PATCH [1/3]: Provide generic backlight support in Asus ACPI driver

Matthew Garrett
2006-04-19T18:49:27Z

Here are some fixed-up versions of my patches to move acpi drivers
towards using the standard backlight interface. I've kept the dynamic
allocation of backlight_device for now, since changing that would also
mean changing the backlight core code and updating other drivers.

Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org>

diff -ur drivers/acpi.bak/asus_acpi.c drivers/acpi/asus_acpi.c
--- drivers/acpi.bak/asus_acpi.c 2006-04-03 04:22:10 +0100
+++ a/drivers/acpi/asus_acpi.c 2006-04-19 19:29:50 +0100
@@ -38,6 +38,8 @@
#include <linux/init.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
#include <acpi/acpi_drivers.h>
#include <acpi/acpi_bus.h>
#include <asm/uaccess.h>
@@ -82,6 +84,8 @@
module_param(asus_gid, uint, 0);
MODULE_PARM_DESC(asus_gid, "GID for entries in /proc/acpi/asus.\n");

+static struct backlight_device *asus_backlight_device;
+
/* For each model, all features implemented,
* those marked with R are relative to HOTK, A for absolute */
struct model_data {
@@ -689,7 +693,7 @@
return count;
}

-static int read_brightness(void)
+static int read_brightness(struct backlight_device *bd)
{
int value;

@@ -711,39 +715,50 @@
/*
* Change the brightness level
*/
-static void set_brightness(int value)
+static int set_brightness(unsigned int value)
{
acpi_status status = 0;

+ if (value > 15)
+ value = 15;
+
/* SPLV laptop */
if (hotk->methods->brightness_set) {
if (!write_acpi_int(hotk->handle, hotk->methods->brightness_set,
value, NULL))
printk(KERN_WARNING
"Asus ACPI: Error changing brightness\n");
- return;
+ return -EINVAL;
}

/* No SPLV method if we are here, act as appropriate */
- value -= read_brightness();
+ value -= read_brightness(NULL);
while (value != 0) {
status = acpi_evaluate_object(NULL, (value > 0) ?
hotk->methods->brightness_up :
hotk->methods->brightness_down,
NULL, NULL);
(value > 0) ? value-- : value++;
- if (ACPI_FAILURE(status))
+ if (ACPI_FAILURE(status)) {
printk(KERN_WARNING
"Asus ACPI: Error changing brightness\n");
+ return -EINVAL;
+ }
}
- return;
+ return 0;
+}
+
+static int update_brightness(struct backlight_device *bd)
+{
+ int value = bd->props->brightness;
+ return set_brightness (value);
}

static int
proc_read_brn(char *page, char **start, off_t off, int count, int *eof,
void *data)
{
- return sprintf(page, "%d\n", read_brightness());
+ return sprintf(page, "%d\n", read_brightness(NULL));
}

static int
@@ -754,9 +769,7 @@

count = parse_arg(buffer, count, &value);
if (count > 0) {
- value = (0 < value) ? ((15 < value) ? 15 : value) : 0;
- /* 0 <= value <= 15 */
- set_brightness(value);
+ set_brightness(value);
} else if (count < 0) {
printk(KERN_WARNING "Asus ACPI: Error reading user input\n");
}
@@ -1207,6 +1220,13 @@
return 0;
}

+static struct backlight_properties asusbl_data = {
+ .owner = THIS_MODULE,
+ .get_brightness = read_brightness,
+ .update_status = update_brightness,
+ .max_brightness = 15,
+};
+
static int __init asus_acpi_init(void)
{
int result;
@@ -1232,15 +1252,26 @@
return -ENODEV;
}

+ asus_backlight_device = backlight_device_register("asus_bl", NULL,
+ &asusbl_data);
+
+ if (IS_ERR (asus_backlight_device)) {
+ printk("Unable to register ASUS backlight\n");
+ asus_backlight_device = NULL;
+ }
+
return 0;
}

static void __exit asus_acpi_exit(void)
{
- acpi_bus_unregister_driver(&asus_hotk_driver);
- remove_proc_entry(PROC_ASUS, acpi_root_dir);
+ if (asus_backlight_device)
+ backlight_device_unregister(asus_backlight_device);
+
+ acpi_bus_unregister_driver (&asus_hotk_driver);
+ remove_proc_entry (PROC_ASUS, acpi_root_dir);

- acpi_os_free(asus_info);
+ acpi_os_free (asus_info);

return;
}
diff -ur drivers/acpi.bak/Kconfig drivers/acpi/Kconfig
--- drivers/acpi.bak/Kconfig 2006-04-18 08:51:49 +0100
+++ a/drivers/acpi/Kconfig 2006-04-19 19:27:08 +0100
@@ -168,6 +168,7 @@
config ACPI_ASUS
tristate "ASUS/Medion Laptop Extras"
depends on X86
+ select BACKLIGHT_DEVICE
---help---
This driver provides support for extra features of ACPI-compatible
ASUS laptops. As some of Medion laptops are made by ASUS, it may also