From e02a5548264bdf5ae9175bf1dd97760e6aac37d7 Mon Sep 17 00:00:00 2001
From: Leonid Lobachev <leonidl@google.com>
Date: Mon, 11 Feb 2019 13:26:44 -0800
Subject: [PATCH] Add sysfs node with temperature sensor reading.

Change-Id: Ic9a71f1b1aaee64b68224cdc20dcfe2980b9c7d8
---
 apex_driver.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/apex_driver.c b/apex_driver.c
index 8904551..e227017 100644
--- a/apex_driver.c
+++ b/apex_driver.c
@@ -67,6 +67,7 @@ enum sysfs_attribute_type {
 	ATTR_KERNEL_HIB_PAGE_TABLE_SIZE,
 	ATTR_KERNEL_HIB_SIMPLE_PAGE_TABLE_SIZE,
 	ATTR_KERNEL_HIB_NUM_ACTIVE_PAGES,
+	ATTR_TEMP,
 };
 
 /*
@@ -98,6 +99,9 @@ enum apex_bar2_regs {
 	APEX_BAR2_REG_USER_HIB_DMA_PAUSED = 0x486E0,
 	APEX_BAR2_REG_IDLEGENERATOR_IDLEGEN_IDLEREGISTER = 0x4A000,
 	APEX_BAR2_REG_KERNEL_HIB_PAGE_TABLE = 0x50000,
+	APEX_BAR2_REG_OMC0_D0 = 0x01a0d0,
+	APEX_BAR2_REG_OMC0_D8 = 0x01a0d8,
+	APEX_BAR2_REG_OMC0_DC = 0x01a0dc,
 
 	/* Error registers - Used mostly for debug */
 	APEX_BAR2_REG_USER_HIB_ERROR_STATUS = 0x86f0,
@@ -601,6 +605,15 @@ static ssize_t sysfs_show(struct device *device, struct device_attribute *attr,
 				gasket_page_table_num_active_pages(
 					gasket_dev->page_table[0]));
 		break;
+	case ATTR_TEMP:
+		// Read temperature
+		ret = gasket_dev_read_32(gasket_dev, APEX_BAR_INDEX,
+						APEX_BAR2_REG_OMC0_DC);
+		ret = (ret >> 16) & ((1 << 10) - 1);
+		// Remap to millicelsius (rough calculation)
+		ret = (((662 - ret) * 1000 / 4 + 500) * 10 + 500) / 10;
+		ret = snprintf(buf, PAGE_SIZE, "%i\n", ret);
+		break;
 	default:
 		dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
 			attr->attr.name);
@@ -620,6 +633,7 @@ static struct gasket_sysfs_attribute apex_sysfs_attrs[] = {
 			ATTR_KERNEL_HIB_SIMPLE_PAGE_TABLE_SIZE),
 	GASKET_SYSFS_RO(node_0_num_mapped_pages, sysfs_show,
 			ATTR_KERNEL_HIB_NUM_ACTIVE_PAGES),
+	GASKET_SYSFS_RO(temp, sysfs_show, ATTR_TEMP),
 	GASKET_END_OF_ATTR_ARRAY
 };
 
@@ -688,6 +702,20 @@ static int apex_pci_probe(struct pci_dev *pci_dev,
 		goto remove_device;
 	}
 
+	// Enable thermal sensor clocks
+	gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
+					APEX_BAR2_REG_OMC0_D0, 0x1, 1, 7);
+
+	// Enable thermal sensor (ENAD ENVR ENBG)
+	gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
+					APEX_BAR2_REG_OMC0_D8, 0x7, 3, 0);
+
+	// Enable OMC thermal sensor controller
+	// This bit should be asserted 100 us after ENAD ENVR ENBG
+	schedule_timeout(usecs_to_jiffies(100));
+	gasket_read_modify_write_32(gasket_dev, APEX_BAR_INDEX,
+					APEX_BAR2_REG_OMC0_DC, 0x1, 1, 0);
+
 	ret = gasket_sysfs_create_entries(gasket_dev->dev_info.device,
 					  apex_sysfs_attrs);
 	if (ret)