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@xxxxxxxxx>
> ---
> 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@xxxxxxxxx>
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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