From foo@baz Fri Aug 14 12:46:20 PDT 2009
Date: Fri, 14 Aug 2009 12:46:20 -0700
To: Greg KH <greg@kroah.com>
From: Greg Kroah-Hartman <gregkh@suse.de>
Subject: Samsung backlight driver
Patch-mainline: 2.6.32
References: bnc#527533, bnc#531297
This driver implements backlight controls for Samsung laptops that
currently do not have ACPI support for this control.
It has been tested on the N130 laptop and properly works there.
Info for the NC10 was provided by Soeren Sonnenburg <bugreports@nn7.de>
Info for the NP-Q45 from Jérémie Huchet <jeremie@lamah.info>
Many thanks to Dmitry Torokhov <dmitry.torokhov@gmail.com> for cleanups
and other suggestions on how to make the driver simpler.
Cc: Soeren Sonnenburg <bugreports@nn7.de>
Cc: Jérémie Huchet <jeremie@lamah.info>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/platform/x86/Kconfig | 12 ++
drivers/platform/x86/Makefile | 1
drivers/platform/x86/samsung-backlight.c | 178 +++++++++++++++++++++++++++++++
3 files changed, 191 insertions(+)
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -425,4 +425,16 @@ config ACPI_TOSHIBA
If you have a legacy free Toshiba laptop (such as the Libretto L1
series), say Y.
+
+config SAMSUNG_BACKLIGHT
+ tristate "Samsung Backlight driver"
+ depends on BACKLIGHT_CLASS_DEVICE
+ depends on DMI
+ ---help---
+ This driver adds support to control the backlight on a number of
+ Samsung laptops, like the N130.
+
+ It will only be loaded on laptops that properly need it, so it is
+ safe to say Y here.
+
endif # X86_PLATFORM_DEVICES
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -20,3 +20,4 @@ obj-$(CONFIG_INTEL_MENLOW) += intel_menl
obj-$(CONFIG_ACPI_WMI) += wmi.o
obj-$(CONFIG_ACPI_ASUS) += asus_acpi.o
obj-$(CONFIG_ACPI_TOSHIBA) += toshiba_acpi.o
+obj-$(CONFIG_SAMSUNG_BACKLIGHT) += samsung-backlight.o
--- /dev/null
+++ b/drivers/platform/x86/samsung-backlight.c
@@ -0,0 +1,178 @@
+/*
+ * Samsung N130 and NC10 Laptop Backlight driver
+ *
+ * Copyright (C) 2009 Greg Kroah-Hartman (gregkh@suse.de)
+ * Copyright (C) 2009 Novell Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/backlight.h>
+#include <linux/fb.h>
+#include <linux/dmi.h>
+
+#define MAX_BRIGHT 0x07
+#define OFFSET 0xf4
+
+/*
+ * HAL/gnome-display-manager really wants us to only set 8 different levels for
+ * the brightness control. And since 256 different levels seems a bit
+ * overkill, that's fine. So let's map the 256 values to 8 different ones:
+ *
+ * userspace 0 1 2 3 4 5 6 7
+ * hardware 0 36 72 108 144 180 216 252
+ *
+ * or hardware = (userspace * 36) - 1 iff userspace != 0
+ */
+
+
+static int offset = OFFSET;
+module_param(offset, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(offset, "The offset into the PCI device for the brightness control");
+
+static struct pci_dev *pci_device;
+static struct backlight_device *backlight_device;
+
+static u8 read_brightness(void)
+{
+ u8 kernel_brightness;
+ u8 user_brightness = 0;
+
+ pci_read_config_byte(pci_device, offset, &kernel_brightness);
+ if (kernel_brightness != 0)
+ user_brightness = kernel_brightness / 36;
+
+ return user_brightness;
+}
+
+static void set_brightness(u8 user_brightness)
+{
+ u16 kernel_brightness = 0;
+
+ if (user_brightness != 0)
+ kernel_brightness = (user_brightness * 36) - 1;
+ pci_write_config_byte(pci_device, offset, (u8)kernel_brightness);
+}
+
+static int get_brightness(struct backlight_device *bd)
+{
+ return bd->props.brightness;
+}
+
+static int update_status(struct backlight_device *bd)
+{
+ set_brightness(bd->props.brightness);
+ return 0;
+}
+
+static struct backlight_ops backlight_ops = {
+ .get_brightness = get_brightness,
+ .update_status = update_status,
+};
+
+static int __init dmi_check_cb(const struct dmi_system_id *id)
+{
+ printk(KERN_INFO KBUILD_MODNAME ": found laptop model '%s'\n",
+ id->ident);
+ return 0;
+}
+
+static struct dmi_system_id __initdata samsung_dmi_table[] = {
+ {
+ .ident = "N120",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "N120"),
+ DMI_MATCH(DMI_BOARD_NAME, "N120"),
+ },
+ .callback = dmi_check_cb,
+ },
+ {
+ .ident = "N130",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "N130"),
+ DMI_MATCH(DMI_BOARD_NAME, "N130"),
+ },
+ .callback = dmi_check_cb,
+ },
+ {
+ .ident = "NC10",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "NC10"),
+ DMI_MATCH(DMI_BOARD_NAME, "NC10"),
+ },
+ .callback = dmi_check_cb,
+ },
+ {
+ .ident = "NP-Q45",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "SQ45S70S"),
+ DMI_MATCH(DMI_BOARD_NAME, "SQ45S70S"),
+ },
+ .callback = dmi_check_cb,
+ },
+ { },
+};
+
+static int __init samsung_init(void)
+{
+ if (!dmi_check_system(samsung_dmi_table))
+ return -ENODEV;
+
+ /*
+ * The Samsung N120, N130, and NC10 use pci device id 0x27ae, while the
+ * NP-Q45 uses 0x2a02. Odds are we might need to add more to the
+ * list over time...
+ */
+ pci_device = pci_get_device(PCI_VENDOR_ID_INTEL, 0x27ae, NULL);
+ if (!pci_device) {
+ pci_device = pci_get_device(PCI_VENDOR_ID_INTEL, 0x2a02, NULL);
+ if (!pci_device)
+ return -ENODEV;
+ }
+
+ /* create a backlight device to talk to this one */
+ backlight_device = backlight_device_register("samsung",
+ &pci_device->dev,
+ NULL, &backlight_ops);
+ if (IS_ERR(backlight_device)) {
+ pci_dev_put(pci_device);
+ return PTR_ERR(backlight_device);
+ }
+
+ backlight_device->props.max_brightness = MAX_BRIGHT;
+ backlight_device->props.brightness = read_brightness();
+ backlight_device->props.power = FB_BLANK_UNBLANK;
+ backlight_update_status(backlight_device);
+
+ return 0;
+}
+
+static void __exit samsung_exit(void)
+{
+ backlight_device_unregister(backlight_device);
+
+ /* we are done with the PCI device, put it back */
+ pci_dev_put(pci_device);
+}
+
+module_init(samsung_init);
+module_exit(samsung_exit);
+
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@suse.de>");
+MODULE_DESCRIPTION("Samsung Backlight driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnN120:*:rnN120:*");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnN130:*:rnN130:*");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnNC10:*:rnNC10:*");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnSQ45S70S:*:rnSQ45S70S:*");