its own "processor." module_param namespace
 processor-y			:= processor_core.o processor_throttling.o
Index: linux-2.6/Documentation/acpi/debug.txt
===================================================================
--- linux-2.6.orig/Documentation/acpi/debug.txt
+++ linux-2.6/Documentation/acpi/debug.txt
@@ -63,6 +63,7 @@ shows the supported mask values, current
     ACPI_MEMORY_DEVICE_COMPONENT    0x08000000
     ACPI_VIDEO_COMPONENT            0x10000000
     ACPI_PROCESSOR_COMPONENT        0x20000000
+    ACPI_ALS_COMPONENT              0x40000000
 
 debug_level
 -----------
Index: linux-2.6/drivers/acpi/debug.c
===================================================================
--- linux-2.6.orig/drivers/acpi/debug.c
+++ linux-2.6/drivers/acpi/debug.c
@@ -53,6 +53,7 @@ static const struct acpi_dlayer acpi_deb
 	ACPI_DEBUG_INIT(ACPI_MEMORY_DEVICE_COMPONENT),
 	ACPI_DEBUG_INIT(ACPI_VIDEO_COMPONENT),
 	ACPI_DEBUG_INIT(ACPI_PROCESSOR_COMPONENT),
+	ACPI_DEBUG_INIT(ACPI_ALS_COMPONENT),
 };
 
 static const struct acpi_dlevel acpi_debug_levels[] = {
Index: linux-2.6/include/acpi/acpi_drivers.h
===================================================================
--- linux-2.6.orig/include/acpi/acpi_drivers.h
+++ linux-2.6/include/acpi/acpi_drivers.h
@@ -49,6 +49,7 @@
 #define ACPI_MEMORY_DEVICE_COMPONENT	0x08000000
 #define ACPI_VIDEO_COMPONENT		0x10000000
 #define ACPI_PROCESSOR_COMPONENT	0x20000000
+#define ACPI_ALS_COMPONENT		0x40000000
 
 /*
  * _HID definitions

Re: [PATCH 1/3] ACPI: introduce ACPI ALS driver

[Zhang Rui]

On Mon, 2009-08-03 at 17:11 +0800, Zhang, Rui wrote:
> introduce ACPI ALS device driver.
> 
> ACPI spec defines ACPI Ambient Light Sensor device (hid ACPI0008),
> which provides a standard interface by which the OS may query properties
> of the ambient light environment the system is currently operating in,
> as well as the ability to detect meaningful changes in these values when the
> environment changes.
> 
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Refreshed patch that fixes a memory leak.

introduce ACPI ALS device driver.

ACPI spec defines ACPI Ambient Light Sensor device (hid ACPI0008),
which provides a standard interface by which the OS may query properties
of the ambient light environment the system is currently operating in,
as well as the ability to detect meaningful changes in these values when the
environment changes.

This patch introduces the ACPI ALS driver.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 Documentation/acpi/debug.txt |    1 
 drivers/acpi/Kconfig         |    9 
 drivers/acpi/Makefile        |    1 
 drivers/acpi/als.c           |  417 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/debug.c         |    1 
 include/acpi/acpi_drivers.h  |    1 
 6 files changed, 430 insertions(+)

