Platform: Samsung Q10 backlight driver

This adds backlight control on the Samsung Q10 laptop, which does not support
the SABI interface. Also tested successfully on the Dell Latitude X200.

Signed-off-by: Frederick van der Wyck <fvanderwyck@gmail.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

3 files changed, 205 insertions, 0 deletions

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 45e0191c35dd..1e88d4785321 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -769,4 +769,12 @@ config INTEL_OAKTRAIL
           enable/disable the Camera, WiFi, BT etc. devices. If in doubt, say Y
           here; it will only load on supported platforms.
 
+config SAMSUNG_Q10
+        tristate "Samsung Q10 Extras"
+        depends on SERIO_I8042
+        select BACKLIGHT_CLASS_DEVICE
+        ---help---
+          This driver provides support for backlight control on Samsung Q10
+          and related laptops, including Dell Latitude X200.
+
 endif # X86_PLATFORM_DEVICES
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index afc1f832aa67..293a320d9faa 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -44,3 +44,4 @@ obj-$(CONFIG_SAMSUNG_LAPTOP)	+= samsung-laptop.o
 obj-$(CONFIG_MXM_WMI)           += mxm-wmi.o
 obj-$(CONFIG_INTEL_MID_POWER_BUTTON)    += intel_mid_powerbtn.o
 obj-$(CONFIG_INTEL_OAKTRAIL)    += intel_oaktrail.o
+obj-$(CONFIG_SAMSUNG_Q10)       += samsung-q10.o
diff --git a/drivers/platform/x86/samsung-q10.c b/drivers/platform/x86/samsung-q10.c
new file mode 100644
index 000000000000..54cf3d63fe8d
--- /dev/null
+++ b/drivers/platform/x86/samsung-q10.c
@@ -0,0 +1,196 @@
+/*
+ *  Driver for Samsung Q10 and related laptops: controls the backlight
+ *
+ *  Copyright (c) 2011 Frederick van der Wyck <fvanderwyck@gmail.com>
+ *
+ *  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/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/backlight.h>
+#include <linux/i8042.h>
+#include <linux/dmi.h>
+
+#define SAMSUNGQ10_BL_MAX_INTENSITY      255
+#define SAMSUNGQ10_BL_DEFAULT_INTENSITY  185
+
+#define SAMSUNGQ10_BL_8042_CMD           0xbe
+#define SAMSUNGQ10_BL_8042_DATA          { 0x89, 0x91 }
+
+static int samsungq10_bl_brightness;
+
+static bool force;
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force,
+                "Disable the DMI check and force the driver to be loaded");
+
+static int samsungq10_bl_set_intensity(struct backlight_device *bd)
+{
+
+        int brightness = bd->props.brightness;
+        unsigned char c[3] = SAMSUNGQ10_BL_8042_DATA;
+
+        c[2] = (unsigned char)brightness;
+        i8042_lock_chip();
+        i8042_command(c, (0x30 << 8) | SAMSUNGQ10_BL_8042_CMD);
+        i8042_unlock_chip();
+        samsungq10_bl_brightness = brightness;
+
+        return 0;
+}
+
+static int samsungq10_bl_get_intensity(struct backlight_device *bd)
+{
+        return samsungq10_bl_brightness;
+}
+
+static const struct backlight_ops samsungq10_bl_ops = {
+        .get_brightness = samsungq10_bl_get_intensity,
+        .update_status  = samsungq10_bl_set_intensity,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int samsungq10_suspend(struct device *dev)
+{
+        return 0;
+}
+
+static int samsungq10_resume(struct device *dev)
+{
+
+        struct backlight_device *bd = dev_get_drvdata(dev);
+
+        samsungq10_bl_set_intensity(bd);
+        return 0;
+}
+#else
+#define samsungq10_suspend NULL
+#define samsungq10_resume  NULL
+#endif
+
+static SIMPLE_DEV_PM_OPS(samsungq10_pm_ops,
+                          samsungq10_suspend, samsungq10_resume);
+
+static int __devinit samsungq10_probe(struct platform_device *pdev)
+{
+
+        struct backlight_properties props;
+        struct backlight_device *bd;
+
+        memset(&props, 0, sizeof(struct backlight_properties));
+        props.type = BACKLIGHT_PLATFORM;
+        props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
+        bd = backlight_device_register("samsung", &pdev->dev, NULL,
+                                       &samsungq10_bl_ops, &props);
+        if (IS_ERR(bd))
+                return PTR_ERR(bd);
+
+        platform_set_drvdata(pdev, bd);
+
+        bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
+        samsungq10_bl_set_intensity(bd);
+
+        return 0;
+}
+
+static int __devexit samsungq10_remove(struct platform_device *pdev)
+{
+
+        struct backlight_device *bd = platform_get_drvdata(pdev);
+
+        bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
+        samsungq10_bl_set_intensity(bd);
+
+        backlight_device_unregister(bd);
+
+        return 0;
+}
+
+static struct platform_driver samsungq10_driver = {
+        .driver         = {
+                .name   = KBUILD_MODNAME,
+                .owner  = THIS_MODULE,
+                .pm     = &samsungq10_pm_ops,
+        },
+        .probe          = samsungq10_probe,
+        .remove         = __devexit_p(samsungq10_remove),
+};
+
+static struct platform_device *samsungq10_device;
+
+static int __init dmi_check_callback(const struct dmi_system_id *id)
+{
+        printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
+        return 0;
+}
+
+static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
+        {
+                .ident = "Samsung Q10",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
+                },
+                .callback = dmi_check_callback,
+        },
+        {
+                .ident = "Samsung Q20",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
+                },
+                .callback = dmi_check_callback,
+        },
+        {
+                .ident = "Samsung Q25",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
+                },
+                .callback = dmi_check_callback,
+        },
+        {
+                .ident = "Dell Latitude X200",
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
+                },
+                .callback = dmi_check_callback,
+        },
+        { },
+};
+MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
+
+static int __init samsungq10_init(void)
+{
+        if (!force && !dmi_check_system(samsungq10_dmi_table))
+                return -ENODEV;
+
+        samsungq10_device = platform_create_bundle(&samsungq10_driver,
+                                                   samsungq10_probe,
+                                                   NULL, 0, NULL, 0);
+
+        if (IS_ERR(samsungq10_device))
+                return PTR_ERR(samsungq10_device);
+
+        return 0;
+}
+
+static void __exit samsungq10_exit(void)
+{
+        platform_device_unregister(samsungq10_device);
+        platform_driver_unregister(&samsungq10_driver);
+}
+
+module_init(samsungq10_init);
+module_exit(samsungq10_exit);
+
+MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
+MODULE_DESCRIPTION("Samsung Q10 Driver");
+MODULE_LICENSE("GPL");