first and last commit

drivers/backlight/lm3534/library.mk

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+# Copyright (C) 2015 Apple Inc. All rights reserved.
+#
+# This document is the property of Apple Inc.
+# It is considered confidential and proprietary.
+#
+# This document may not be reproduced or transmitted in any form,
+# in whole or in part, without the express written permission of
+# Apple Inc.
+#
+
+LIBLM3534_DIR		:=	$(GET_LOCAL_DIR)
+LIBLM3534_BUILD		:=	$(call TOLIBDIR,$(LIBLM3534_DIR)/LIBLM3534.a)
+COMMONLIBS		+=	LIBLM3534
+
+# Only process the remainder of the makefile if we are building libraries
+#
+ifeq ($(MAKEPHASE),libraries)
+
+LIBLM3534_OBJS		:=	$(LIBLM3534_DIR)/lm3534.o
+
+LIBLM3534_OBJS		:=	$(call TOLIBOBJDIR,$(LIBLM3534_OBJS))
+
+ALL_DEPS		+=	$(LIBLM3534_OBJS:%o=%d)
+
+$(LIBLM3534_BUILD):	$(LIBLM3534_OBJS)
+
+endif

drivers/backlight/lm3534/lm3534.c

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+/*
+ * Copyright (C) 2011-2015 Apple Inc. All rights reserved.
+ *
+ * This document is the property of Apple Inc.
+ * It is considered confidential and proprietary.
+ *
+ * This document may not be reproduced or transmitted in any form,
+ * in whole or in part, without the express written permission of
+ * Apple Inc.
+ */
+#include <debug.h>
+#include <drivers/iic.h>
+#include <lib/mib.h>
+#include <sys.h>
+#include <target.h>
+
+#define LM3534_GPR		(0x10)
+#define LM3534_DFS		(0x11)
+#define LM3534_RRR		(0x12)
+#define LM3534_BRL		(0x13)
+#define LM3534_BRH		(0x14)
+#define LM3534_AFT		(0x32)
+
+static bool lm3534_probed;
+static uint32_t lm3534_address[2];
+static uint32_t lm3534_bus[2];
+static bool lm3534_present[2];
+
+int lm3534_backlight_probe(void)
+{
+	uint8_t data[1];
+
+	if (lm3534_probed)
+		return lm3534_present[0] ? 0 : -1;
+	lm3534_probed = true;
+
+	lm3534_bus[0] = mib_get_u32(kMIBTargetBacklight0I2CBus);
+	lm3534_bus[1] = mib_get_u32_opt(kMIBTargetBacklight1I2CBus, (uint32_t)-1);
+	lm3534_address[0] = mib_get_u32(kMIBTargetBacklight0I2CAddress);
+	lm3534_address[1] = mib_get_u32_opt(kMIBTargetBacklight1I2CAddress, (uint32_t)-1);
+
+	for (unsigned i = 0; i < 2; i++) {
+		if (lm3534_bus[i] == (uint32_t)-1) {
+			break;
+		}
+		
+		dprintf(DEBUG_SPEW, "lm3534: probing backlight controller %u at i2c%u address 0x%x\n", i, lm3534_bus[i], lm3534_address[i]);
+
+		// Probe for the LM3534 by reading a register
+		data[0] = LM3534_GPR;
+		if (iic_read(lm3534_bus[i], lm3534_address[i], data, 1, data, 1, IIC_NORMAL) == 0) {
+			// Mark the LM3534 as present
+			lm3534_present[i] = true;
+		}
+
+		if (!lm3534_present[i]) {
+			if (i == 0) {
+				// Return an error if the first LM3534 is not present
+				dprintf(DEBUG_INFO, "lm3534: failed to detect backlight controller, bailing\n");
+				return -1;
+			} else {
+				// Depending on the display card attached, the second backlight
+				// controller may or may not exist. Its absense is not fatal.
+				dprintf(DEBUG_INFO, "lm3534: failed to detect second backlight controller, ignoring\n");
+			}
+		} else {
+			dprintf(DEBUG_SPEW, "lm3534: successfully probed backlight controller %u with value 0x%x\n", i, data[0]);
+		}
+	}
+
+	return 0;
+}
+
+int lm3534_backlight_enable(uint32_t backlight_level)
+{
+	uint8_t data[2];
+
+	if (!lm3534_probed) {
+		lm3534_backlight_probe();
+	}
+
+	if (!lm3534_present[0])
+		return -1;
+
+	for (unsigned i = 0; i < 2; i++) {
+		if (!lm3534_present[i])
+			break;
+
+		// Configure the backlight for defaults expect no ramp
+		dprintf(DEBUG_SPEW, "lm3534: setting backlight controller %u to level %u\n", i, backlight_level);
+		data[0] = LM3534_GPR;
+		data[1] = target_lm3534_gpr(i);
+
+		// <rdar://problem/20615779>
+		// Dark boot may hand off to the OS with backlight disabled, but the OS backlight driver depends on iBoot
+		// to configure the backlight even if it's left disabled.
+		if (backlight_level == 0)
+			data[1] &= ~0x1; // bit 0: chip enable
+
+		iic_write(lm3534_bus[i], lm3534_address[i], data, 2);
+
+		uint32_t thresholdValue = 0;
+		if(mib_exists(kMIBTargetBacklightAutoFreqThresh, &thresholdValue)) {
+			dprintf(DEBUG_SPEW, "lm3534: Modify Auto-Frequency Threshold (0x%x)\n", thresholdValue);
+			data[0] = LM3534_AFT;
+			data[1] = thresholdValue;
+			iic_write(lm3534_bus[i], lm3534_address[i], data, 2);
+		}
+	}
+
+	// <rdar://problem/11055346> Not seeing the battery trap icon
+	// Delay to ensure that the LM3534 settings are processed before issuing dwi transaction
+	spin(600);
+
+	extern int dwi_send_backlight_command(uint32_t backlight_command, uint32_t backlight_level);
+
+	dwi_send_backlight_command(0xA, backlight_level);
+
+	return 0;
+}

drivers/backlight/lm3534/rules.mk

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+# Copyright (C) 2011-2015 Apple Inc. All rights reserved.
+#
+# This document is the property of Apple Inc.
+# It is considered confidential and proprietary.
+#
+# This document may not be reproduced or transmitted in any form,
+# in whole or in part, without the express written permission of
+# Apple Inc.
+#
+LOCAL_DIR := $(GET_LOCAL_DIR)
+
+OPTIONS += \
+	WITH_HW_LM3534=1
+
+LIBRARY_MODULES	+= drivers/backlight/lm3534