--- /dev/null
+/*
+ * Miscellaneous procedures for dealing with the PowerMac hardware.
+ * Contains support for the backlight.
+ *
+ * Copyright (C) 2000 Benjamin Herrenschmidt
+ * Copyright (C) 2006 Michael Hanselmann <linux-kernel@hansmi.ch>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/fb.h>
+#include <linux/backlight.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <linux/atomic.h>
+#include <linux/export.h>
+#include <asm/prom.h>
+#include <asm/backlight.h>
+
+#define OLD_BACKLIGHT_MAX 15
+
+static void pmac_backlight_key_worker(struct work_struct *work);
+static void pmac_backlight_set_legacy_worker(struct work_struct *work);
+
+static DECLARE_WORK(pmac_backlight_key_work, pmac_backlight_key_worker);
+static DECLARE_WORK(pmac_backlight_set_legacy_work, pmac_backlight_set_legacy_worker);
+
+/* Although these variables are used in interrupt context, it makes no sense to
+ * protect them. No user is able to produce enough key events per second and
+ * notice the errors that might happen.
+ */
+static int pmac_backlight_key_queued;
+static int pmac_backlight_set_legacy_queued;
+
+/* The via-pmu code allows the backlight to be grabbed, in which case the
+ * in-kernel control of the brightness needs to be disabled. This should
+ * only be used by really old PowerBooks.
+ */
+static atomic_t kernel_backlight_disabled = ATOMIC_INIT(0);
+
+/* Protect the pmac_backlight variable below.
+ You should hold this lock when using the pmac_backlight pointer to
+ prevent its potential removal. */
+DEFINE_MUTEX(pmac_backlight_mutex);
+
+/* Main backlight storage
+ *
+ * Backlight drivers in this variable are required to have the "ops"
+ * attribute set and to have an update_status function.
+ *
+ * We can only store one backlight here, but since Apple laptops have only one
+ * internal display, it doesn't matter. Other backlight drivers can be used
+ * independently.
+ *
+ */
+struct backlight_device *pmac_backlight;
+
+int pmac_has_backlight_type(const char *type)
+{
+ struct device_node* bk_node = of_find_node_by_name(NULL, "backlight");
+
+ if (bk_node) {
+ const char *prop = of_get_property(bk_node,
+ "backlight-control", NULL);
+ if (prop && strncmp(prop, type, strlen(type)) == 0) {
+ of_node_put(bk_node);
+ return 1;
+ }
+ of_node_put(bk_node);
+ }
+
+ return 0;
+}
+
+int pmac_backlight_curve_lookup(struct fb_info *info, int value)
+{
+ int level = (FB_BACKLIGHT_LEVELS - 1);
+
+ if (info && info->bl_dev) {
+ int i, max = 0;
+
+ /* Look for biggest value */
+ for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
+ max = max((int)info->bl_curve[i], max);
+
+ /* Look for nearest value */
+ for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
+ int diff = abs(info->bl_curve[i] - value);
+ if (diff < max) {
+ max = diff;
+ level = i;
+ }
+ }
+
+ }
+
+ return level;
+}
+
+static void pmac_backlight_key_worker(struct work_struct *work)
+{
+ if (atomic_read(&kernel_backlight_disabled))
+ return;
+
+ mutex_lock(&pmac_backlight_mutex);
+ if (pmac_backlight) {
+ struct backlight_properties *props;
+ int brightness;
+
+ props = &pmac_backlight->props;
+
+ brightness = props->brightness +
+ ((pmac_backlight_key_queued?-1:1) *
+ (props->max_brightness / 15));
+
+ if (brightness < 0)
+ brightness = 0;
+ else if (brightness > props->max_brightness)
+ brightness = props->max_brightness;
+
+ props->brightness = brightness;
+ backlight_update_status(pmac_backlight);
+ }
+ mutex_unlock(&pmac_backlight_mutex);
+}
+
+/* This function is called in interrupt context */
+void pmac_backlight_key(int direction)
+{
+ if (atomic_read(&kernel_backlight_disabled))
+ return;
+
+ /* we can receive multiple interrupts here, but the scheduled work
+ * will run only once, with the last value
+ */
+ pmac_backlight_key_queued = direction;
+ schedule_work(&pmac_backlight_key_work);
+}
+
+static int __pmac_backlight_set_legacy_brightness(int brightness)
+{
+ int error = -ENXIO;
+
+ mutex_lock(&pmac_backlight_mutex);
+ if (pmac_backlight) {
+ struct backlight_properties *props;
+
+ props = &pmac_backlight->props;
+ props->brightness = brightness *
+ (props->max_brightness + 1) /
+ (OLD_BACKLIGHT_MAX + 1);
+
+ if (props->brightness > props->max_brightness)
+ props->brightness = props->max_brightness;
+ else if (props->brightness < 0)
+ props->brightness = 0;
+
+ backlight_update_status(pmac_backlight);
+
+ error = 0;
+ }
+ mutex_unlock(&pmac_backlight_mutex);
+
+ return error;
+}
+
+static void pmac_backlight_set_legacy_worker(struct work_struct *work)
+{
+ if (atomic_read(&kernel_backlight_disabled))
+ return;
+
+ __pmac_backlight_set_legacy_brightness(pmac_backlight_set_legacy_queued);
+}
+
+/* This function is called in interrupt context */
+void pmac_backlight_set_legacy_brightness_pmu(int brightness) {
+ if (atomic_read(&kernel_backlight_disabled))
+ return;
+
+ pmac_backlight_set_legacy_queued = brightness;
+ schedule_work(&pmac_backlight_set_legacy_work);
+}
+
+int pmac_backlight_set_legacy_brightness(int brightness)
+{
+ return __pmac_backlight_set_legacy_brightness(brightness);
+}
+
+int pmac_backlight_get_legacy_brightness()
+{
+ int result = -ENXIO;
+
+ mutex_lock(&pmac_backlight_mutex);
+ if (pmac_backlight) {
+ struct backlight_properties *props;
+
+ props = &pmac_backlight->props;
+
+ result = props->brightness *
+ (OLD_BACKLIGHT_MAX + 1) /
+ (props->max_brightness + 1);
+ }
+ mutex_unlock(&pmac_backlight_mutex);
+
+ return result;
+}
+
+void pmac_backlight_disable()
+{
+ atomic_inc(&kernel_backlight_disabled);
+}
+
+void pmac_backlight_enable()
+{
+ atomic_dec(&kernel_backlight_disabled);
+}
+
+EXPORT_SYMBOL_GPL(pmac_backlight);
+EXPORT_SYMBOL_GPL(pmac_backlight_mutex);
+EXPORT_SYMBOL_GPL(pmac_has_backlight_type);
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