Index: linux-2.6/drivers/acpi/als.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/acpi/als.c
@@ -0,0 +1,417 @@
+/*
+ *  als.c - ACPI Ambient Light Sensor Driver
+ *
+ *  Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *  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.,
+ *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <acpi/acpi_bus.h>
+#include <acpi/acpi_drivers.h>
+
+#define ACPI_ALS_CLASS			"als"
+#define ACPI_ALS_DEVICE_NAME		"Ambient Light Sensor"
+#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
+#define ACPI_ALS_NOTIFY_COLOR_TEMP	0x81
+#define ACPI_ALS_NOTIFY_RESPONSE	0x82
+
+#define _COMPONENT		ACPI_ALS_COMPONENT
+ACPI_MODULE_NAME("als");
+
+MODULE_AUTHOR("Zhang Rui");
+MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
+MODULE_LICENSE("GPL");
+
+static int acpi_als_add(struct acpi_device *device);
+static int acpi_als_remove(struct acpi_device *device, int type);
+static int acpi_als_resume(struct acpi_device *device);
+static void acpi_als_notify(struct acpi_device *device, u32 event);
+
+static const struct acpi_device_id als_device_ids[] = {
+	{"ACPI0008", 0},
+	{"", 0},
+};
+
+MODULE_DEVICE_TABLE(acpi, als_device_ids);
+
+static struct acpi_driver acpi_als_driver = {
+	.name = "als",
+	.class = ACPI_ALS_CLASS,
+	.ids = als_device_ids,
+	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
+	.ops = {
+		.add = acpi_als_add,
+		.resume = acpi_als_resume,
+		.remove = acpi_als_remove,
+		.notify = acpi_als_notify,
+		},
+};
+
+struct als_cap {
+	u8 _ALI:1;
+	u8 _ALC:1;
+	u8 _ALT:1;
+	u8 _ALR:1;
+	u8 _ALP:1;
+};
+
+struct als_mapping {
+	int adjustment;
+	int illuminance;
+};
+
+struct acpi_als {
+	struct acpi_device *device;
+	struct als_cap cap;
+	int illuminance;
+	int chromaticity;
+	int temperature;
+	int polling;
+	int count;
+	struct als_mapping *mappings;
+};
+
+#define ALS_INVALID_VALUE_LOW		0
+#define ALS_INVALID_VALUE_HIGH		-1
+
+/* --------------------------------------------------------------------------
+		Ambient Light Sensor device Management
+   -------------------------------------------------------------------------- */
+
+/*
+ * acpi_als_get_illuminance - get the current ambient light illuminance
+ */
+static int acpi_als_get_illuminance(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long illuminance;
+
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALI", NULL,
+				  &illuminance);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status,
+				"Error reading ALS illuminance"));
+		als->illuminance = ALS_INVALID_VALUE_LOW;
+		return -ENODEV;
+	}
+	als->illuminance = illuminance;
+	return 0;
+}
+
+/*
+ * acpi_als_get_color_chromaticity - get the ambient light color chromaticity
+ */
+static int acpi_als_get_color_chromaticity(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long chromaticity;
+
+	if (!als->cap._ALC)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALC", NULL,
+				  &chromaticity);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALC not available\n"));
+		als->cap._ALC = 0;
+		return -ENODEV;
+	}
+	als->chromaticity = chromaticity;
+	return 0;
+}
+
+/*
+ * acpi_als_get_color_temperature - get the ambient light color temperature
+ */
+static int acpi_als_get_color_temperature(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long temperature;
+
+	if (!als->cap._ALT)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALT", NULL,
+				  &temperature);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALT not available\n"));
+		als->cap._ALT = 0;
+		return -ENODEV;
+	}
+	als->temperature = temperature;
+	return 0;
+}
+
+/*
+ * acpi_als_get_mappings - get the ALS illuminance mappings
+ *
+ * Return a package of ALS illuminance to display adjustment mappings
+ * that can be used by OS to calibrate its ambient light policy
+ * for a given sensor configuration.
+ */
+static int acpi_als_get_mappings(struct acpi_als *als)
+{
+	int result = 0;
+	acpi_status status = AE_OK;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *alr = NULL;
+	int i, j;
+
+	/* Free the old mappings */
+	if (als->mappings) {
+		kfree(als->mappings);
+		als->mappings = NULL;
+	}
+
+	status =
+	    acpi_evaluate_object(als->device->handle, "_ALR", NULL, &buffer);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS mappings"));
+		return -ENODEV;
+	}
+
+	alr = buffer.pointer;
+	if (!alr || (alr->type != ACPI_TYPE_PACKAGE)) {
+		printk(KERN_ERR PREFIX "Invalid _ALR data\n");
+		result = -EFAULT;
+		goto end;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d illuminance mappings\n",
+			  alr->package.count));
+
+	als->count = alr->package.count;
+
+	if (!als->count)
+		return 0;
+
+	als->mappings =
+	    kmalloc(sizeof(struct als_mapping) * als->count, GFP_KERNEL);
+	if (!als->mappings) {
+		result = -ENOMEM;
+		goto end;
+	}
+
+	for (i = 0, j = 0; i < als->count; i++) {
+		struct als_mapping *mapping = &(als->mappings[j]);
+		union acpi_object *element = &(alr->package.elements[i]);
