[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 000000000000..b42d05f2aaff
--- /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;
+}