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Subject[PATCH V5 1/2] introduce ALS sysfs class
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Date

Introduce ALS sysfs class.

ALS sysfs class provides a standard sysfs interface for
Ambient Light Sensor devices.

please read Documentation/ABI/testing/sysfs-class-als for
detailed sysfs designs.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
Documentation/ABI/testing/sysfs-class-als | 32 ++++
MAINTAINERS | 6
drivers/Kconfig | 2
drivers/Makefile | 1
drivers/als/Kconfig | 10 +
drivers/als/Makefile | 5
drivers/als/als_sys.c | 220 ++++++++++++++++++++++++++++++
include/linux/als_sys.h | 55 +++++++
8 files changed, 331 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 interface 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 Ambient Light Sensor device 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 +1,220 @@
+/*
+ * als_sys.c - Ambient Light Sensor Sysfs support.
+ *
+ * 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/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");
+
+static int als_get_adjustment(struct als_device *, int, int *);
+
+/* 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 illuminance;
+ int result;
+
+ result = als->ops->get_illuminance(als, &illuminance);
+ if (result)
+ return result;
+
+ if (!illuminance)
+ return sprintf(buf, "Illuminance below the supported range\n");
+ else if (illuminance == -1)
+ return sprintf(buf, "Illuminance above the supported range\n");
+ else if (illuminance < -1)
+ return -ERANGE;
+ else
+ return sprintf(buf, "%d\n", illuminance);
+}
+
+static ssize_t
+adjustment_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct als_device *als = to_als_device(dev);
+ int illuminance, adjustment;
+ int result;
+
+ result = als->ops->get_illuminance(als, &illuminance);
+ if (result)
+ return result;
+
+ if (illuminance < 0 && illuminance != -1)
+ return sprintf(buf, "Current illuminance invalid\n");
+
+ result = als_get_adjustment(als, illuminance, &adjustment);
+ if (result)
+ return result;
+
+ return sprintf(buf, "%d%%\n", adjustment);
+}
+
+static struct device_attribute als_attrs[] = {
+ __ATTR(desc, 0444, desc_show, NULL),
+ __ATTR(illuminance, 0444, illuminance_show, NULL),
+ __ATTR(display_adjustment, 0444, adjustment_show, NULL),
+ __ATTR_NULL,
+};
+
+static void als_release(struct device *dev)
+{
+ struct als_device *als = to_als_device(dev);
+
+ kfree(als->desc);
+ kfree(als);
+}
+
+static struct class als_class = {
+ .name = "als",
+ .dev_release = als_release,
+ .dev_attrs = als_attrs,
+};
+
+static int als_get_adjustment(struct als_device *als, int illuminance,
+ int *adjustment)
+{
+ int lux_high, lux_low, adj_high, adj_low;
+ int i;
+
+ if (!als->mappings)
+ return -EINVAL;
+
+ if (illuminance == -1
+ || illuminance > als->mappings[als->count].illuminance)
+ illuminance = als->mappings[als->count].illuminance;
+ else if (illuminance < als->mappings[0].illuminance)
+ illuminance = als->mappings[0].illuminance;
+
+ for (i = 0; i < als->count; i++) {
+ if (illuminance == als->mappings[i].illuminance) {
+ *adjustment = als->mappings[i].adjustment;
+ return 0;
+ }
+
+ if (illuminance > als->mappings[i].illuminance)
+ continue;
+
+ lux_high = als->mappings[i].illuminance;
+ lux_low = als->mappings[i - 1].illuminance;
+ adj_high = als->mappings[i].adjustment;
+ adj_low = als->mappings[i - 1].adjustment;
+
+ *adjustment =
+ ((adj_high - adj_low) / (lux_high -
+ lux_low)) * (illuminance -
+ lux_low) + adj_low;
+ return 0;
+ }
+ return -EINVAL;
+}
+
+/**
+ * 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 = -ENOMEM;
+
+ if (!ops || !ops->get_illuminance)
+ 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;
+ als->id = als_id++;
+ if (desc) {
+ als->desc = kzalloc(strlen(desc), GFP_KERNEL);
+ if (!als->desc)
+ goto err;
+ strcpy(als->desc, desc);
+ }
+ dev_set_name(&als->device, "als%d", als->id);
+ result = device_register(&als->device);
+ if (result)
+ goto err;
+
+ if (ops->update_mappings) {
+ result = ops->update_mappings(als);
+ if (result) {
+ device_unregister(&als->device);
+ goto err;
+ }
+ }
+ return als;
+
+err:
+ kfree(als->desc);
+ kfree(als);
+ 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)
+{
+ device_unregister(&als->device);
+}
+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
+ *
+ * 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.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#ifndef __ALS_SYS_H__
+#define __ALS_SYS_H__
+
+#include <linux/device.h>
+
+struct als_device;
+
+struct als_device_ops {
+ int (*get_illuminance) (struct als_device *, int *);
+ int (*update_mappings) (struct als_device *);
+};
+
+struct als_mapping {
+ int illuminance;
+ int adjustment;
+};
+
+struct als_device {
+ int id;
+ int illuminance;
+ struct device device;
+ struct als_device_ops *ops;
+ void *devdata;
+ char *desc;
+ int count;
+ struct als_mapping *mappings;
+};
+
+struct als_device *als_device_register(struct als_device_ops *, char *, void *);
+void als_device_unregister(struct als_device *);
+
+#endif /* __ALS_SYS_H__ */
Index: linux-2.6/Documentation/ABI/testing/sysfs-class-als
===================================================================
--- /dev/null
+++ linux-2.6/Documentation/ABI/testing/sysfs-class-als
@@ -0,0 +1,32 @@
+What: /sys/class/als/als[0-N]/desc
+Date: Aug. 2009
+KernelVersion: 2.6.32
+Contact: Zhang Rui <rui.zhang@intel.com>
+Description: Strings which descibes the current Ambient Light Sensor
+ device. This is given by native ALS driver as part of
+ registration. e.g: "acpi_als" for ACPI ALS devices.
+ RO
+
+What: /sys/class/als/als[0-N]/illuminance
+Date: Aug. 2009
+KernelVersion: 2.6.32
+Contact: Zhang Rui <rui.zhang@intel.com>
+Description: Current Ambient Light Illuminance reported by
+ native ALS driver
+ Unit: lux (lumens per square meter)
+ RO
+
+What: /sys/class/als/als[0-N]/display_adjustment
+Date: Aug. 2009
+KernelVersion: 2.6.32
+Contact: Zhang Rui <rui.zhang@intel.com>
+Description: a relative percentages in order simplify the means
+ by which these adjustments are applied in lieu of
+ changes to the user’s display brightness preference.
+ A value of 100% is used to indicate no display
+ brightness adjustment.
+ Values less than 100% indicate a negative adjustment
+ (dimming); values greater than 100% indicate a positive
+ adjustment (brightening).
+ RO
+
Index: linux-2.6/MAINTAINERS
===================================================================
--- linux-2.6.orig/MAINTAINERS
+++ linux-2.6/MAINTAINERS
@@ -399,6 +399,12 @@ S: Maintained for 2.4; PCI support for 2
L: linux-alpha@vger.kernel.org
F: arch/alpha/

+AMBIENT LIGHT SENSOR
+M: Zhang Rui <rui.zhang@intel.com>
+S: Supported
+F: include/linux/als_sys.h
+F: drivers/als/
+
AMD GEODE CS5536 USB DEVICE CONTROLLER DRIVER
M: Thomas Dahlmann <dahlmann.thomas@arcor.de>
L: linux-geode@lists.infradead.org (moderated for non-subscribers)

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