+
+		if (element->type != ACPI_TYPE_PACKAGE)
+			continue;
+
+		if (element->package.count != 2)
+			continue;
+
+		if (element->package.elements[0].type != ACPI_TYPE_INTEGER ||
+		    element->package.elements[1].type != ACPI_TYPE_INTEGER)
+			continue;
+
+		mapping->adjustment =
+		    element->package.elements[0].integer.value;
+		mapping->illuminance =
+		    element->package.elements[1].integer.value;
+		j++;
+
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Mapping [%d]: "
+				  "adjuestment [%d] illuminance[%d]\n",
+				  i, mapping->adjustment,
+				  mapping->illuminance));
+	}
+
+end:
+	kfree(buffer.pointer);
+	return result;
+}
+
+/*
+ * acpi_als_get_polling - get the current ambient light illuminance
+ */
+static int acpi_als_get_polling(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long polling;
+
+	if (!als->cap._ALP)
+		return -ENODEV;
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALP", NULL, &polling);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALP not available\n"));
+		als->cap._ALP = 0;
+		return -ENODEV;
+	}
+	als->polling = polling;
+	return 0;
+}
+
+static int acpi_als_find_cap(struct acpi_als *als)
+{
+	acpi_handle dummy;
+
+	memset(&als->cap, 0, sizeof(als->cap));
+
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALI", &dummy)))
+		als->cap._ALI = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALC", &dummy)))
+		als->cap._ALC = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALT", &dummy)))
+		als->cap._ALT = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALR", &dummy)))
+		als->cap._ALR = 1;
+	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALP", &dummy)))
+		als->cap._ALP = 1;
+
+	if (!als->cap._ALI || !als->cap._ALR) {
+		ACPI_EXCEPTION((AE_INFO, AE_NOT_FOUND,
+				"Mandatory methods _ALI/_ALR not available"));
+		return -ENODEV;
+	}
+	return 0;
+}
+
+/* --------------------------------------------------------------------------
+				 Driver Model
+   -------------------------------------------------------------------------- */
+
+static void acpi_als_notify(struct acpi_device *device, u32 event)
+{
+	struct acpi_als *als = acpi_driver_data(device);
+
+	if (!als)
+		return;
+
+	switch (event) {
+	case ACPI_ALS_NOTIFY_ILLUMINANCE:
+		acpi_als_get_illuminance(als);
+		break;
+	case ACPI_ALS_NOTIFY_COLOR_TEMP:
+		acpi_als_get_color_temperature(als);
+		acpi_als_get_color_chromaticity(als);
+		break;
+	case ACPI_ALS_NOTIFY_RESPONSE:
+		acpi_als_get_mappings(als);
+		break;
+	default:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Unsupported event [0x%x]\n", event));
+	}
+	acpi_bus_generate_proc_event(device, event, (u32) als->illuminance);
+	acpi_bus_generate_netlink_event(device->pnp.device_class,
+					dev_name(&device->dev), event,
+					(u32) als->illuminance);
+	return;
+}
+
+static int acpi_als_add(struct acpi_device *device)
+{
+	int result = 0;
+	struct acpi_als *als = NULL;
+
+	if (!device)
+		return -EINVAL;
+
+	als = kzalloc(sizeof(struct acpi_als), GFP_KERNEL);
+	if (!als)
+		return -ENOMEM;
+
+	als->device = device;
+	strcpy(acpi_device_name(device), ACPI_ALS_DEVICE_NAME);
+	strcpy(acpi_device_class(device), ACPI_ALS_CLASS);
+	device->driver_data = als;
+
+	result = acpi_als_find_cap(als);
+	if (result)
+		goto end;
+
+	result = acpi_als_get_illuminance(als);
+	if (result)
+		goto end;
+
+	result = acpi_als_get_mappings(als);
+	if (result)
+		goto end;
+
+	acpi_als_get_color_temperature(als);
+	acpi_als_get_color_chromaticity(als);
+	acpi_als_get_polling(als);
+
+end:
+	if (result)
+		kfree(als);
+	return result;
+}
+
+static int acpi_als_resume(struct acpi_device *device)
+{
+	struct acpi_als *als;
+
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+
+	als = acpi_driver_data(device);
+
+	if (acpi_als_get_illuminance(als))
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Failed to re-evaluate"
+				  " ALS illuminance during resume\n"));
+	return 0;
+}
+
+static int acpi_als_remove(struct acpi_device *device, int type)
+{
+	struct acpi_als *als;
+
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+
+	als = acpi_driver_data(device);
+	if (!als)
+		return -EINVAL;
+
+	if (als->mappings)
+		kfree(als->mappings);
+	kfree(als);
+	return 0;
+}
+
+static int __init acpi_als_init(void)
+{
+	int result;
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	result = acpi_bus_register_driver(&acpi_als_driver);
+	if (result < 0)
+		return -ENODEV;
+	return 0;
+}
+
+static void __exit acpi_als_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_als_driver);
+	return;
+}
+
+module_init(acpi_als_init);
+module_exit(acpi_als_exit);
Index: linux-2.6/drivers/acpi/Kconfig
===================================================================
--- linux-2.6.orig/drivers/acpi/Kconfig
+++ linux-2.6/drivers/acpi/Kconfig
@@ -333,4 +333,13 @@ config ACPI_SBS
 	  To compile this driver as a module, choose M here:
 	  the modules will be called sbs and sbshc.
 
