Message-ID: <20090821225925.GA27625@kroah.com>
Date:	Fri, 21 Aug 2009 15:59:25 -0700
From:	Greg KH <greg@...ah.com>
To:	linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Soeren Sonnenburg <bugreports@....de>,
	Jérémie Huchet <jeremie@...ah.info>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: [PATCH] Samsung laptop driver

Well, it turns out that for the Samsung laptops, we aren't supposed to
be poking into the raw PCI config space to control the backlight,
there's a SMI way to do it instead (Matthew, you were right.)

So here's an updated version of the driver, with lots of debugging still
left in it, that controls the backlight on a N130 through the "proper"
way.

It's bigger than the last driver, as I've added lots of documenation
about this new interface.  I'm also working on adding wireless LED
support, as well as maybe CPU temperature monitoring to the driver, as
that can be controlled through this interface.

Soeren and Jérémie, I took out support for both of your laptops, as I
didn't know if it supported this type of interface.  Could you load the
driver with the "force=1" parameter:
	modprobe samsung-laptop force=1
and tell me what the kernel log shows for your laptop?  If it works,
I'll add the DMI values back to the driver.

Jesse, I don't know how this is going to play with your recently added
backlight support for the i915 driver.  As you don't have control over
the LEDs and other stuff that this driver is going to support, I think
we need some way to keep the i915 driver from messing with the backlight
values, don't you think?

thanks,

greg k-h

--------------


From: Greg Kroah-Hartman <gregkh@...e.de>
Subject: Samsung laptop 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.

Many thanks to Dmitry Torokhov <dmitry.torokhov@...il.com> for cleanups
and other suggestions on how to make the driver simpler.

