[PATCH] platform samsung-q10: use ACPI instead of direct EC calls

[Frederick van der Wyck <fvanderwyck@gmail.com>]

[ re-sending CC linux-acpi@vger.ketnel.org ]

This patch changes the Samsung Q10 backlight driver to use ACPI methods 
(the same ones as triggered by the brightness up/down function keys) 
instead of direct EC calls. The advantage is that the brightness setting 
is not lost on shutdown.

Signed-off-by: Frederick van der Wyck <fvanderwyck@gmail.com>
---
 drivers/platform/x86/Kconfig       |    2 +-
 drivers/platform/x86/samsung-q10.c |   77 ++++++++++++++++--------------------
 2 files changed, 35 insertions(+), 44 deletions(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 8577261..52aed6d 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -762,7 +762,7 @@ config INTEL_OAKTRAIL
 
 config SAMSUNG_Q10
 	tristate "Samsung Q10 Extras"
-	depends on SERIO_I8042
+	depends on ACPI
 	select BACKLIGHT_CLASS_DEVICE
 	---help---
 	  This driver provides support for backlight control on Samsung Q10
diff --git a/drivers/platform/x86/samsung-q10.c b/drivers/platform/x86/samsung-q10.c
index 1a90b62..e7caaa3 100644
--- a/drivers/platform/x86/samsung-q10.c
+++ b/drivers/platform/x86/samsung-q10.c
@@ -14,16 +14,14 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/backlight.h>
-#include <linux/i8042.h>
 #include <linux/dmi.h>
+#include <acpi/acpi_drivers.h>
 
-#define SAMSUNGQ10_BL_MAX_INTENSITY      255
-#define SAMSUNGQ10_BL_DEFAULT_INTENSITY  185
+#define SAMSUNGQ10_BL_MAX_INTENSITY 7
 
-#define SAMSUNGQ10_BL_8042_CMD           0xbe
-#define SAMSUNGQ10_BL_8042_DATA          { 0x89, 0x91 }
+#define EC_HID "PNP0C09"
 
-static int samsungq10_bl_brightness;
+static acpi_handle ec_handle;
 
 static bool force;
 module_param(force, bool, 0);
@@ -33,21 +31,26 @@ MODULE_PARM_DESC(force,
 static int samsungq10_bl_set_intensity(struct backlight_device *bd)
 {
 
-	int brightness = bd->props.brightness;
-	unsigned char c[3] = SAMSUNGQ10_BL_8042_DATA;
+	acpi_status status;
+	int i;
 
-	c[2] = (unsigned char)brightness;
-	i8042_lock_chip();
-	i8042_command(c, (0x30 << 8) | SAMSUNGQ10_BL_8042_CMD);
-	i8042_unlock_chip();
-	samsungq10_bl_brightness = brightness;
+	for (i = 0; i < SAMSUNGQ10_BL_MAX_INTENSITY; i++) {
+		status = acpi_evaluate_object(ec_handle, "_Q63", NULL, NULL);
+		if (ACPI_FAILURE(status))
+			return -EIO;
+	}
+	for (i = 0; i < bd->props.brightness; i++) {
+		status = acpi_evaluate_object(ec_handle, "_Q64", NULL, NULL);
+		if (ACPI_FAILURE(status))
+			return -EIO;
+	}
 
 	return 0;
 }
 
 static int samsungq10_bl_get_intensity(struct backlight_device *bd)
 {
-	return samsungq10_bl_brightness;
+	return bd->props.brightness;
 }
 
 static const struct backlight_ops samsungq10_bl_ops = {
@@ -55,28 +58,6 @@ static const struct backlight_ops samsungq10_bl_ops = {
 	.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 samsungq10_probe(struct platform_device *pdev)
 {
 
@@ -93,9 +74,6 @@ static int samsungq10_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, bd);
 
-	bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
-	samsungq10_bl_set_intensity(bd);
-
 	return 0;
 }
 
@@ -104,9 +82,6 @@ static int 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;
@@ -116,7 +91,6 @@ static struct platform_driver samsungq10_driver = {
 	.driver		= {
 		.name	= KBUILD_MODNAME,
 		.owner	= THIS_MODULE,
-		.pm	= &samsungq10_pm_ops,
 	},
 	.probe		= samsungq10_probe,
 	.remove		= samsungq10_remove,
@@ -167,11 +141,28 @@ static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
 };
 MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
 
+static acpi_status __init acpi_handle_locate_callback(acpi_handle handle,
+			u32 level, void *context, void **return_value)
+{
+	*(acpi_handle *)return_value = handle;
+
+	return AE_CTRL_TERMINATE;
+}
+
 static int __init samsungq10_init(void)
 {
+
+	acpi_status status;
+
 	if (!force && !dmi_check_system(samsungq10_dmi_table))
 		return -ENODEV;
 
+	status = acpi_get_devices(EC_HID, acpi_handle_locate_callback,
+				  NULL, &ec_handle);
+
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
 	samsungq10_device = platform_create_bundle(&samsungq10_driver,
 						   samsungq10_probe,
 						   NULL, 0, NULL, 0);
-- 
1.7.3.4