Introduce ALS sysfs class device.
ALS sysfs class device provides a standard sysfs interface
for Ambient Light Sensor devices.
Only two sysfs I/F are introduced currently.
/sys/class/als/alsX/illuminance:
indicates the amount of light incident upon a specified surface area.
/sys/class/als/alsX/mappings:
exports ambient light illuminance to display luminance mappings
that can be used by an OS to calibrate its ambient light policy
for a given sensor configuration.
The OS can use this information to extrapolate an ALS response curve
- noting that these values may be treated differently depending on the
OS implementation but should be used in some form to calibrate ALS policy.
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
---
drivers/Kconfig | 2
drivers/Makefile | 1
drivers/als/Kconfig | 10 ++
drivers/als/Makefile | 5 +
drivers/als/als_sys.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/als_sys.h | 55 ++++++++++++
6 files changed, 279 insertions(+)
Index: linux-2.6/drivers/Kconfig
===================================================================
--- linux-2.6.orig/drivers/Kconfig
+++ linux-2.6/drivers/Kconfig
@@ -62,6 +62,8 @@ source "drivers/power/Kconfig"
source "drivers/hwmon/Kconfig"
+source "drivers/als/Kconfig"
+
source "drivers/thermal/Kconfig"
source "drivers/watchdog/Kconfig"
Index: linux-2.6/drivers/Makefile
===================================================================
--- linux-2.6.orig/drivers/Makefile
+++ linux-2.6/drivers/Makefile
@@ -76,6 +76,7 @@ obj-$(CONFIG_PPS) += pps/
obj-$(CONFIG_W1) += w1/
obj-$(CONFIG_POWER_SUPPLY) += power/
obj-$(CONFIG_HWMON) += hwmon/
+obj-$(CONFIG_ALS) += als/
obj-$(CONFIG_THERMAL) += thermal/
obj-$(CONFIG_WATCHDOG) += watchdog/
obj-$(CONFIG_PHONE) += telephony/
Index: linux-2.6/drivers/als/Kconfig
===================================================================
--- /dev/null
+++ linux-2.6/drivers/als/Kconfig
@@ -0,0 +1,10 @@
+#
+# Ambient Light Sensor sysfs device configuration
+#
+
+menuconfig ALS
+ tristate "Ambient Light Sensor sysfs device"
+ help
+ This framework provides a generic sysfs I/F for Ambient Light
+ Sensor devices.
+ If you want this support, you should say Y or M here.
Index: linux-2.6/drivers/als/Makefile
===================================================================
--- /dev/null
+++ linux-2.6/drivers/als/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for sensor chip drivers.
+#
+
+obj-$(CONFIG_ALS) += als_sys.o
Index: linux-2.6/drivers/als/als_sys.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/als/als_sys.c
@@ -0,0 +1,206 @@
+/*
+ * als_sys.c - Ambient Light Sensor Sysfs support.
+ *
+ * Copyright (C) 2009 Intel Corp
+ * Copyright (C) 2009 Zhang Rui <rui.zhang@xxxxxxxxx>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * 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/device.h>
+#include <linux/err.h>
+#include <linux/als_sys.h>
+
+MODULE_AUTHOR("Zhang Rui");
+MODULE_DESCRIPTION("Ambient Light Sensor sysfs support");
+MODULE_LICENSE("GPL");
+
+#define PREFIX "ALS: "
+
+/* sys I/F for Ambient Light Sensor */
+
+#define to_als_device(dev) container_of(dev, struct als_device, device)
+
+static ssize_t
+desc_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct als_device *als = to_als_device(dev);
+
+ return sprintf(buf, "%s\n", als->desc ? als->desc : "N/A");
+}
+
+static ssize_t
+illuminance_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct als_device *als = to_als_device(dev);
+ int result;
+
+ if (!als->ops->get_illuminance)
+ return -EPERM;
+
+ result = als->ops->get_illuminance(als);
+ if (result)
+ return result;
+
+ if (!als->illuminance)
+ return sprintf(buf, "Illuminance below the supported range\n");
+ else if (als->illuminance == -1)
+ return sprintf(buf, "Illuminance above the supported range\n");
+ else if (als->illuminance < -1)
+ return -ERANGE;
+ else
+ return sprintf(buf, "%d\n", als->illuminance);
+}
+
+static ssize_t
+mappings_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct als_device *als = to_als_device(dev);
+ int count;
+ int result;
+
+ if (!als->ops->get_mappings)
+ return -EPERM;
+
+ result = als->ops->get_mappings(als);
+ if (result)
+ return result;
+
+ result = sprintf(buf, "Illuminance Adjustment\n");
+ for (count = 0; count < als->count; count++) {
+ result += sprintf(buf + result, "%11d\t",
+ als->mappings[count].illuminance);
+ result += sprintf(buf + result, "%10d\n",
+ als->mappings[count].adjustment);
+ }
+
+ return result;
+}
+
+static DEVICE_ATTR(desc, 0444, desc_show, NULL);
+static DEVICE_ATTR(illuminance, 0444, illuminance_show, NULL);
+static DEVICE_ATTR(mappings, 0444, mappings_show, NULL);
+
+static void als_release(struct device *dev)
+{
+ struct als_device *als = to_als_device(dev);
+
+ if (als->desc)
+ kfree(als->desc);
+ kfree(als);
+}
+
+static struct class als_class = {
+ .name = "als",
+ .dev_release = als_release,
+};
+
+/**
+ * als_device_register - register a new Ambient Light Sensor class device
+ * @ops: standard ALS devices callbacks.