Cc: Soeren Sonnenburg <bugreports@....de>
Cc: Jérémie Huchet <jeremie@...ah.info>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 drivers/platform/x86/Kconfig          |   12 
 drivers/platform/x86/Makefile         |    1 
 drivers/platform/x86/samsung-laptop.c |  420 ++++++++++++++++++++++++++++++++++
 3 files changed, 433 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_LAPTOP
+	tristate "Samsung Laptop 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, and control for some of the LEDs
+
+	  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_LAPTOP)	+= samsung-laptop.o
--- /dev/null
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -0,0 +1,420 @@
+/*
+ * Samsung N130 and NC120 Laptop driver
+ *
+ * Copyright (C) 2009 Greg Kroah-Hartman (gregkh@...e.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>
+#include <linux/platform_device.h>
+
+/*
+ * This driver is needed because a number of Samsung laptops do not hook
+ * their control settings through ACPI.  So we have to poke around in the
+ * BIOS to do things like brightness values, and "special" key controls.
+ */
+
+
+/*
+ * We have 0 - 8 as valid brightness levels.  The specs say that level 0 should
+ * be reserved by the BIOS (which really doesn't make much sense), we tell
+ * userspace that the value is 0 - 7 and then just tell the hardware 1 - 8
+ */
+#define MAX_BRIGHT	0x07
+
+/* get model returns 4 characters that describe the model of the laptop */
+#define SABI_GET_MODEL			0x04
+
+/* Brightness is 0 - 8, as described above.  Value 0 is for the BIOS to use */
+#define SABI_GET_BRIGHTNESS		0x10
+#define SABI_SET_BRIGHTNESS		0x11
+
+/* 0 is off, 1 is on, and 2 is a second user-defined key? */
+#define SABI_GET_WIRELESS_BUTTON	0x12
+#define SABI_SET_WIRELESS_BUTTON	0x13
+
+/* Temperature is returned in degress Celsius from what I can guess. */
+#define SABI_GET_CPU_TEMP		0x29
+
+/* 0 is off, 1 is on.  Doesn't seem to work on a N130 for some reason */
+#define SABI_GET_BACKLIGHT		0x2d
+#define SABI_SET_BACKLIGHT		0x2e
+
+/*
+ * This is different
+ * There is 3 different modes here:
+ *   0 - off
+ *   1 - on
+ *   2 - max performance mode
+ * off is "normal" mode.
+ * on means that whatever the bios setting for etiquette mode, is enabled.  It
+ * seems that the BIOS can set either "auto" mode, or "slow" mode.  If "slow"
+ * mode is set, the fan turns off, and the cpu is throttled down to not cause
+ * the fan to turn on if at all possible.
+ * max performance means that the processor can be overclocked and run faster
+ * then is physically possible.  Ok, maybe not physically possible, but it is
+ * overclocked.  Funny that the system has a setting for this...
+ */
+#define SABI_GET_ETIQUETTE_MODE		0x31
+#define SABI_SET_ETIQUETTE_MODE		0x32
+
+/*
+ * I imagine that on some laptops there is a bluetooth switch, but I don't know
+ * what that looks like, or where it is in the BIOS address space
+ */
+
+
+/*
+ * SABI HEADER in low memory (f0000)
+ * We need to poke through memory to find a signature in order to find the
+ * exact location of this structure.
+ */
+struct sabi_header {
+	u16 portNo;
+	u8 ifaceFunc;
+	u8 enMem;
+	u8 reMem;
+	u16 dataOffset;
+	u16 dataSegment;
+	u8 BIOSifver;
+	u8 LauncherString;
+} __attribute__((packed));
+
+/*
+ * The SABI interface that we use to write and read values from the system.
+ * It is found by looking at the dataOffset and dataSegment values in the sabi
+ * header structure
+ */
+struct sabi_interface {
+	u16 mainfunc;
+	u16 subfunc;
+	u8 complete;
+	u8 retval[20];
+} __attribute__((packed));
+
+/* Structure to get data back to the calling function */
+struct sabi_retval {
+	u8 retval[20];
+};
+
+static struct sabi_header __iomem *sabi;
+static struct sabi_interface __iomem *sabi_iface;
+static void __iomem *f0000_segment;
+static struct backlight_device *backlight_device;