+config ACPI_ALS
+	tristate "Ambient Light Sensor driver"
+	depends on X86
+	help
+	  This driver supports the ACPI Ambient Light Sensor.
+
+	  To compile this driver as a module, choose M here:
+	  the modules will be called als.
+
 endif	# ACPI
Index: linux-2.6/drivers/acpi/Makefile
===================================================================
--- linux-2.6.orig/drivers/acpi/Makefile
+++ linux-2.6/drivers/acpi/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_ACPI_HOTPLUG_MEMORY) += acp
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
 obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
 obj-$(CONFIG_ACPI_SBS)		+= sbs.o
+obj-$(CONFIG_ACPI_ALS)		+= als.o
 
 # processor has its own "processor." module_param namespace
 processor-y			:= processor_core.o processor_throttling.o
Index: linux-2.6/Documentation/acpi/debug.txt
===================================================================
--- linux-2.6.orig/Documentation/acpi/debug.txt
+++ linux-2.6/Documentation/acpi/debug.txt
@@ -63,6 +63,7 @@ shows the supported mask values, current
     ACPI_MEMORY_DEVICE_COMPONENT    0x08000000
     ACPI_VIDEO_COMPONENT            0x10000000
     ACPI_PROCESSOR_COMPONENT        0x20000000
+    ACPI_ALS_COMPONENT              0x40000000
 
 debug_level
 -----------
Index: linux-2.6/drivers/acpi/debug.c
===================================================================
--- linux-2.6.orig/drivers/acpi/debug.c
+++ linux-2.6/drivers/acpi/debug.c
@@ -53,6 +53,7 @@ static const struct acpi_dlayer acpi_deb
 	ACPI_DEBUG_INIT(ACPI_MEMORY_DEVICE_COMPONENT),
 	ACPI_DEBUG_INIT(ACPI_VIDEO_COMPONENT),
 	ACPI_DEBUG_INIT(ACPI_PROCESSOR_COMPONENT),
+	ACPI_DEBUG_INIT(ACPI_ALS_COMPONENT),
 };
 
 static const struct acpi_dlevel acpi_debug_levels[] = {
Index: linux-2.6/include/acpi/acpi_drivers.h
===================================================================
--- linux-2.6.orig/include/acpi/acpi_drivers.h
+++ linux-2.6/include/acpi/acpi_drivers.h
@@ -49,6 +49,7 @@
 #define ACPI_MEMORY_DEVICE_COMPONENT	0x08000000
 #define ACPI_VIDEO_COMPONENT		0x10000000
 #define ACPI_PROCESSOR_COMPONENT	0x20000000
+#define ACPI_ALS_COMPONENT		0x40000000
 
 /*
  * _HID definitions

Re: [PATCH 1/3] ACPI: introduce ACPI ALS driver

[Bjorn Helgaas]

On Monday 03 August 2009 03:11:04 am Zhang Rui wrote:
> introduce ACPI ALS device driver.
> 
> ACPI spec defines ACPI Ambient Light Sensor device (hid ACPI0008),
> which provides a standard interface by which the OS may query properties
> of the ambient light environment the system is currently operating in,
> as well as the ability to detect meaningful changes in these values when the
> environment changes.
> 
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>  Documentation/acpi/debug.txt |    1 
>  drivers/acpi/Kconfig         |    9 
>  drivers/acpi/Makefile        |    1 
>  drivers/acpi/als.c           |  407 +++++++++++++++++++++++++++++++++++++++++++
>  drivers/acpi/debug.c         |    1 
>  include/acpi/acpi_drivers.h  |    1 
>  6 files changed, 420 insertions(+)
> 
> Index: linux-2.6/drivers/acpi/als.c
> ===================================================================
> --- /dev/null
> +++ linux-2.6/drivers/acpi/als.c
> @@ -0,0 +1,407 @@
> +/*
> + *  als.c - ACPI Ambient Light Sensor Driver
> + *
> + *  Copyright (C) 2009 Zhang Rui <rui.zhang@intel.com>

At HP, code we write in the course of our employment is owned by HP.
If Intel is similar, Intel is the real copyright owner, not you (of
course, I have no knowledge about your specific situation).

> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + *  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.

HP lawyers don't like the fuzziness of the "any later version" clause
(and again, I have no knowledge about any Intel preference).

> + *
> + *  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/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/types.h>
> +#include <acpi/acpi_bus.h>
> +#include <acpi/acpi_drivers.h>
> +
> +#define ACPI_ALS_CLASS			"als"
> +#define ACPI_ALS_DEVICE_NAME		"Ambient Light Sensor"
> +#define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
> +#define ACPI_ALS_NOTIFY_COLOR_TEMP	0x81
> +#define ACPI_ALS_NOTIFY_RESPONSE	0x82
> +
> +#define _COMPONENT		ACPI_ALS_COMPONENT
> +ACPI_MODULE_NAME("als");
> +
> +MODULE_AUTHOR("Zhang Rui");
> +MODULE_DESCRIPTION("ACPI Ambient Light Sensor Driver");
> +MODULE_LICENSE("GPL");
> +
> +static int acpi_als_add(struct acpi_device *device);
> +static int acpi_als_remove(struct acpi_device *device, int type);
> +static int acpi_als_resume(struct acpi_device *device);
> +static void acpi_als_notify(struct acpi_device *device, u32 event);
> +
> +static const struct acpi_device_id als_device_ids[] = {
> +	{"ACPI0008", 0},
> +	{"", 0},
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, als_device_ids);
> +
> +static struct acpi_driver acpi_als_driver = {
> +	.name = "als",
> +	.class = ACPI_ALS_CLASS,
> +	.ids = als_device_ids,
> +	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,

You shouldn't specify ACPI_DRIVER_ALL_NOTIFY_EVENTS unless you need
it, and I don't think you do, since you ignore all the system events
anyway.

> +	.ops = {
> +		.add = acpi_als_add,
> +		.resume = acpi_als_resume,
> +		.remove = acpi_als_remove,
> +		.notify = acpi_als_notify,
> +		},
> +};
> +
> +struct als_cap {
> +	u8 _ALI:1;
> +	u8 _ALC:1;
> +	u8 _ALT:1;
> +	u8 _ALR:1;
> +	u8 _ALP:1;
> +};
> +
> +struct als_mapping {
> +	int adjustment;
> +	int illuminance;
> +};
> +
> +struct acpi_als {
> +	struct acpi_device *device;
> +	struct als_cap cap;
> +	int illuminance;
> +	int chromaticity;
> +	int temperature;
> +	int polling;
> +	int count;
> +	struct als_mapping *mappings;
> +};
> +
> +#define ALS_INVALID_VALUE_LOW		0
> +#define ALS_INVALID_VALUE_HIGH		-1
> +
> +/* --------------------------------------------------------------------------
> +		Ambient Light Sensor device Management
> +   -------------------------------------------------------------------------- */
> +
> +/*
> + * acpi_als_get_illuminance - get the current ambient light illuminance
> + */
> +static int acpi_als_get_illuminance(struct acpi_als *als)
> +{
> +	acpi_status status;
> +	unsigned long long illuminance;
> +
> +	status =
> +	    acpi_evaluate_integer(als->device->handle, "_ALI", NULL,
> +				  &illuminance);
> +	if (ACPI_FAILURE(status)) {
> +		ACPI_EXCEPTION((AE_INFO, status,
> +				"Error reading ALS illuminance"));
> +		als->illuminance = ALS_INVALID_VALUE_LOW;
> +		return -ENODEV;
> +	}
> +	als->illuminance = illuminance;
> +	return 0;
> +}
> +
> +/*
> + * acpi_als_get_color_chromaticity - get the ambient light color chromaticity
> + */
> +static int acpi_als_get_color_chromaticity(struct acpi_als *als)
> +{
> +	acpi_status status;
> +	unsigned long long chromaticity;
> +
> +	if (!als->cap._ALC)
> +		return -ENODEV;

Is there real benefit in keeping track of the als_cap structure?
What would be lost if you merely did this instead:

	status = acpi_evaluate_integer(als->device->handle, "_ALC", NULL,
				       &chromaticity);
	if (ACPI_FAILURE(status))
		return -ENODEV;

That is, I think it would *work* if we never cached the cap._ALC
value and just always attempted to evaluate _ALC.  If the BIOS doesn't
implement _ALS, the evaluation would always fail, of course, and
that's slightly more expensive than just checking the cached cap._ALC
bit.  But I don't think this is a performance path, and caching always
adds code complexity and the niggling worries about whether the cache
is correct.