+ * @devdata: device private data.
+ */
+struct als_device *als_device_register(struct als_device_ops *ops,
+ char *desc, void *devdata)
+{
+ struct als_device *als;
+ static int als_id;
+ int result;
+
+ if (!ops || !ops->get_illuminance || !ops->get_mappings)
+ return ERR_PTR(-EINVAL);
+
+ als = kzalloc(sizeof(struct als_device), GFP_KERNEL);
+ if (!als)
+ return ERR_PTR(-ENOMEM);
+
+ als->ops = ops;
+ als->device.class = &als_class;
+ als->devdata = devdata;
+ if (desc) {
+ als->desc = kzalloc(strlen(desc), GFP_KERNEL);
+ if (!als->desc) {
+ kfree(als);
+ return ERR_PTR(-ENOMEM);
+ }
+ strcpy(als->desc, desc);
+ }
+ als->id = als_id++;
+ dev_set_name(&als->device, "als%d", als->id);
+ result = device_register(&als->device);
+ if (result) {
+ if (als->desc)
+ kfree(als->desc);
+ kfree(als);
+ return ERR_PTR(result);
+ }
+
+ /* sys I/F */
+ result = device_create_file(&als->device, &dev_attr_illuminance);
+ if (result)
+ goto unregister_device;
+
+ result = device_create_file(&als->device, &dev_attr_mappings);
+ if (result)
+ goto unregister_device;
+
+ result = device_create_file(&als->device, &dev_attr_desc);
+ if (result)
+ goto unregister_device;
+
+ return als;
+
+unregister_device:
+ device_unregister(&als->device);
+ return ERR_PTR(result);
+}
+
+EXPORT_SYMBOL(als_device_register);
+
+/**
+ * als_device_unregister - removes the registered ALS device
+ * @als: the ALS device to remove.
+ */
+void als_device_unregister(struct als_device *als)
+{
+ if (!als)
+ return;
+
+ device_remove_file(&als->device, &dev_attr_desc);
+ device_remove_file(&als->device, &dev_attr_mappings);
+ device_remove_file(&als->device, &dev_attr_illuminance);
+
+ device_unregister(&als->device);
+ return;
+}
+
+EXPORT_SYMBOL(als_device_unregister);
+
+static int __init als_init(void)
+{
+ return class_register(&als_class);
+}
+
+static void __exit als_exit(void)
+{
+ class_unregister(&als_class);
+}
+
+subsys_initcall(als_init);
+module_exit(als_exit);
Index: linux-2.6/include/linux/als_sys.h
===================================================================
--- /dev/null
+++ linux-2.6/include/linux/als_sys.h
@@ -0,0 +1,55 @@
+/*
+ * als.h ($Revision: 0 $)
+ *
+ * Copyright (C) 2009 Intel Corp
+ * Copyright (C) 2009 Zhang Rui <rui.zhang@xxxxxxxxx>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * 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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef __ALS_SYS_H__
+#define __ALS_SYS_H__
+
+#include <linux/device.h>
+
+struct als_device;
+
+struct als_mapping {
+ int illuminance;
+ int adjustment;
+};
+
+struct als_device_ops {
+ int (*get_mappings) (struct als_device *);
+ int (*get_illuminance) (struct als_device *);
+};
+
+struct als_device {
+ int id;
+ int illuminance;
+ struct device device;
+ struct als_device_ops *ops;
+ void *devdata;
+ int count;
+ struct als_mapping *mappings;
+ char *desc;
+};
+
+struct als_device *als_device_register(struct als_device_ops *, char *, void *);
+void als_device_unregister(struct als_device *);
+
+#endif /* __ALS_SYS_H__ */
--
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