+static struct mutex sabi_mutex;
+static struct platform_device *sdev;
+
+static int force;
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force, "Disable the DMI check and forces the driver to be loaded");
+
+static int debug;
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");
+
+static int sabi_get_command(u8 command, struct sabi_retval *sretval)
+{
+	int retval = 0;
+
+	mutex_lock(&sabi_mutex);
+
+	/* enable memory to be able to write to it */
+	outb(readb(&sabi->enMem), readw(&sabi->portNo));
+
+	/* write out the command */
+	writew(0x5843, &sabi_iface->mainfunc);
+	writew(command, &sabi_iface->subfunc);
+	writeb(0, &sabi_iface->complete);
+	outb(readb(&sabi->ifaceFunc), readw(&sabi->portNo));
+
+	/* sleep for a bit to let the command complete */
+	msleep(100);
+
+	/* write protect memory to make it safe */
+	outb(readb(&sabi->reMem), readw(&sabi->portNo));
+
+	/* see if the command actually succeeded */
+	if (readb(&sabi_iface->complete) == 0xaa &&
+	    readb(&sabi_iface->retval[0]) != 0xff) {
+		/*
+		 * It did!
+		 * Save off the data into a structure so the caller use it.
+		 * Right now we only care about the first 4 bytes,
+		 * I suppose there are commands that need more, but I don't
+		 * know about them.
+		 */
+		sretval->retval[0] = readb(&sabi_iface->retval[0]);
+		sretval->retval[1] = readb(&sabi_iface->retval[1]);
+		sretval->retval[2] = readb(&sabi_iface->retval[2]);
+		sretval->retval[3] = readb(&sabi_iface->retval[3]);
+		goto exit;
+	}
+
+	/* Something bad happened, so report it and error out */
+	printk(KERN_WARNING "SABI command 0x%02x failed with completion flag 0x%02x and output 0x%02x\n",
+		command, readb(&sabi_iface->complete),
+		readb(&sabi_iface->retval[0]));
+	retval = -EINVAL;
+exit:
+	mutex_unlock(&sabi_mutex);
+	return retval;
+
+}
+
+static int sabi_set_command(u8 command, u8 data)
+{
+	int retval = 0;
+
+	mutex_lock(&sabi_mutex);
+
+	/* enable memory to be able to write to it */
+	outb(readb(&sabi->enMem), readw(&sabi->portNo));
+
+	/* write out the command */
+	writew(0x5843, &sabi_iface->mainfunc);
+	writew(command, &sabi_iface->subfunc);
+	writeb(0, &sabi_iface->complete);
+	writeb(data, &sabi_iface->retval[0]);
+	outb(readb(&sabi->ifaceFunc), readw(&sabi->portNo));
+
+	/* sleep for a bit to let the command complete */
+	msleep(100);
+
+	/* write protect memory to make it safe */
+	outb(readb(&sabi->reMem), readw(&sabi->portNo));
+
+	/* see if the command actually succeeded */
+	if (readb(&sabi_iface->complete) == 0xaa &&
+	    readb(&sabi_iface->retval[0]) != 0xff) {
+		/* it did! */
+		goto exit;
+	}
+
+	/* Something bad happened, so report it and error out */
+	printk(KERN_WARNING "SABI command 0x%02x failed with completion flag 0x%02x and output 0x%02x\n",
+		command, readb(&sabi_iface->complete),
+		readb(&sabi_iface->retval[0]));
+	retval = -EINVAL;
+exit:
+	mutex_unlock(&sabi_mutex);
+	return retval;
+}
+
+static u8 read_brightness(void)
+{
+	struct sabi_retval sretval;
+	int user_brightness = 0;
+	int retval;
+
+	retval = sabi_get_command(SABI_GET_BACKLIGHT, &sretval);
+	if (!retval)
+		user_brightness = sretval.retval[0];
+		if (user_brightness != 0)
+			--user_brightness;
+	return user_brightness;
+}
+
+static void set_brightness(u8 user_brightness)
+{
+	sabi_set_command(SABI_SET_BRIGHTNESS, user_brightness + 1);
+}
+
+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,
+	},
+	{ },
+};
+
+
+static int __init samsung_init(void)
+{
+	struct sabi_retval sretval;
+	const char *testStr = "SwSmi@";
+	void __iomem *memcheck;
+	unsigned int ifaceP;
+	int pStr;
+	int loca;
+	int retval;
+
+	mutex_init(&sabi_mutex);
+
+	if (!force && !dmi_check_system(samsung_dmi_table))
+		return -ENODEV;
+
+	f0000_segment = ioremap(0xf0000, 0xffff);
+	if (!f0000_segment) {
+		printk(KERN_ERR "Can't map the segment at 0xf0000\n");