> +	status =
> +	    acpi_evaluate_integer(als->device->handle, "_ALC", NULL,
> +				  &chromaticity);
> +	if (ACPI_FAILURE(status)) {
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALC not available\n"));
> +		als->cap._ALC = 0;
> +		return -ENODEV;
> +	}
> +	als->chromaticity = chromaticity;
> +	return 0;
> +}
> +
> +/*
> + * acpi_als_get_color_temperature - get the ambient light color temperature
> + */
> +static int acpi_als_get_color_temperature(struct acpi_als *als)
> +{
> +	acpi_status status;
> +	unsigned long long temperature;
> +
> +	if (!als->cap._ALT)
> +		return -ENODEV;
> +	status =
> +	    acpi_evaluate_integer(als->device->handle, "_ALT", NULL,
> +				  &temperature);
> +	if (ACPI_FAILURE(status)) {
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALT not available\n"));
> +		als->cap._ALT = 0;
> +		return -ENODEV;
> +	}
> +	als->temperature = temperature;
> +	return 0;
> +}
> +
> +/*
> + * acpi_als_get_mappings - get the ALS illuminance mappings
> + *
> + * Return a package of ALS illuminance to display adjustment mappings
> + * that can be used by OS to calibrate its ambient light policy
> + * for a given sensor configuration.
> + */
> +static int acpi_als_get_mappings(struct acpi_als *als)
> +{
> +	int result = 0;
> +	acpi_status status = AE_OK;
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *alr = NULL;

No need to initialize "status" or "alr" here.

> +	int i, j;
> +
> +	status =
> +	    acpi_evaluate_object(als->device->handle, "_ALR", NULL, &buffer);
> +	if (ACPI_FAILURE(status)) {
> +		ACPI_EXCEPTION((AE_INFO, status, "Error reading ALS mappings"));
> +		return -ENODEV;
> +	}
> +
> +	alr = buffer.pointer;
> +	if (!alr || (alr->type != ACPI_TYPE_PACKAGE)) {
> +		printk(KERN_ERR PREFIX "Invalid _ALR data\n");
> +		result = -EFAULT;
> +		goto end;
> +	}
> +
> +	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d illuminance mappings\n",
> +			  alr->package.count));
> +
> +	als->count = alr->package.count;
> +	als->mappings =
> +	    kmalloc(sizeof(struct als_mapping) * als->count, GFP_KERNEL);
> +	if (!als->mappings) {
> +		result = -ENOMEM;
> +		goto end;
> +	}
> +
> +	for (i = 0, j = 0; i < als->count; i++) {
> +		struct als_mapping *mapping = &(als->mappings[j]);
> +		union acpi_object *element = &(alr->package.elements[i]);
> +
> +		if (element->type != ACPI_TYPE_PACKAGE)
> +			continue;
> +
> +		if (element->package.count != 2)
> +			continue;
> +
> +		if (element->package.elements[0].type != ACPI_TYPE_INTEGER ||
> +		    element->package.elements[1].type != ACPI_TYPE_INTEGER)
> +			continue;
> +
> +		mapping->adjustment =
> +		    element->package.elements[0].integer.value;
> +		mapping->illuminance =
> +		    element->package.elements[1].integer.value;
> +		j++;
> +
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Mapping [%d]: "
> +				  "adjuestment [%d] illuminance[%d]\n",
> +				  i, mapping->adjustment,
> +				  mapping->illuminance));
> +	}
> +
> +end:
> +	kfree(buffer.pointer);
> +	return result;
> +}
> +
> +/*
> + * acpi_als_get_polling - get the current ambient light illuminance
> + */
> +static int acpi_als_get_polling(struct acpi_als *als)
> +{
> +	acpi_status status;
> +	unsigned long long polling;
> +
> +	if (!als->cap._ALP)
> +		return -ENODEV;
> +	status =
> +	    acpi_evaluate_integer(als->device->handle, "_ALP", NULL, &polling);
> +	if (ACPI_FAILURE(status)) {
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALP not available\n"));
> +		als->cap._ALP = 0;
> +		return -ENODEV;
> +	}
> +	als->polling = polling;
> +	return 0;
> +}
> +
> +static int acpi_als_find_cap(struct acpi_als *als)
> +{
> +	acpi_handle dummy;
> +
> +	memset(&als->cap, 0, sizeof(als->cap));
> +
> +	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALI", &dummy)))
> +		als->cap._ALI = 1;
> +	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALC", &dummy)))
> +		als->cap._ALC = 1;
> +	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALT", &dummy)))
> +		als->cap._ALT = 1;
> +	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALR", &dummy)))
> +		als->cap._ALR = 1;
> +	if (ACPI_SUCCESS(acpi_get_handle(als->device->handle, "_ALP", &dummy)))
> +		als->cap._ALP = 1;
> +
> +	if (!als->cap._ALI || !als->cap._ALR) {
> +		ACPI_EXCEPTION((AE_INFO, AE_NOT_FOUND,
> +				"Mandatory methods _ALI/_ALR not available"));
> +		return -ENODEV;
> +	}
> +	return 0;
> +}
> +
> +/* --------------------------------------------------------------------------
> +				 Driver Model
> +   -------------------------------------------------------------------------- */
> +
> +static void acpi_als_notify(struct acpi_device *device, u32 event)
> +{
> +	struct acpi_als *als = acpi_driver_data(device);
> +
> +	if (!als)
> +		return;

