[PATCH] Rewritten backlight infrastructure for portable Apple computers

This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers.  Backward compatibility is retained.  A sysfs
interface allows userland to control the brightness with more steps than
before.  Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.

[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/drivers/macintosh/via-pmu-backlight.c b/drivers/macintosh/via-pmu-backlight.c
new file mode 100644
index 00000000000..b42d05f2aaf
--- /dev/null
+++ b/drivers/macintosh/via-pmu-backlight.c
@@ -0,0 +1,150 @@
+/*
+ * Backlight code for via-pmu
+ *
+ * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
+ * Copyright (C) 2001-2002 Benjamin Herrenschmidt
+ * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
+ *
+ */
+
+#include <asm/ptrace.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <asm/backlight.h>
+#include <asm/prom.h>
+
+#define MAX_PMU_LEVEL 0xFF
+
+static struct device_node *vias;
+static struct backlight_properties pmu_backlight_data;
+
+static int pmu_backlight_get_level_brightness(struct fb_info *info,
+		int level)
+{
+	int pmulevel;
+
+	/* Get and convert the value */
+	mutex_lock(&info->bl_mutex);
+	pmulevel = info->bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
+	mutex_unlock(&info->bl_mutex);
+
+	if (pmulevel < 0)
+		pmulevel = 0;
+	else if (pmulevel > MAX_PMU_LEVEL)
+		pmulevel = MAX_PMU_LEVEL;
+
+	return pmulevel;
+}
+
+static int pmu_backlight_update_status(struct backlight_device *bd)
+{
+	struct fb_info *info = class_get_devdata(&bd->class_dev);
+	struct adb_request req;
+	int pmulevel, level = bd->props->brightness;
+
+	if (vias == NULL)
+		return -ENODEV;
+
+	if (bd->props->power != FB_BLANK_UNBLANK ||
+	    bd->props->fb_blank != FB_BLANK_UNBLANK)
+		level = 0;
+
+	pmulevel = pmu_backlight_get_level_brightness(info, level);
+
+	pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
+	pmu_wait_complete(&req);
+
+	pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
+		PMU_POW_BACKLIGHT | (level > 0 ? PMU_POW_ON : PMU_POW_OFF));
+	pmu_wait_complete(&req);
+
+	return 0;
+}
+
+static int pmu_backlight_get_brightness(struct backlight_device *bd)
+{
+	return bd->props->brightness;
+}
+
+static struct backlight_properties pmu_backlight_data = {
+	.owner		= THIS_MODULE,
+	.get_brightness	= pmu_backlight_get_brightness,
+	.update_status	= pmu_backlight_update_status,
+	.max_brightness	= (FB_BACKLIGHT_LEVELS - 1),
+};
+
+void __init pmu_backlight_init(struct device_node *in_vias)
+{
+	struct backlight_device *bd;
+	struct fb_info *info;
+	char name[10];
+	int level, autosave;
+
+	vias = in_vias;
+
+	/* Special case for the old PowerBook since I can't test on it */
+	autosave =
+		machine_is_compatible("AAPL,3400/2400") ||
+		machine_is_compatible("AAPL,3500");
+
+	if (!autosave &&
+	    !pmac_has_backlight_type("pmu") &&
+	    !machine_is_compatible("AAPL,PowerBook1998") &&
+	    !machine_is_compatible("PowerBook1,1"))
+		return;
+
+	/* Actually, this is a hack, but I don't know of a better way
+	 * to get the first framebuffer device.
+	 */
+	info = registered_fb[0];
+	if (!info) {
+		printk("pmubl: No framebuffer found\n");
+		goto error;
+	}
+
+	snprintf(name, sizeof(name), "pmubl%d", info->node);
+
+	bd = backlight_device_register(name, info, &pmu_backlight_data);
+	if (IS_ERR(bd)) {
+		printk("pmubl: Backlight registration failed\n");
+		goto error;
+	}
+
+	mutex_lock(&info->bl_mutex);
+	info->bl_dev = bd;
+	fb_bl_default_curve(info, 0x7F, 0x46, 0x0E);
+	mutex_unlock(&info->bl_mutex);
+
+	level = pmu_backlight_data.max_brightness;
+
+	if (autosave) {
+		/* read autosaved value if available */
+		struct adb_request req;
+		pmu_request(&req, NULL, 2, 0xd9, 0);
+		pmu_wait_complete(&req);
+
+		mutex_lock(&info->bl_mutex);
+		level = pmac_backlight_curve_lookup(info,
+				(req.reply[0] >> 4) *
+				pmu_backlight_data.max_brightness / 15);
+		mutex_unlock(&info->bl_mutex);
+	}
+
+	up(&bd->sem);
+	bd->props->brightness = level;
+	bd->props->power = FB_BLANK_UNBLANK;
+	bd->props->update_status(bd);
+	down(&bd->sem);
+
+	mutex_lock(&pmac_backlight_mutex);
+	if (!pmac_backlight)
+		pmac_backlight = bd;
+	mutex_unlock(&pmac_backlight_mutex);
+
+	printk("pmubl: Backlight initialized (%s)\n", name);
+
+	return;
+
+error:
+	return;
+}