+		return -EINVAL;
+	}
+
+	/* Try to find the signature "SwSmi@" in memory to find the header */
+	pStr = 0;
+	memcheck = f0000_segment;
+	for (loca = 0; loca < 0xffff; loca++) {
+		char temp = readb(memcheck + loca);
+
+		if (temp == testStr[pStr]) {
+			if (pStr == 5)
+				break;
+			++pStr;
+		} else {
+			pStr = 0;
+		}
+	}
+	if (loca == 0xffff) {
+		printk(KERN_INFO "This computer does not support SABI\n");
+		goto error_no_signature;
+		}
+
+	/* point to the SMI port Number */
+	loca += 1;
+	sabi = (struct sabi_header __iomem *)(loca + memcheck);
+	if (!sabi) {
+		printk(KERN_ERR "Can't remap %p\n", loca + memcheck);
+		goto exit;
+	}
+
+	printk(KERN_INFO "This computer supports SABI==%x\n", loca + 0xf0000 - 6);
+	printk(KERN_INFO "SABI header:\n");
+	printk(KERN_INFO " SMI Port Number = 0x%04x\n", readw(&sabi->portNo));
+	printk(KERN_INFO " SMI Interface Function = 0x%02x\n", readb(&sabi->ifaceFunc));
+	printk(KERN_INFO " SMI enable memory buffer = 0x%02x\n", readb(&sabi->enMem));
+	printk(KERN_INFO " SMI restore memory buffer = 0x%02x\n", readb(&sabi->reMem));
+	printk(KERN_INFO " SABI data offset = 0x%04x\n", readw(&sabi->dataOffset));
+	printk(KERN_INFO " SABI data segment = 0x%04x\n", readw(&sabi->dataSegment));
+	printk(KERN_INFO " BIOS interface version = 0x%02x\n", readb(&sabi->BIOSifver));
+	printk(KERN_INFO " KBD Launcher string = 0x%02x\n", readb(&sabi->LauncherString));
+
+	/* Get a pointer to the SABI Interface */
+	ifaceP = (readw(&sabi->dataSegment) & 0x0ffff) << 4;
+	ifaceP += readw(&sabi->dataOffset) & 0x0ffff;
+	sabi_iface = (struct sabi_interface __iomem *)ioremap(ifaceP, 16);
+	if (!sabi_iface) {
+		printk(KERN_ERR "Can't remap %x\n", ifaceP);
+		goto exit;
+	}
+	printk(KERN_INFO "SABI Interface = %p\n", sabi_iface);
+
+	retval = sabi_get_command(SABI_GET_MODEL, &sretval);
+	if (!retval) {
+		printk(KERN_INFO "Model Name %c%c%c%c\n",
+			sretval.retval[0],
+			sretval.retval[1],
+			sretval.retval[2],
+			sretval.retval[3]);
+	}
+
+	retval = sabi_get_command(SABI_GET_BACKLIGHT, &sretval);
+	if (!retval)
+		printk("backlight = 0x%02x\n", sretval.retval[0]);
+
+	retval = sabi_get_command(SABI_GET_WIRELESS_BUTTON, &sretval);
+	if (!retval)
+		printk("wireless button = 0x%02x\n", sretval.retval[0]);
+
+	retval = sabi_get_command(SABI_GET_BRIGHTNESS, &sretval);
+	if (!retval)
+		printk("brightness = 0x%02x\n", sretval.retval[0]);
+
+	retval = sabi_get_command(SABI_GET_ETIQUETTE_MODE, &sretval);
+	if (!retval)
+		printk("etiquette mode = 0x%02x\n", sretval.retval[0]);
+	retval = sabi_get_command(SABI_GET_CPU_TEMP, &sretval);
+	if (!retval)
+		printk("cpu temp = 0x%02x\n", sretval.retval[0]);
+
+	/* knock up a platform device to hang stuff off of */
+	sdev = platform_device_register_simple("samsung", -1, NULL, 0);
+	if (IS_ERR(sdev))
+		goto error_no_platform;
+
+	/* create a backlight device to talk to this one */
+	backlight_device = backlight_device_register("samsung", &sdev->dev,
+						     NULL, &backlight_ops);
+	if (IS_ERR(backlight_device))
+		goto error_no_backlight;
+
+	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);
+
+exit:
+	return 0;
+
+error_no_backlight:
+	platform_device_unregister(sdev);
+
+error_no_platform:
+	iounmap(sabi_iface);
+
+error_no_signature:
+	iounmap(f0000_segment);
+	return -EINVAL;
+}
+
+static void __exit samsung_exit(void)
+{
+	backlight_device_unregister(backlight_device);
+	iounmap(sabi_iface);
+	iounmap(f0000_segment);
+	platform_device_unregister(sdev);
+}
+
+module_init(samsung_init);
+module_exit(samsung_exit);
+
+MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@...e.de>");
+MODULE_DESCRIPTION("Samsung Backlight driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnN120:*:rnN120:*");
+MODULE_ALIAS("dmi:*:svnSAMSUNGELECTRONICSCO.,LTD.:pnN130:*:rnN130:*");
--
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