[DCON] Switch panel off cleanly to sleep mode on reboot.

[David Woodhouse]

Commit:     9d2bae412006aaf955e1a9056662fbbc47fc177a
Parent:     38a240ed6679c756244147104f019587a676a3b6
commit 9d2bae412006aaf955e1a9056662fbbc47fc177a
Author:     David Woodhouse <dwmw2 at infradead.org>
AuthorDate: Sun Nov 5 00:42:49 2006 +0800
Commit:     David Woodhouse <dwmw2 at infradead.org>
CommitDate: Sun Nov 5 00:42:49 2006 +0800

    [DCON] Switch panel off cleanly to sleep mode on reboot.
    
    Without this, we shut down extremely uncleanly and appear to put DC on
    the panel. This is a bad thing.
    
    Signed-off-by: David Woodhouse <dwmw2 at infradead.org>
---
 drivers/video/geode/gxfb_dcon.c |   20 +++++++++++++++++++-
 1 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/drivers/video/geode/gxfb_dcon.c b/drivers/video/geode/gxfb_dcon.c
index c7e7425..b269a88 100644
--- a/drivers/video/geode/gxfb_dcon.c
+++ b/drivers/video/geode/gxfb_dcon.c
@@ -23,6 +23,7 @@ #include <linux/delay.h>
 #include <linux/device.h>
 #include <asm/uaccess.h>
 #include <linux/ctype.h>
+#include <linux/reboot.h>
 #include <asm/tsc.h>
 
 #include "gxfb_dcon.h"
@@ -89,6 +90,7 @@ I2C_CLIENT_INSMOD;
 #define dcon_write(reg,val) i2c_smbus_write_word_data(dcon_client,reg,val)
 #define dcon_read(reg) i2c_smbus_read_word_data(dcon_client,reg)
 
+
 /* ===== API functions - these are called by a variety of users ==== */
 
 /* The current backlight value - this saves us some smbus traffic */
@@ -599,10 +601,24 @@ #endif
 		dcon_switched = 1;
 		wake_up(&dcon_wait_queue);
 	}
-
 	return IRQ_HANDLED;
 }
 
+int dcon_reboot_notify(struct notifier_block *nb, unsigned long foo, void *bar)
+{
+	if (dcon_client == NULL)
+		return 0;
+
+	/* Turn off the DCON. Entirely. */
+	dcon_write(DCON_REG_MODE, 0x12);
+	return 0;
+}
+
+struct notifier_block dcon_nb = {
+	.notifier_call = dcon_reboot_notify,
+	.priority = -1,
+};
+
 /* List of GPIOs that we care about:
    (in)  GPIO12   -- DCONBLNK
    (in)  GPIO[56] -- DCONSTAT[01]
@@ -708,11 +724,13 @@ int __init gxfb_dcon_init(void)
 	/* Attach the I2C driver */
 	i2c_add_driver(&dcon_driver);
 
+	register_reboot_notifier(&dcon_nb);
 	return 0;
 }
 
 void __exit gxfb_dcon_exit(void)
 {
+	unregister_reboot_notifier(&dcon_nb);
 	free_irq(DCON_IRQ, &dcon_driver);
 	i2c_del_driver(&dcon_driver);
 }