[POWERPC] Fix for via-pmu based backlight control

This fixes a few issues with via-pmu based backlight control.

First, it fixes a sign problem with the setup of the backlight
curve since the `range' value there -can- (and will) go negative.

Then, it reworks the interaction between this and the via-pmu sleep
code to properly restore backlight on wakeup from sleep.

Signed-off-by: Benjamin Herrenschmidt <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

drivers/macintosh/via-pmu-backlight.c

···
 
 static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
 {
-	unsigned int i, flat, count, range = (max - min);
+	int i, flat, count, range = (max - min);
 
 	bl_curve[0] = off;
 
···
 	return pmulevel;
 }
 
-static int pmu_backlight_update_status(struct backlight_device *bd)
+static int __pmu_backlight_update_status(struct backlight_device *bd)
 {
 	struct adb_request req;
-	unsigned long flags;
 	int level = bd->props.brightness;
 
-	spin_lock_irqsave(&pmu_backlight_lock, flags);
-
-	/* Don't update brightness when sleeping */
-	if (sleeping)
-		goto out;
 
 	if (bd->props.power != FB_BLANK_UNBLANK ||
 	    bd->props.fb_blank != FB_BLANK_UNBLANK)
···
 		pmu_wait_complete(&req);
 	}
 
-out:
-	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
-
 	return 0;
 }
+
+static int pmu_backlight_update_status(struct backlight_device *bd)
+{
+	unsigned long flags;
+	int rc = 0;
+
+	spin_lock_irqsave(&pmu_backlight_lock, flags);
+	/* Don't update brightness when sleeping */
+	if (!sleeping)
+		rc = __pmu_backlight_update_status(bd);
+	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
+	return rc;
+}
+
 
 static int pmu_backlight_get_brightness(struct backlight_device *bd)
 {
···
 
 	spin_lock_irqsave(&pmu_backlight_lock, flags);
 	sleeping = sleep;
+	if (pmac_backlight) {
+		if (sleep) {
+			struct adb_request req;
+
+			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
+				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
+			pmu_wait_complete(&req);
+		} else
+			__pmu_backlight_update_status(pmac_backlight);
+	}
 	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
 }
 #endif /* CONFIG_PM */
···
 
 	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data);
 	if (IS_ERR(bd)) {
-		printk("pmubl: Backlight registration failed\n");
-		goto error;
+		printk(KERN_ERR "PMU Backlight registration failed\n");
+		return;
 	}
 	bd->props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
 	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
···
 	bd->props.power = FB_BLANK_UNBLANK;
 	backlight_update_status(bd);
 
-	printk("pmubl: Backlight initialized (%s)\n", name);
-
-	return;
-
-error:
-	return;
+	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
 }

drivers/macintosh/via-pmu.c

···
 	out_8(&via[IER], IER_SET | SR_INT | CB1_INT);
 }
 
-extern void pmu_backlight_set_sleep(int sleep);
-
 #define	GRACKLE_PM	(1<<7)
 #define GRACKLE_DOZE	(1<<5)
 #define	GRACKLE_NAP	(1<<4)
···
 #if defined(CONFIG_SUSPEND) && defined(CONFIG_PPC32)
 static void pmac_suspend_disable_irqs(void)
 {
-#ifdef CONFIG_PMAC_BACKLIGHT
-	/* Tell backlight code not to muck around with the chip anymore */
-	pmu_backlight_set_sleep(1);
-#endif
-
 	/* Call platform functions marked "on sleep" */
 	pmac_pfunc_i2c_suspend();
 	pmac_pfunc_base_suspend();
···
 		return error;
 
 	mdelay(100);
-
-#ifdef CONFIG_PMAC_BACKLIGHT
-	/* Tell backlight code it can use the chip again */
-	pmu_backlight_set_sleep(0);
-#endif
 
 	return 0;
 }
···
 	if (state.event != PM_EVENT_SUSPEND || pmu_sys_suspended)
 		return 0;
 
-	/* Suspend PMU event interrupts */
+	/* Suspend PMU event interrupts */\
 	pmu_suspend();
-
 	pmu_sys_suspended = 1;
+
+#ifdef CONFIG_PMAC_BACKLIGHT
+	/* Tell backlight code not to muck around with the chip anymore */
+	pmu_backlight_set_sleep(1);
+#endif
+
 	return 0;
 }
 
···
 	pmu_request(&req, NULL, 2, PMU_SYSTEM_READY, 2);
 	pmu_wait_complete(&req);
 
+#ifdef CONFIG_PMAC_BACKLIGHT
+	/* Tell backlight code it can use the chip again */
+	pmu_backlight_set_sleep(0);
+#endif
 	/* Resume PMU event interrupts */
 	pmu_resume();
-
 	pmu_sys_suspended = 0;
 
 	return 0;

include/linux/pmu.h

···
 extern int pmu_present(void);
 extern int pmu_get_model(void);
 
+extern void pmu_backlight_set_sleep(int sleep);
+
 #define PMU_MAX_BATTERIES	2
 
 /* values for pmu_power_flags */