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path: root/drivers/platform/x86/apple-gmux.c
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Diffstat (limited to 'drivers/platform/x86/apple-gmux.c')
-rw-r--r--drivers/platform/x86/apple-gmux.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index 905fa01ac8df..c9db50729f6f 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -75,6 +75,18 @@ static inline u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
return inl(gmux_data->iostart + port);
}
+static inline u32 gmux_write32(struct apple_gmux_data *gmux_data, int port,
+ u32 val)
+{
+ int i;
+ u8 tmpval;
+
+ for (i = 0; i < 4; i++) {
+ tmpval = (val >> (i * 8)) & 0xff;
+ outb(tmpval, port + i);
+ }
+}
+
static int gmux_get_brightness(struct backlight_device *bd)
{
struct apple_gmux_data *gmux_data = bl_get_data(bd);
@@ -90,16 +102,7 @@ static int gmux_update_status(struct backlight_device *bd)
if (bd->props.state & BL_CORE_SUSPENDED)
return 0;
- /*
- * Older gmux versions require writing out lower bytes first then
- * setting the upper byte to 0 to flush the values. Newer versions
- * accept a single u32 write, but the old method also works, so we
- * just use the old method for all gmux versions.
- */
- gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
- gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 1, brightness >> 8);
- gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 2, brightness >> 16);
- gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 3, 0);
+ gmux_write32(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
return 0;
}