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Date: Thu, 06 Aug 2009 09:09:21 -0600
From: Bjorn Helgaas <bjorn.helgaas@...com>
To: Zhang Rui <rui.zhang@...el.com>
Cc: linux-acpi <linux-acpi@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Pavel Machek <pavel@....cz>, Greg KH <greg@...ah.com>,
Richard Purdie <rpurdie@...ys.net>,
Matthew Wilcox <matthew@....cx>, Len Brown <lenb@...nel.org>,
"Valdis.Kletnieks@...edu" <Valdis.Kletnieks@...edu>
Subject: Re: [RFC PATCH V2 2/2] introduce ACPI ALS device driver
On Thu, 2009-08-06 at 16:31 +0800, Zhang Rui wrote:
> 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 driver.
>
> Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> ---
> Documentation/acpi/debug.txt | 1
> drivers/acpi/Kconfig | 9
> drivers/acpi/Makefile | 1
> drivers/acpi/als.c | 423 +++++++++++++++++++++++++++++++++++++++++++
> drivers/acpi/debug.c | 1
> include/acpi/acpi_drivers.h | 1
> 6 files changed, 436 insertions(+)
>
> Index: linux-2.6/drivers/acpi/als.c
> ===================================================================
> --- /dev/null
> +++ linux-2.6/drivers/acpi/als.c
> @@ -0,0 +1,423 @@
> +/*
> + * 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 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,
> + .ops = {
> + .add = acpi_als_add,
> + .resume = acpi_als_resume,
> + .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 */
> + if (als->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 the current ambient light illuminance
> + */
> +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 get_mapping_count(struct als_device *als_sys, int *count)
> +{
> + struct acpi_als *als = als_sys->devdata;
> + int result;
> +
> + result = acpi_als_get_mappings(als);
> + if (!result)
> + *count = als->count;
> +
> + return result;
> +}
> +
> +static int get_mapping_info(struct als_device *als_sys, int index,
> + int *illuminance, int *adjustment)
> +{
> + struct acpi_als *als = als_sys->devdata;
> + int result;
> +
> + if (index < 0 || index >= als->count)
> + return -EINVAL;
> +
> + result = acpi_als_get_mappings(als);
> + if (result)
> + return result;
> +
> + if (illuminance)
> + *illuminance = als->mappings[index].illuminance;
> + if (adjustment)
> + *adjustment = als->mappings[index].adjustment;
> +
> + return 0;
> +}
> +
> +struct als_device_ops acpi_als_ops = {
> + .get_illuminance = get_illuminance,
> + .get_mapping_count = get_mapping_count,
> + .get_mapping_info = get_mapping_info,
> +};
> +
> +/* --------------------------------------------------------------------------
> + Driver Model
> + -------------------------------------------------------------------------- */
> +
> +static void acpi_als_notify(struct acpi_device *device, u32 event)
> +{
> + struct acpi_als *als = acpi_driver_data(device);
> +
> + if (!als)
> + return;
You don't need this null pointer check. The notify handler is only
installed if the .add() method completes successfully, which means
the device->driver_data pointer has been set.
> +
> + 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);
> + als_device_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;
> + acpi_status status;
> + struct acpi_buffer name = { ACPI_ALLOCATE_BUFFER, NULL };
> +
> + 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;
> +
> + 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);
> +
> + status = acpi_get_name(als->device->handle, ACPI_FULL_PATHNAME, &name);
> + if (ACPI_FAILURE(status)) {
> + result = -ENODEV;
> + goto end;
> + }
> +
> + als->als_sys = als_device_register(&acpi_als_ops, name.pointer, als);
I don't think we should expose the ACPI pathname of the device here.
If we really need something in sysfs, I think some kind of link to the
underlying device would be better.
> + if (IS_ERR(als->als_sys)) {
> + result = -ENODEV;
> + if (als->mappings)
> + kfree(als->mappings);
> + }
> +
> + als_device_update_mappings(als->als_sys);
> +
> + kfree(name.pointer);
> +
> +end:
> + if (result)
> + kfree(als);
> + return result;
> +}
> +
> +static int acpi_als_resume(struct acpi_device *device)
> +{
> + struct acpi_als *als = acpi_driver_data(device);
> +
> + if (!als)
> + return -ENODEV;
This null pointer check isn't needed.
> +
> + 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 = acpi_driver_data(device);
> +
> + if (!als)
> + return -ENODEV;
Nor is this one.
> +
> + als_device_unregister(als->als_sys);
> + if (als->mappings)
> + 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);
> 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 modules will be called als.
"the module", not "the modules".
> +
> 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
>
>
--
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