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Date: Wed, 23 Sep 2009 09:26:32 +0800
From: Zhang Rui <rui.zhang@...el.com>
To: Jonathan Cameron <jic23@....ac.uk>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-acpi <linux-acpi@...r.kernel.org>,
Jean Delvare <khali@...ux-fr.org>,
"alan@...ux.intel.com" <alan@...ux.intel.com>,
"Cory T. Tusar" <ctusar@...eon-central.com>,
"Trisal, Kalhan" <kalhan.trisal@...el.com>,
Len Brown <lenb@...nel.org>, Pavel Machek <pavel@....cz>
Subject: Re: [RFC] [PATCH 2/2] ACPI: introduce ACPI ALS device driver
On Tue, 2009-09-22 at 20:55 +0800, Jonathan Cameron wrote:
> Note I have no familiarity at all with the acpi side of things!
> Other than a few queries, this looks fine to me.
>
> Jonathan
> > 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@...el.com>
> > ---
> > Documentation/acpi/debug.txt | 1
> > MAINTAINERS | 7 +
> > drivers/acpi/Kconfig | 9 +
> > drivers/acpi/Makefile | 1
> > drivers/acpi/als.c | 223 +++++++++++++++++++++++++++++++++++++++++++
> > drivers/acpi/debug.c | 1
> > include/acpi/acpi_drivers.h | 1
> > 7 files changed, 243 insertions(+)
> >
> > Index: linux-2.6/drivers/acpi/als.c
> > +
> > +/* --------------------------------------------------------------------------
> > + 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:
> > + /*
> > + * TODO:
> > + * re-evalute the color temperature and chromaticity
> > + */
> > + break;
> > + case ACPI_ALS_NOTIFY_RESPONSE:
> > + /*
> > + * TODO:
> > + * update the Ambient Light Illuminance to
> > + * Display Luminance Adjustment Mappings
> > + */
> > + 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;
> Are there any plausible race conditions associated with doing the allocation this way?
well, theoretically, yes.
simultaneous add calls may happen in hotplug case, but I don't think an
ACPI ALS device supports hotplug.
> This variable may need some protection. (I'm guessing acpi may prevent simultaneous
> add calls?)
> > + static int als_id;
> > + char name[10];
> > + struct acpi_als *als;
> > +
> > + if (unlikely(als_id >= 10)) {
> > + printk(KERN_WARNING PREFIX "Too many ALS device found\n");
> > + return -ENODEV;
> > + }
> > +
> > + 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 end;
> > +
> > + sprintf(name, "acpi_als%d", als_id++);
> > + als->classdev = als_device_register(&device->dev, name);
> > + if (IS_ERR(als->classdev)) {
> > + result = PTR_ERR(als->classdev);
> > + goto end;
> > + }
> > +
> > + result = device_create_file(als->classdev, &dev_attr_illuminance);
> > + if (result)
> > + als_device_unregister(als->classdev);
> > +
> > +end:
> > + if (result)
> If it fails, do you want to decrement als_id (for consistency sake if nothing else)?
sounds good.
refreshed patch attached.
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@...el.com>
---
Documentation/acpi/debug.txt | 1
MAINTAINERS | 7 +
drivers/acpi/Kconfig | 9 +
drivers/acpi/Makefile | 1
drivers/acpi/als.c | 226 +++++++++++++++++++++++++++++++++++++++++++
drivers/acpi/debug.c | 1
include/acpi/acpi_drivers.h | 1
7 files changed, 246 insertions(+)
Index: linux-2.6/drivers/acpi/als.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/acpi/als.c
@@ -0,0 +1,226 @@
+/*
+ * als.c - ACPI Ambient Light Sensor Driver
+ *
+ * Copyright (C) 2009 Intel Corp
+ * Copyright (C) 2009 Zhang Rui <rui.zhang@...el.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 PREFIX "ACPI: "
+
+#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 device *classdev; /* pointer to als sysfs/class device */
+ int illuminance;
+};
+
+/* --------------------------------------------------------------------------
+ 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"));
+ return -ENOENT;
+ }
+ als->illuminance = illuminance;
+ return 0;
+}
+
+
+/* --------------------------------------------------------------------------
+ sysfs I/F
+ -------------------------------------------------------------------------- */
+static int
+illuminance_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct acpi_device *device = to_acpi_device(dev->parent);
+ struct acpi_als *als = acpi_driver_data(device);
+ int result;
+
+ result = acpi_als_get_illuminance(als);
+ if (result)
+ return result;
+
+ if (als->illuminance < -1)
+ return -EINVAL;
+
+ return sprintf(buf, "%d\n", als->illuminance);
+}
+
+DEVICE_ATTR(illuminance, 0444, illuminance_show, NULL);
+
+/* --------------------------------------------------------------------------
+ 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:
+ /*
+ * TODO:
+ * re-evalute the color temperature and chromaticity
+ */
+ break;
+ case ACPI_ALS_NOTIFY_RESPONSE:
+ /*
+ * TODO:
+ * update the Ambient Light Illuminance to
+ * Display Luminance Adjustment Mappings
+ */
+ 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;
+ static int als_id;
+ char name[10];
+ struct acpi_als *als;
+
+ if (unlikely(als_id >= 10)) {
+ printk(KERN_WARNING PREFIX "Too many ALS devices found\n");
+ return -ENODEV;
+ }
+
+ 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 end;
+
+ sprintf(name, "acpi_als%d", als_id);
+ als->classdev = als_device_register(&device->dev, name);
+ if (IS_ERR(als->classdev)) {
+ result = PTR_ERR(als->classdev);
+ goto end;
+ }
+
+ result = device_create_file(als->classdev, &dev_attr_illuminance);
+ if (result)
+ als_device_unregister(als->classdev);
+
+end:
+ if (result)
+ kfree(als);
+ else
+ als_id++;
+
+ return result;
+}
+
+static int acpi_als_remove(struct acpi_device *device, int type)
+{
+ struct acpi_als *als = acpi_driver_data(device);
+
+ als_device_unregister(als->classdev);
+ 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);
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"
+ 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
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
Index: linux-2.6/MAINTAINERS
===================================================================
--- linux-2.6.orig/MAINTAINERS
+++ linux-2.6/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@...el.com>
+L: linux-acpi@...r.kernel.org
+W: http://www.lesswatts.org/projects/acpi/
+S: Supported
+F: drivers/acpi/als.c
+
ACPI BATTERY DRIVERS
M: Alexey Starikovskiy <astarikovskiy@...e.de>
L: linux-acpi@...r.kernel.org
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