[Intel-gfx] Legacy backlight control with KMS and BACKLIGHT property
Greg KH
greg at kroah.com
Mon Aug 17 00:08:27 CEST 2009
On Sat, Aug 15, 2009 at 01:33:13PM +0100, Mike Lothian wrote:
> 2009/8/15 Jesse Barnes <jbarnes at virtuousgeek.org>:
> > On Fri, 14 Aug 2009 12:28:47 -0700
> > Greg KH <greg at kroah.com> wrote:
> >
> >> On Fri, Aug 14, 2009 at 12:08:21PM -0700, Greg KH wrote:
> >> > Here's a first cut at such a driver. It works for me on this
> >> > laptop, but note that it will try to work on _any_ Intel-based
> >> > system. I'll figure out how to do this only for specific machines
> >> > based on DMI data next.
> >>
> >> And here's one that is set for DMI data to only load on the proper
> >> ones.
> >>
> >> I'll push this upstream now, if there are no objections.
> >
> > Yeah, looks fairly reasonable. This code should work on most pre-965
> > chipsets too, since they share the LBB regs. There are a couple of
> > other things to take into consideration: I think the VBIOS indicates
> > whether the controls are inverted (i.e. a value of 0xff is minimum
> > brightness) and there may also be some stepping info.
> >
> > So ultimately I'd like to see this be part of the i915 driver as one of
> > a few different methods supported (hopefully we can autodetect them
> > better than the 2D driver though, using the VBIOS and DMI in the
> > kernel).
> >
> > The other three methods that need to export sysfs interfaces are
> > OpRegion (already done), i2c (some machines have external controllers;
> > the VBIOS describes how to interact with them) and PWM (the "native"
> > power modulation regs).
>
> This is great news guys, hopefully I'll finally be able to control the
> screen brightness of my GM45 in my Samsung R510
>
> If you want a guinea pig to test your code please feel free to forward patches
A driver for other Samsung devices is below. If you think your laptop
also works this way (by changing the brightness value by reading and
writing the 0xf4 pci config value directly), then we can add support for
your laptop to this driver as well, just send me the output of:
lspci
lspci -n
grep . /sys/class/dmi/id/*
thanks,
greg k-h
-----------
From: Greg Kroah-Hartman <gregkh at suse.de>
Subject: Samsung backlight driver
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 at nn7.de>
Info for the NP-Q45 from Jérémie Huchet <jeremie at lamah.info>
Many thanks to Dmitry Torokhov <dmitry.torokhov at gmail.com> for cleanups
and other suggestions on how to make the driver simpler.
Cc: Soeren Sonnenburg <bugreports at nn7.de>
Cc: Jérémie Huchet <jeremie at lamah.info>
Cc: Dmitry Torokhov <dmitry.torokhov at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
---
drivers/platform/x86/Kconfig | 12 ++
drivers/platform/x86/Makefile | 1
drivers/platform/x86/samsung-backlight.c | 157 +++++++++++++++++++++++++++++++
3 files changed, 170 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 +1,157 @@
+/*
+ * Samsung N130 and NC10 Laptop Backlight driver
+ *
+ * Copyright (C) 2009 Greg Kroah-Hartman (gregkh at 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 0xff
+#define OFFSET 0xf4
+
+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 brightness;
+
+ pci_read_config_byte(pci_device, offset, &brightness);
+ return brightness;
+}
+
+static void set_brightness(u8 brightness)
+{
+ pci_write_config_byte(pci_device, offset, 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 at 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:*");
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