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 device driver.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Documentation/acpi/debug.txt

@@ -63,6 +63,7 @@ shows the supported mask values, currently these:
     ACPI_MEMORY_DEVICE_COMPONENT    0x08000000
     ACPI_VIDEO_COMPONENT            0x10000000
     ACPI_PROCESSOR_COMPONENT        0x20000000
+    ACPI_ALS_COMPONENT              0x40000000
 
 debug_level
 -----------

MAINTAINERS

@@ -234,6 +234,13 @@ F:	drivers/acpi/
 F:	drivers/pnp/pnpacpi/
 F:	include/linux/acpi.h
 
+ACPI AMBIENT LIGHT SENSOR DRIVER
+M:	Zhang Rui <rui.zhang@intel.com>
+L:	linux-acpi@vger.kernel.org
+W:	http://www.lesswatts.org/projects/acpi/
+S:	Supported
+F:	drivers/acpi/als.c
+
 ACPI BATTERY DRIVERS
 M:	Alexey Starikovskiy <astarikovskiy@suse.de>
 L:	linux-acpi@vger.kernel.org

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"
+	select ALS
+	help
+	  This driver supports the ACPI Ambient Light Sensor.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called als.
+
 endif	# ACPI

drivers/acpi/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_ACPI_HOTPLUG_MEMORY) += acpi_memhotplug.o
 obj-$(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

drivers/acpi/als.c

+/*
+ *  als.c - ACPI Ambient Light Sensor Driver
+ *
+ *  Copyright (C) 2009 Intel Corp
+ *  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; 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/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/als_sys.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 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,
+	.ops = {
+		.add = acpi_als_add,
+		.remove = acpi_als_remove,
+		.notify = acpi_als_notify,
+		},
+};
+
+struct acpi_als {
+	struct acpi_device *device;
+	struct als_device *als_sys;
+	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;
+
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALC", NULL,
+				  &chromaticity);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALC not available\n"));
+		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;
+
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALT", NULL,
+				  &temperature);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALT not available\n"));
+		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;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *alr;
+	int i, j;
+
+	/* Free the old 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 a recommended polling frequency
+ * 			  for the Ambient Light Sensor device
+ */
+static int acpi_als_get_polling(struct acpi_als *als)
+{
+	acpi_status status;
+	unsigned long long polling;
+
+	status =
+	    acpi_evaluate_integer(als->device->handle, "_ALP", NULL, &polling);
+	if (ACPI_FAILURE(status)) {
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "_ALP not available\n"));
+		return -ENODEV;
+	}
+
+	als->polling = polling;
+	return 0;
+}
+
+/*------------------------------------------------------------------------
+ *                                ALS sysfs I/F
+ *------------------------------------------------------------------------ */
+
+static int get_illuminance(struct als_device *als_sys, int *illuminance)
+{
+	struct acpi_als *als = als_sys->devdata;
+	int result;
+
+	result = acpi_als_get_illuminance(als);
+	if (!result)
+		*illuminance = als->illuminance;
+	return result;
+}
+
+static int update_mappings(struct als_device *als_sys)
+{
+	struct acpi_als *als = als_sys->devdata;
+	int result;
+
+	result = acpi_als_get_mappings(als);
+	if (result)
+		return result;
+
+	als_sys->mappings = als->mappings;
+	als_sys->count = als->count;
+
+	return 0;
+}
+
+struct als_device_ops acpi_als_ops = {
+	.get_illuminance = get_illuminance,
+	.update_mappings = update_mappings,
+};
+
+/* --------------------------------------------------------------------------
+				 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:
+		update_mappings(als->als_sys);
+		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);
+}
+
+static int acpi_als_add(struct acpi_device *device)
+{
+	int result;
+	struct acpi_als *als;
+
+	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_get_illuminance(als);
+	if (result)
+		goto err;
+
+	result = acpi_als_get_mappings(als);
+	if (result)
+		goto err;
+
+	acpi_als_get_color_temperature(als);
+	acpi_als_get_color_chromaticity(als);
+	acpi_als_get_polling(als);
+
+	als->als_sys = als_device_register(&acpi_als_ops, "acpi_als", als);
+	if (IS_ERR(als->als_sys)) {
+		result = PTR_ERR(als->als_sys);
+		als->als_sys = NULL;
+		goto err;
+	}
+
+	result = sysfs_create_link(&als->als_sys->device.kobj,
+				&device->dev.kobj, "device");
+	if (result) {
+		printk(KERN_ERR PREFIX "Create sysfs link\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	if (als->als_sys)
+		als_device_unregister(als->als_sys);
+	kfree(als->mappings);
+	kfree(als);
+	return result;
+}
+
+static int acpi_als_remove(struct acpi_device *device, int type)
+{
+	struct acpi_als *als = acpi_driver_data(device);
+
+	sysfs_remove_link(&als->als_sys->device.kobj, "device");
+	als_device_unregister(als->als_sys);
+	kfree(als->mappings);
+	kfree(als);
+	return 0;
+}
+
+static int __init acpi_als_init(void)
+{
+	return acpi_bus_register_driver(&acpi_als_driver);
+}
+
+static void __exit acpi_als_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_als_driver);
+}
+
+module_init(acpi_als_init);
+module_exit(acpi_als_exit);

drivers/acpi/debug.c

@@ -53,6 +53,7 @@ static const struct acpi_dlayer acpi_debug_layers[] = {
 	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[] = {

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