[PATCH] platform: add support for samsung nc210/nc110

[Jason Stubbs <jasonbstubbs@gmail.com>]

From: Jason Stubbs <jasonbstubbs@gmail.com>

Note, I don't expect this patch to go in and would actually just like some
feedback on how to better handle the set_brightness problem. Note also that
this patch won't apply on top of my brightness min/max fixes patch and I'll
redo this one as necessary.

This patch adds support for the NC210/NC110 to the samsung-laptop driver.

All SABI commands except for set_brightness work as expected. The behaviour
of set_brightness is as follows:

- Setting a new brightness will only step one level toward the new brightness
  level. For example, setting a level of 5 when the current level is 2 will
  result in a brightness level of 3.
- A spurious KEY_BRIGHTNESS_UP or KEY_BRIGHTNESS_DOWN event is also generated
  along with the change in brightness.
- Neither of the above two issues occur when changing from/to brightness level 0.

The changes in set_brightness() work around the above while attempting to
minimize flicker due to jumping to and from brightness level 0.

Signed-off-by: Jason Stubbs <jasonbstubbs@gmail.com>
---
diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index d347116..01d5278 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -380,6 +380,14 @@ static void set_brightness(u8 user_brightness)
 {
 	u8 user_level = user_brightness - sabi_config->min_brightness;
 
+	if (user_level == read_brightness()) {
+		return;
+	}
+
+	if (sabi_config->min_brightness == 0 && user_level != 0) {
+		sabi_set_command(sabi_config->commands.set_brightness, 0);
+	}
+
 	sabi_set_command(sabi_config->commands.set_brightness, user_level);
 }
 
@@ -666,6 +674,15 @@ static struct dmi_system_id __initdata samsung_dmi_table[] = {
 		},
 		.callback = dmi_check_cb,
 	},
+	{
+		.ident = "NC210/NC110",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "NC210/NC110"),
+			DMI_MATCH(DMI_BOARD_NAME, "NC210/NC110"),
+		},
+		.callback = dmi_check_cb,
+	},
 	{ },
 };
 MODULE_DEVICE_TABLE(dmi, samsung_dmi_table);