No need to check for a null pointer here.

> +
> +	switch (event) {
> +	case ACPI_ALS_NOTIFY_ILLUMINANCE:
> +		acpi_als_get_illuminance(als);
> +		break;
> +	case ACPI_ALS_NOTIFY_COLOR_TEMP:
> +		acpi_als_get_color_temperature(als);
> +		acpi_als_get_color_chromaticity(als);
> +		break;
> +	case ACPI_ALS_NOTIFY_RESPONSE:
> +		acpi_als_get_mappings(als);
> +		break;
> +	default:
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
> +				  "Unsupported event [0x%x]\n", event));
> +	}
> +	acpi_bus_generate_proc_event(device, event, (u32) als->illuminance);
> +	acpi_bus_generate_netlink_event(device->pnp.device_class,
> +					dev_name(&device->dev), event,
> +					(u32) als->illuminance);
> +	return;

No need for a "return;" statement here.

> +}
> +
> +static int acpi_als_add(struct acpi_device *device)
> +{
> +	int result = 0;
> +	struct acpi_als *als = NULL;

No need to initialize these.

> +
> +	if (!device)
> +		return -EINVAL;

No need to check for a null pointer.

> +
> +	als = kzalloc(sizeof(struct acpi_als), GFP_KERNEL);
> +	if (!als)
> +		return -ENOMEM;
> +
> +	als->device = device;
> +	strcpy(acpi_device_name(device), ACPI_ALS_DEVICE_NAME);
> +	strcpy(acpi_device_class(device), ACPI_ALS_CLASS);
> +	device->driver_data = als;
> +
> +	result = acpi_als_find_cap(als);
> +	if (result)
> +		goto end;
> +
> +	result = acpi_als_get_illuminance(als);
> +	if (result)
> +		goto end;
> +
> +	result = acpi_als_get_mappings(als);
> +	if (result)
> +		goto end;
> +
> +	acpi_als_get_color_temperature(als);
> +	acpi_als_get_color_chromaticity(als);
> +	acpi_als_get_polling(als);
> +
> +end:
> +	if (result)
> +		kfree(als);
> +	return result;
> +}
> +
> +static int acpi_als_resume(struct acpi_device *device)
> +{
> +	struct acpi_als *als;
> +
> +	if (!device || !acpi_driver_data(device))
> +		return -EINVAL;

You don't need these checks.

> +
> +	als = acpi_driver_data(device);

This can go on the same line as the "als" definition.

> +
> +	if (acpi_als_get_illuminance(als))
> +		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Failed to re-evaluate"
> +				  " ALS illuminance during resume\n"));
> +	return 0;
> +}
> +
> +static int acpi_als_remove(struct acpi_device *device, int type)
> +{
> +	struct acpi_als *als;
> +
> +	if (!device || !acpi_driver_data(device))
> +		return -EINVAL;

See above.

> +
> +	als = acpi_driver_data(device);
> +	if (!als)
> +		return -EINVAL;

No need to check for a null pointer here.

> +
> +	if (als->mappings)
> +		kfree(als->mappings);
> +	kfree(als);
> +	return 0;
> +}
> +
> +static int __init acpi_als_init(void)
> +{
> +	int result;
> +
> +	if (acpi_disabled)
> +		return -ENODEV;

No need to check "acpi_disabled" here.  acpi_bus_register_driver()
already does that for you.

> +
> +	result = acpi_bus_register_driver(&acpi_als_driver);
> +	if (result < 0)
> +		return -ENODEV;
> +	return 0;
> +}
> +
> +static void __exit acpi_als_exit(void)
> +{
> +	acpi_bus_unregister_driver(&acpi_als_driver);
> +	return;
> +}
> +
> +module_init(acpi_als_init);
> +module_exit(acpi_als_exit);
> Index: linux-2.6/drivers/acpi/Kconfig
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/Kconfig
> +++ linux-2.6/drivers/acpi/Kconfig
> @@ -333,4 +333,13 @@ config ACPI_SBS
>  	  To compile this driver as a module, choose M here:
>  	  the modules will be called sbs and sbshc.
>  
> +config ACPI_ALS
> +	tristate "Ambient Light Sensor driver"
> +	depends on X86

There's nothing x86-specific here, though I grant you there
aren't going to be many ia64 boxes with ambient light sensors :-)

> +	help
> +	  This driver supports the ACPI Ambient Light Sensor.
> +
> +	  To compile this driver as a module, choose M here:
> +	  the modules will be called als.
> +
>  endif	# ACPI
> Index: linux-2.6/drivers/acpi/Makefile
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/Makefile
> +++ linux-2.6/drivers/acpi/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_ACPI_HOTPLUG_MEMORY) += acp
>  obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
>  obj-$(CONFIG_ACPI_SBS)		+= sbshc.o
>  obj-$(CONFIG_ACPI_SBS)		+= sbs.o
> +obj-$(CONFIG_ACPI_ALS)		+= als.o
>  
>  # processor has its own "processor." module_param namespace
>  processor-y			:= processor_core.o processor_throttling.o
> Index: linux-2.6/Documentation/acpi/debug.txt
> ===================================================================
> --- linux-2.6.orig/Documentation/acpi/debug.txt
> +++ linux-2.6/Documentation/acpi/debug.txt
> @@ -63,6 +63,7 @@ shows the supported mask values, current
>      ACPI_MEMORY_DEVICE_COMPONENT    0x08000000
>      ACPI_VIDEO_COMPONENT            0x10000000
>      ACPI_PROCESSOR_COMPONENT        0x20000000
> +    ACPI_ALS_COMPONENT              0x40000000

Wow, thanks for updating this list, too!

>  
>  debug_level
>  -----------
> Index: linux-2.6/drivers/acpi/debug.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/debug.c
> +++ linux-2.6/drivers/acpi/debug.c
> @@ -53,6 +53,7 @@ static const struct acpi_dlayer acpi_deb
>  	ACPI_DEBUG_INIT(ACPI_MEMORY_DEVICE_COMPONENT),
>  	ACPI_DEBUG_INIT(ACPI_VIDEO_COMPONENT),
>  	ACPI_DEBUG_INIT(ACPI_PROCESSOR_COMPONENT),
> +	ACPI_DEBUG_INIT(ACPI_ALS_COMPONENT),
>  };
>  
>  static const struct acpi_dlevel acpi_debug_levels[] = {
> Index: linux-2.6/include/acpi/acpi_drivers.h
> ===================================================================
> --- linux-2.6.orig/include/acpi/acpi_drivers.h
> +++ linux-2.6/include/acpi/acpi_drivers.h
> @@ -49,6 +49,7 @@
>  #define ACPI_MEMORY_DEVICE_COMPONENT	0x08000000
>  #define ACPI_VIDEO_COMPONENT		0x10000000
>  #define ACPI_PROCESSOR_COMPONENT	0x20000000
> +#define ACPI_ALS_COMPONENT		0x40000000
>  
>  /*
>   * _HID definitions
> 
> 
> --
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

Re: [PATCH 1/3] ACPI: introduce ACPI ALS driver

[Len Brown]

For the record, new code from Intel OTC  should have the GPL below.

It is optional to add your own name on the copyright
in addition to the corporate one.  In general, I recommend
against it -- because it serves just to get random e-mail
sent to your (eventually stale) e-mail address --
and the people who have useful feedback on your code
already know how to send you e-mail.

cheers,
-Len


/*
 * <insert one-line description of what the program does>
 * Copyright (c) 2009, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */