Temperature polling and temporal correction

A temperature polling task is added to achieve temporal correction and
also reduce the latency of reading temperature.

Factor out sensor specific part to keep code clean.

Signed-off-by: Vic Yang <victoryang@chromium.org>

BUG=chrome-os-partner:7801
TEST=On link, 'temps' shows all temperature readings.
Cover each sensor with hand and see object temperature rise.
Compilation succeeded on bds/adv/daisy/discovery.

Change-Id: I3c44c8b2e3ab2aa9ce640d3fc25e7fba56534b86

17 files changed, 396 insertions, 278 deletions

diff --git a/Makefile.toolchain b/Makefile.toolchain
index 6f75b65a45..adfc4b1fcf 100644
--- a/Makefile.toolchain
+++ b/Makefile.toolchain
@@ -25,7 +25,7 @@ CFLAGS_WARN=-Wall -Wundef -Wstrict-prototypes -Wno-trigraphs              \
 CFLAGS_DEBUG= -g
 CFLAGS_INCLUDE=$(foreach i,$(includes),-I$(i) )
 CFLAGS_DEFINE=-DOUTDIR=$(out) -DCHIP=$(CHIP) -DTASKFILE=$(PROJECT).tasklist \
-              -DBOARD=$(BOARD) -DBOARD_$(BOARD) -DCORE=$(CORE)
+              -DBOARD=$(BOARD) -DBOARD_$(BOARD) -DCORE=$(CORE) -DCHIP_$(CHIP)
 CPPFLAGS=$(CFLAGS_DEFINE) $(CFLAGS_INCLUDE)
 CFLAGS=$(CPPFLAGS) $(CFLAGS_CPU) $(CFLAGS_DEBUG) $(CFLAGS_WARN)
 BUILD_CFLAGS=$(CPPFLAGS) -O3 $(CFLAGS_DEBUG) $(CFLAGS_WARN)
diff --git a/board/bds/board.h b/board/bds/board.h
index 7bd484edaf..dc96aa73c2 100644
--- a/board/bds/board.h
+++ b/board/bds/board.h
@@ -8,6 +8,9 @@
 #ifndef __BOARD_H
 #define __BOARD_H
 
+/* Config flags */
+#define CONFIG_TMP006
+
 /* 66.667 Mhz clock frequency */
 #define CPU_CLOCK  66666667
 
@@ -125,10 +128,13 @@ enum gpio_signal {
 enum temp_sensor_id {
   TEMP_SENSOR_EC_INTERNAL = 0, /* EC internal temperature sensor */
   TEMP_SENSOR_CASE_DIE,
+  TEMP_SENSOR_OBJECT,
 
   TEMP_SENSOR_COUNT
 };
 
+#define TMP006_COUNT 1
+
 void configure_board(void);
 
 #endif /* __BOARD_H */
diff --git a/board/bds/board_temp_sensor.c b/board/bds/board_temp_sensor.c
index 2efa002cb9..5bc9a154f5 100644
--- a/board/bds/board_temp_sensor.c
+++ b/board/bds/board_temp_sensor.c
@@ -9,14 +9,22 @@
 #include "chip_temp_sensor.h"
 #include "board.h"
 #include "i2c.h"
+#include "tmp006.h"
+#include "util.h"
 
 #define TEMP_CASE_DIE_REG_ADDR ((0x40 << 1) | I2C_FLAG_BIG_ENDIAN)
 #define TEMP_CASE_DIE_ADDR \
 	TMP006_ADDR(I2C_PORT_THERMAL, TEMP_CASE_DIE_REG_ADDR)
 
+/* Temperature sensors data. Must be in the same order as enum
+ * temp_sensor_id.
+ */
 const struct temp_sensor_t temp_sensors[TEMP_SENSOR_COUNT] = {
-	{"ECInternal", TEMP_SENSOR_NO_ADDR,
-		chip_temp_sensor_read, TEMP_SENSOR_NO_PRINT},
-	{"CaseDie", TEMP_CASE_DIE_ADDR,
-		temp_sensor_tmp006_read_die_temp, temp_sensor_tmp006_print}
+	{"ECInternal", chip_temp_sensor_get_val, 0},
+	{"CaseDie", tmp006_get_val, 0},
+	{"Object", tmp006_get_val, 0},
+};
+
+const struct tmp006_t tmp006_sensors[TMP006_COUNT] = {
+	{"TMP006", TEMP_CASE_DIE_ADDR},
 };
diff --git a/board/bds/ec.tasklist b/board/bds/ec.tasklist
index a56e6769e1..a17d39199f 100644
--- a/board/bds/ec.tasklist
+++ b/board/bds/ec.tasklist
@@ -15,6 +15,7 @@
  */
 #define CONFIG_TASK_LIST \
 	TASK(WATCHDOG, watchdog_task, NULL) \
+	TASK(TEMPSENSOR, temp_sensor_task, NULL) \
 	TASK(KEYSCAN, keyboard_scan_task, NULL) \
 	TASK(POWERBTN, power_button_task, NULL) \
 	TASK(X86POWER, x86_power_task, NULL) \
diff --git a/board/link/board.h b/board/link/board.h
index eec67588c9..d061e90f63 100644
--- a/board/link/board.h
+++ b/board/link/board.h
@@ -10,6 +10,7 @@
 
 /* Optional features */
 #define CONFIG_PECI
+#define CONFIG_TMP006
 
 /* 66.667 Mhz clock frequency */
 #define CPU_CLOCK  66666667
@@ -170,12 +171,20 @@ enum gpio_signal {
 enum temp_sensor_id {
 	/* I2C die temperature sensor near CPU */
 	TEMP_SENSOR_I2C_DIE_NEAR_CPU = 0,
-	/* PCH temperature sensor */
+	/* I2C object temperature sensor near CPU */
+	TEMP_SENSOR_I2C_CPU,
+	/* I2C die temperature sensor near PCH */
 	TEMP_SENSOR_I2C_DIE_NEAR_PCH,
-	/* DDR memory temperature sensor */
+	/* I2C object temperature sensor near PCH */
+	TEMP_SENSOR_I2C_PCH,
+	/* I2C die temperature sensor near DDR memory */
 	TEMP_SENSOR_I2C_DIE_NEAR_DDR,
-	/* Battery charger temperature sensor */
+	/* I2C object temperature sensor near CPU */
+	TEMP_SENSOR_I2C_DDR,
+	/* I2C die temperature sensor near battery charger */
 	TEMP_SENSOR_I2C_DIE_NEAR_CHARGER,
+	/* I2C object temperature sensor near CPU */
+	TEMP_SENSOR_I2C_CHARGER,
 	/* EC internal temperature sensor */
 	TEMP_SENSOR_EC_INTERNAL,
 	/* CPU die temperature via PECI */
@@ -186,6 +195,9 @@ enum temp_sensor_id {
 	TEMP_SENSOR_COUNT
 };
 
+/* The number of TMP006 sensor chips on the board. */
+#define TMP006_COUNT 4
+
 void configure_board(void);
 
 #endif /* __BOARD_H */
diff --git a/board/link/board_temp_sensor.c b/board/link/board_temp_sensor.c
index a8f3fae104..f8d3f93c2c 100644
--- a/board/link/board_temp_sensor.c
+++ b/board/link/board_temp_sensor.c
@@ -10,6 +10,8 @@
 #include "board.h"
 #include "i2c.h"
 #include "peci.h"
+#include "tmp006.h"
+#include "util.h"
 
 #define TEMP_CPU_REG_ADDR ((0x40 << 1) | I2C_FLAG_BIG_ENDIAN)
 #define TEMP_PCH_REG_ADDR ((0x41 << 1) | I2C_FLAG_BIG_ENDIAN)
@@ -25,16 +27,21 @@
  * temp_sensor_id.
  */
 const struct temp_sensor_t temp_sensors[TEMP_SENSOR_COUNT] = {
-	{"I2C_CPU", TEMP_CPU_ADDR,
-	 temp_sensor_tmp006_read_die_temp, temp_sensor_tmp006_print},
-	{"I2C_PCH", TEMP_PCH_ADDR,
-	 temp_sensor_tmp006_read_die_temp, temp_sensor_tmp006_print},
-	{"I2C_DDR", TEMP_DDR_ADDR,
-	 temp_sensor_tmp006_read_die_temp, temp_sensor_tmp006_print},
-	{"I2C_Charger", TEMP_CHARGER_ADDR,
-	 temp_sensor_tmp006_read_die_temp, temp_sensor_tmp006_print},
-	{"ECInternal", TEMP_SENSOR_NO_ADDR,
-	 chip_temp_sensor_read, TEMP_SENSOR_NO_PRINT},
-	{"PECI", TEMP_SENSOR_NO_ADDR,
-	 peci_temp_sensor_read, TEMP_SENSOR_NO_PRINT},
+	{"I2C_CPU-Die", tmp006_get_val, 0},
+	{"I2C_CPU-Object", tmp006_get_val, 1},
+	{"I2C_PCH-Die", tmp006_get_val, 2},
+	{"I2C_PCH-Object", tmp006_get_val, 3},
+	{"I2C_DDR-Die", tmp006_get_val, 4},
+	{"I2C_DDR-Object", tmp006_get_val, 5},
+	{"I2C_Charger-Die", tmp006_get_val, 6},
+	{"I2C_Charger-Object", tmp006_get_val, 7},
+	{"ECInternal", chip_temp_sensor_get_val, 0},
+	{"PECI", peci_temp_sensor_get_val, 0},
+};
+
+const struct tmp006_t tmp006_sensors[TMP006_COUNT] = {
+	{"CPU", TEMP_CPU_ADDR},
+	{"PCH", TEMP_PCH_ADDR},
+	{"DDR", TEMP_DDR_ADDR},
+	{"Charger", TEMP_CHARGER_ADDR},
 };
diff --git a/board/link/ec.tasklist b/board/link/ec.tasklist
index a56e6769e1..a17d39199f 100644
--- a/board/link/ec.tasklist
+++ b/board/link/ec.tasklist
@@ -15,6 +15,7 @@
  */
 #define CONFIG_TASK_LIST \
 	TASK(WATCHDOG, watchdog_task, NULL) \
+	TASK(TEMPSENSOR, temp_sensor_task, NULL) \
 	TASK(KEYSCAN, keyboard_scan_task, NULL) \
 	TASK(POWERBTN, power_button_task, NULL) \
 	TASK(X86POWER, x86_power_task, NULL) \
diff --git a/chip/lm4/chip_temp_sensor.c b/chip/lm4/chip_temp_sensor.c
index b81d2b5383..89cac21765 100644
--- a/chip/lm4/chip_temp_sensor.c
+++ b/chip/lm4/chip_temp_sensor.c
@@ -9,9 +9,18 @@
 #include "board.h"
 #include "temp_sensor.h"
 
-int chip_temp_sensor_read(const struct temp_sensor_t* sensor)
+static int last_val;
+
+int chip_temp_sensor_poll(void)
+{
+	last_val = adc_read_channel(ADC_CH_EC_TEMP);
+
+	return EC_SUCCESS;
+}
+
+int chip_temp_sensor_get_val(int idx)
 {
-	return adc_read_channel(ADC_CH_EC_TEMP);
+	return last_val;
 }
 
 int chip_temp_sensor_init(void)
diff --git a/chip/lm4/peci.c b/chip/lm4/peci.c
index eb82989be3..732a45b24d 100644
--- a/chip/lm4/peci.c
+++ b/chip/lm4/peci.c
@@ -28,6 +28,7 @@
 #define PECI_TD_FET_NS 25  /* Guess; TODO: what is real delay */
 #define PECI_TD_INT_NS 80
 
+static int last_temp_val;
 
 /* Configures the GPIOs for the PECI module. */
 static void configure_gpios(void)
@@ -50,10 +51,21 @@ int peci_get_cpu_temp(void)
 	return v >> 6;
 }
 
+int peci_temp_sensor_poll(void)
+{
+	int val = peci_get_cpu_temp();
+
+	if (val > 0) {
+		last_temp_val = val;
+		return EC_SUCCESS;
+	}
+	else
+		return EC_ERROR_UNKNOWN;
+}
 
-int peci_temp_sensor_read(const struct temp_sensor_t* sensor)
+int peci_temp_sensor_get_val(int idx)
 {
-	return peci_get_cpu_temp();
+	return last_temp_val;
 }
 
 /*****************************************************************************/
diff --git a/common/build.mk b/common/build.mk
index a04fe3c11a..b6e32dfd73 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -16,6 +16,7 @@ common-$(CONFIG_TASK_GAIAPOWER)+=gaia_power.o
 common-$(CONFIG_FLASH)+=flash_commands.o
 common-$(CONFIG_PWM)+=pwm_commands.o
 common-$(CONFIG_TEMP_SENSOR)+=temp_sensor.o temp_sensor_commands.o
+common-$(CONFIG_TMP006)+=tmp006.o
 common-$(CONFIG_LIGHTBAR)+=leds.o
 
 # Board driver modules
diff --git a/common/main.c b/common/main.c
index 7058aad009..f342bad9a0 100644
--- a/common/main.c
+++ b/common/main.c
@@ -30,6 +30,7 @@
 #include "system.h"
 #include "task.h"
 #include "temp_sensor.h"
+#include "tmp006.h"
 #include "timer.h"
 #include "uart.h"
 #include "usb_charge.h"
diff --git a/common/temp_sensor.c b/common/temp_sensor.c
index 9313623213..cc7dc25599 100644
--- a/common/temp_sensor.c
+++ b/common/temp_sensor.c
@@ -11,9 +11,10 @@
 #include "util.h"
 #include "console.h"
 #include "board.h"
+#include "peci.h"
+#include "tmp006.h"
 #include "task.h"
-#include "fpu.h"
-#include "math.h"
+#include "chip_temp_sensor.h"
 
 /* Defined in board_temp_sensor.c. Must be in the same order as
  * in enum temp_sensor_id.
@@ -27,171 +28,31 @@ int temp_sensor_read(enum temp_sensor_id id)
 	if (id < 0 || id >= TEMP_SENSOR_COUNT)
 		return -1;
 	sensor = temp_sensors + id;
-	return sensor->read(sensor);
+	return sensor->read(sensor->idx);
 }
 
-int temp_sensor_tmp006_read_die_temp(const struct temp_sensor_t* sensor)
+void poll_all_sensors(void)
 {
-	int traw, t;
-	int rv;
-	int addr = sensor->addr;
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x01, &traw);
-	if (rv)
-		return -1;
-	t = (int)(int16_t)traw / 128;
-	return t + 273;
-}
-
-/* Calculate the remote object temperature.
- * Parameters:
- *     Tdie: Die temperature in 1/100 K.
- *     Vobj: Voltage read from register 0. In nV.
- *     S0:   Sensitivity factor in 1e-17.
- * Return:
- *     Object temperature in 1/100 K.
- */
-int temp_sensor_tmp006_calculate_object_temp(int Tdie_i, int Vobj_i, int S0_i)
-{
-#ifdef CONFIG_FPU
-	float Tdie, Vobj, S0;
-	float Tx, S, Vos, Vx, fv, Tobj, T4;
-	int Tobj_i;
-
-	enable_fpu();
-
-	Tdie = (float)Tdie_i * 1e-2f;
-	Vobj = (float)Vobj_i * 1e-9f;
-	S0 = (float)S0_i * 1e-17f;
-
-	/* Calculate according to TMP006 users guide. */
-	Tx = Tdie - 298.15f;
-	/* S is the sensitivity */
-	S = S0 * (1.0f + 1.75e-3f * Tx - 1.678e-5f * Tx * Tx);
-	/* Vos is the offset voltage */
-	Vos = -2.94e-5f - 5.7e-7f * Tx + 4.63e-9f * Tx * Tx;
-	Vx = Vobj - Vos;
-	/* fv is Seebeck coefficient f(Vobj) */
-	fv = Vx + 13.4f * Vx * Vx;
-
-	T4 = Tdie * Tdie * Tdie * Tdie + fv / S;
-	Tobj = sqrtf(sqrtf(T4));
-	Tobj_i = (int32_t)(Tobj * 100.0f);
-
-	disable_fpu(Tobj_i);
-
-	return Tobj_i;
-#else
-	/* This is the fixed-point version of object temperature calculation.
-	 * Should be accurate but it is hard to prevent and debug
-	 * overflow/underflow problem. Only use this version if there is no
-	 * FPU support.
-	 * Division is delayed when possible to preserve precision, but should
-	 * not cause overflow.
-	 * Assuming Tdie is between 200K and 400K, and S0 between 3e-14 and
-	 * 9e-14, the maximum value during the calculation should be less than
-	 * (1 << 30), which fits in int32_t.
-	 */
-	int32_t Tx, S19, Vos, Vx, fv9, ub, lb;
-
-	Tx = Tdie - 29815;
-	/* S19 is the sensitivity multipled by 1e19 */
-	S19 = S0 * (100000 + 175 * Tx / 100 -
-			1678 * Tx / 100 * Tx / 100000) / 1000;
-	/* Vos is the offset voltage in nV */
-	Vos = -29400 - 570 * Tx / 100 + 463 * Tx / 100 * Tx / 10000;
-	Vx = Vobj - Vos;
-	/* fv9 is Seebeck coefficient f(Vobj) multipled by 1e9 */
-	fv9 = Vx + 134 * Vx / 100000 * Vx / 100000;
-
-	/* The last step in the calculation involves square root, so we use
-	 * binary search.
-	 * Assuming the object temperature is between 200K and 400K, the search
-	 * should take at most 14 iterations.
-	 */
-	ub = 40000;
-	lb = 20000;
-	while (lb != ub) {
-		int32_t t, rhs, lhs;
-
-		t = (ub + lb) / 2;
-		lhs = t / 100 * t / 10000 * t / 10000 * (S19/100) / 1000 * t;
-		rhs = Tdie / 100 * Tdie / 10000 * Tdie / 10000 * (S19/100) /
-			1000 * Tdie + fv9 * 1000;
-		if (lhs > rhs)
-			ub = t;
-		else
-			lb = t + 1;
-	}
-
-	return ub;
+#ifdef CONFIG_TMP006
+	tmp006_poll();
+#endif
+#ifdef CONFIG_PECI
+	peci_temp_sensor_poll();
+#endif
+#ifdef CHIP_lm4
+	chip_temp_sensor_poll();
 #endif
 }
 
-int temp_sensor_tmp006_read_object_temp(const struct temp_sensor_t* sensor)
-{
-	int traw, t;
-	int vraw, v;
-	int rv;
-	int addr = sensor->addr;
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x01, &traw);
-	if (rv)
-		return -1;
-	t = (int)(int16_t)traw / 128 + 273;
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x00, &vraw);
-	if (rv)
-		return -1;
-	v = ((int)(int16_t)vraw * 15625) / 100;
-
-	return temp_sensor_tmp006_calculate_object_temp(t * 100, v, 6400);
-}
-
-void temp_sensor_tmp006_config(const struct temp_sensor_t* sensor)
+void temp_sensor_task(void)
 {
-	int addr = sensor->addr;
-
-	/* Configure the sensor:
-	 * 0x7000 = bits 14:12 = continuous conversion
-	 * 0x0400 = bits 11:9  = ADC conversion rate (1/sec)
-	 * 0x0100 = bit 8      = DRDY pin enabled */
-
-	/* TODO: support shutdown mode for power-saving? */
-	i2c_write16(TMP006_PORT(addr), TMP006_REG(addr), 0x02, 0x7500);
+	while (1) {
+		poll_all_sensors();
+		/* Wait 1s */
+		task_wait_msg(1000000);
+	}
 }
 
-int temp_sensor_tmp006_print(const struct temp_sensor_t* sensor)
-{
-	int vraw, v;
-	int traw, t;
-	int rv;
-	int d;
-	int addr = sensor->addr;
-
-	uart_printf("Debug data from %s:\n", sensor->name);
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0xfe, &d);
-	if (rv)
-		return rv;
-	uart_printf("  Manufacturer ID: 0x%04x\n", d);
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0xff, &d);
-	uart_printf("  Device ID:       0x%04x\n", d);
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x02, &d);
-	uart_printf("  Config:          0x%04x\n", d);
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x00, &vraw);
-	v = ((int)(int16_t)vraw * 15625) / 100;
-	uart_printf("  Voltage:         0x%04x = %d nV\n", vraw, v);
-
-	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x01, &traw);
-	t = ((int)(int16_t)traw * 100) / 128;
-	uart_printf("  Temperature:     0x%04x = %d.%02d C\n",
-		    traw, t / 100, t > 0 ? t % 100 : 100 - (t % 100));
-
-	return EC_SUCCESS;
-}
 /*****************************************************************************/
 /* Console commands */
 
@@ -221,65 +82,6 @@ static int command_temps(int argc, char **argv)
 }
 DECLARE_CONSOLE_COMMAND(temps, command_temps);
 
-static int command_sensor_info(int argc, char **argv)
-{
-	int i;
-	int rv, rv1;
-	const struct temp_sensor_t* sensor;
-
-	rv1 = EC_SUCCESS;
-	for (i = 0; i < TEMP_SENSOR_COUNT; ++i) {
-		sensor = temp_sensors + i;
-		if (sensor->print == TEMP_SENSOR_NO_PRINT)
-			continue;
-		rv = sensor->print(sensor);
-		if (rv != EC_SUCCESS)
-			rv1 = rv;
-	}
-
-	return rv1;
-}
-DECLARE_CONSOLE_COMMAND(tempsinfo, command_sensor_info);
-
-/* TMP006 object temperature calculation command.
- * TODO: This command is only for debugging. Remove it when temporal correciton
- *       is done.
- */
-static int command_sensor_remote(int argc, char **argv)
-{
-	char *e;
-	int32_t Td2, Vobj9, Sm03;
-
-	if (argc != 4) {
-		uart_puts("Usage: tempcorrect <Tdie*100> <Vobj*10^9> <S0*10^11>\n");
-		return EC_ERROR_UNKNOWN;
-	}
-
-	Td2 = strtoi(argv[1], &e, 0);
-	if (e && *e) {
-		uart_puts("Bad Tdie.\n");
-		return EC_ERROR_UNKNOWN;
-	}
-
-	Vobj9 = strtoi(argv[2], &e, 0);
-	if (e && *e) {
-		uart_puts("Bad Vobj.\n");
-		return EC_ERROR_UNKNOWN;
-	}
-
-	Sm03 = strtoi(argv[3], &e, 0);
-	if (e && *e) {
-		uart_puts("Bad S0.\n");
-		return EC_ERROR_UNKNOWN;
-	}
-
-	uart_printf("%d\n",
-		temp_sensor_tmp006_calculate_object_temp(Td2, Vobj9, Sm03));
-
-	return EC_SUCCESS;
-}
-DECLARE_CONSOLE_COMMAND(tempremote, command_sensor_remote);
-
 /*****************************************************************************/
 /* Initialization */
 
diff --git a/common/tmp006.c b/common/tmp006.c
new file mode 100644
index 0000000000..70ad0eb688
--- /dev/null
+++ b/common/tmp006.c
@@ -0,0 +1,253 @@
+/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* TMP006 temperature sensor module for Chrome EC */
+
+#include "tmp006.h"
+#include "temp_sensor.h"
+#include "board.h"
+#include "uart.h"
+#include "util.h"
+#include "console.h"
+#include "task.h"
+#include "fpu.h"
+#include "math.h"
+#include "i2c.h"
+
+/* Defined in board_temp_sensor.c. */
+extern const struct tmp006_t tmp006_sensors[TMP006_COUNT];
+
+struct tmp006_data_t {
+	/* Object voltage */
+	int v;
+	/* The last four die temperature value. Used as a circular buffer. */
+	int t[4];
+	/* The index of the current value in the dir temperature array. */
+	int tidx;
+};
+
+static struct tmp006_data_t tmp006_data[TMP006_COUNT];
+
+static int tmp006_read_die_temp(int idx)
+{
+	int pidx = (tmp006_data[idx].tidx - 1) & 0x3;
+	return tmp006_data[idx].t[pidx] / 100;
+}
+
+/* Calculate the remote object temperature.
+ * Parameters:
+ *     Tdie: Die temperature in 1/100 K.
+ *     Vobj: Voltage read from register 0. In nV.
+ *     S0:   Sensitivity factor in 1e-17.
+ * Return:
+ *     Object temperature in 1/100 K.
+ */
+static int tmp006_calculate_object_temp(int Tdie_i, int Vobj_i, int S0_i)
+{
+	float Tdie, Vobj, S0;
+	float Tx, S, Vos, Vx, fv, Tobj, T4;
+	int Tobj_i;
+
+	enable_fpu();
+
+	Tdie = (float)Tdie_i * 1e-2f;
+	Vobj = (float)Vobj_i * 1e-9f;
+	S0 = (float)S0_i * 1e-17f;
+
+	/* Calculate according to TMP006 users guide. */
+	Tx = Tdie - 298.15f;
+	/* S is the sensitivity */
+	S = S0 * (1.0f + 1.75e-3f * Tx - 1.678e-5f * Tx * Tx);
+	/* Vos is the offset voltage */
+	Vos = -2.94e-5f - 5.7e-7f * Tx + 4.63e-9f * Tx * Tx;
+	Vx = Vobj - Vos;
+	/* fv is Seebeck coefficient f(Vobj) */
+	fv = Vx + 13.4f * Vx * Vx;
+
+	T4 = Tdie * Tdie * Tdie * Tdie + fv / S;
+	Tobj = sqrtf(sqrtf(T4));
+	Tobj_i = (int32_t)(Tobj * 100.0f);
+
+	disable_fpu(Tobj_i);
+
+	return Tobj_i;
+}
+
+/* Temporal Correction
+ * Parameters:
+ *     T1-T4: Four die temperature readings separated by 1s in 1/100K.
+ *     v:     Voltage read from register 0. In nV.
+ * Return:
+ *     Corrected object voltage in 1/100K.
+ */
+static int tmp006_correct_object_voltage(int T1,
+					      int T2,
+					      int T3,
+					      int T4,
+					      int Vobj)
+{
+	int Tslope = 3 * T1 + T2 - T3 - 3 * T4;
+	return Vobj + 296 * Tslope;
+}
+
+static int tmp006_read_object_temp(int idx)
+{
+	int pidx = (tmp006_data[idx].tidx - 1) & 0x3;
+	int t = tmp006_data[idx].t[pidx];
+	int v = tmp006_data[idx].v;
+
+	v = tmp006_correct_object_voltage(
+		t,
+		tmp006_data[idx].t[(pidx + 3) & 3],
+		tmp006_data[idx].t[(pidx + 2) & 3],
+		tmp006_data[idx].t[(pidx + 1) & 3],
+		v);
+
+	/* TODO: Calibrate the sensitivity factor. */
+	return tmp006_calculate_object_temp(t, v, 6400) / 100;
+}
+
+static int tmp006_poll_sensor(int sensor_id)
+{
+	int traw, t;
+	int vraw, v;
+	int rv;
+	int addr = tmp006_sensors[sensor_id].addr;
+	int idx;
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x01, &traw);
+	if (rv)
+		return EC_ERROR_UNKNOWN;
+	t = ((int)(int16_t)traw * 100) / 128 + 27300;
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x00, &vraw);
+	if (rv)
+		return EC_ERROR_UNKNOWN;
+	v = ((int)(int16_t)vraw * 15625) / 100;
+
+	idx = tmp006_data[sensor_id].tidx;
+	tmp006_data[sensor_id].t[idx] = t;
+	tmp006_data[sensor_id].v = v;
+	tmp006_data[sensor_id].tidx = (idx + 1) & 3;
+
+	return EC_SUCCESS;
+}
+
+static int tmp006_print(int idx)
+{
+	int vraw, v;
+	int traw, t;
+	int rv;
+	int d;
+	int addr = tmp006_sensors[idx].addr;
+
+	uart_printf("Debug data from %s:\n", tmp006_sensors[idx].name);
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0xfe, &d);
+	if (rv)
+		return rv;
+	uart_printf("  Manufacturer ID: 0x%04x\n", d);
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0xff, &d);
+	uart_printf("  Device ID:       0x%04x\n", d);
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x02, &d);
+	uart_printf("  Config:          0x%04x\n", d);
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x00, &vraw);
+	v = ((int)(int16_t)vraw * 15625) / 100;
+	uart_printf("  Voltage:         0x%04x = %d nV\n", vraw, v);
+
+	rv = i2c_read16(TMP006_PORT(addr), TMP006_REG(addr), 0x01, &traw);
+	t = ((int)(int16_t)traw * 100) / 128;
+	uart_printf("  Temperature:     0x%04x = %d.%02d C\n",
+		    traw, t / 100, t > 0 ? t % 100 : 100 - (t % 100));
+
+	return EC_SUCCESS;
+}
+
+
+int tmp006_get_val(int idx)
+{
+	/* Check the low bit to determine which temperature to read. */
+	if ((idx & 0x1) == 0)
+		return tmp006_read_die_temp(idx >> 1);
+	else
+		return tmp006_read_object_temp(idx >> 1);
+}
+
+
+int tmp006_poll(void)
+{
+	int i;
+	int rv;
+	int rv1 = EC_SUCCESS;
+
+	for (i = 0; i < TMP006_COUNT; ++i) {
+		rv = tmp006_poll_sensor(i);
+		if (rv != EC_SUCCESS)
+			rv1 = rv;
+	}
+
+	return rv1;
+}
+
+
+/*****************************************************************************/
+/* Console commands */
+
+/* TMP006 object temperature calculation command.
+ * TODO: This command is only for debugging. Remove it when temporal correciton
+ *       is done.
+ */
+static int command_sensor_remote(int argc, char **argv)
+{
+	char *e;
+	int32_t Td2, Vobj9, Sm03;
+
+	if (argc != 4) {
+		uart_puts("Usage: tempcorrect <Tdie*100> <Vobj*10^9> <S0*10^11>\n");
+		return EC_ERROR_UNKNOWN;
+	}
+
+	Td2 = strtoi(argv[1], &e, 0);
+	if (e && *e) {
+		uart_puts("Bad Tdie.\n");
+		return EC_ERROR_UNKNOWN;
+	}
+
+	Vobj9 = strtoi(argv[2], &e, 0);
+	if (e && *e) {
+		uart_puts("Bad Vobj.\n");
+		return EC_ERROR_UNKNOWN;
+	}
+
+	Sm03 = strtoi(argv[3], &e, 0);
+	if (e && *e) {
+		uart_puts("Bad S0.\n");
+		return EC_ERROR_UNKNOWN;
+	}
+
+	uart_printf("%d\n",
+		tmp006_calculate_object_temp(Td2, Vobj9, Sm03));
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(tempremote, command_sensor_remote);
+
+static int command_sensor_info(int argc, char **argv)
+{
+	int i;
+	int rv, rv1;
+
+	rv1 = EC_SUCCESS;
+	for (i = 0; i < TMP006_COUNT; ++i) {
+		rv = tmp006_print(i);
+		if (rv != EC_SUCCESS)
+			rv1 = rv;
+	}
+
+	return rv1;
+}
+DECLARE_CONSOLE_COMMAND(tmp006, command_sensor_info);
diff --git a/include/chip_temp_sensor.h b/include/chip_temp_sensor.h
index 22c358771b..08417cd3d8 100644
--- a/include/chip_temp_sensor.h
+++ b/include/chip_temp_sensor.h
@@ -10,10 +10,11 @@
 
 struct temp_sensor_t;
 
-/* Temperature reading function. Input pointer to a sensor in temp_sensors.
- * Return temperature in K.
- */
-int chip_temp_sensor_read(const struct temp_sensor_t* sensor);
+/* Temperature polling function. */
+int chip_temp_sensor_poll(void);
+
+/* Temperature reading function. Return temperature in K. */
+int chip_temp_sensor_get_val(int idx);
 
 int chip_temp_sensor_init(void);
 
diff --git a/include/peci.h b/include/peci.h
index 11aead9bb1..2b2c33f4a7 100644
--- a/include/peci.h
+++ b/include/peci.h
@@ -24,6 +24,9 @@ int peci_get_cpu_temp(void);
 /* Reads the CPU temperature sensor via PECI.  This interface is for the
  * temperature sensor module.  Returns the temperature in degrees K, or -1 if
  * error. */
-int peci_temp_sensor_read(const struct temp_sensor_t *sensor);
+int peci_temp_sensor_get_val(int idx);
+
+/* Temperature polling of CPU temperature sensor via PECI. */
+int peci_temp_sensor_poll(void);
 
 #endif  /* __CROS_EC_PECI_H */
diff --git a/include/temp_sensor.h b/include/temp_sensor.h
index fb35260e12..b20c77fe88 100644
--- a/include/temp_sensor.h
+++ b/include/temp_sensor.h
@@ -16,24 +16,12 @@ enum temp_sensor_id;
 
 struct temp_sensor_t {
 	const char* name;
-	/* Sensor address. Used by read and print functions. */
-	int addr;
 	/* Read sensor value and return temperature in K. */
-	int (*read)(const struct temp_sensor_t* self);
-	/* Print debug info on console. */
-	int (*print)(const struct temp_sensor_t* self);
+	int (*read)(int idx);
+	/* Index among the same kind of sensors. */
+	int idx;
 };
 
-/* Dummy value to put in "addr" field in temp_sensor_t if we don't need to
- * specify address.
- */
-#define TEMP_SENSOR_NO_ADDR 0
-
-/* Dummy value to put in "print" field in temp_sensor_t if we don't have debug
- * function for a sensor.
- */
-#define TEMP_SENSOR_NO_PRINT 0
-
 /* Initializes the module. */
 int temp_sensor_init(void);
 
@@ -41,21 +29,4 @@ int temp_sensor_init(void);
  * or -1 if error. */
 int temp_sensor_read(enum temp_sensor_id id);
 
-
-#define TMP006_ADDR(PORT,REG) ((PORT << 16) + REG)
-#define TMP006_PORT(ADDR) (ADDR >> 16)
-#define TMP006_REG(ADDR) (ADDR & 0xffff)
-
-/* Read TI TMP006 die temperature sensor. Return temperature in K. */
-int temp_sensor_tmp006_read_die_temp(const struct temp_sensor_t* sensor);
-
-/* Read TI TMP006 object temperature sensor. Return temperature in K. */
-int temp_sensor_tmp006_read_object_temp(const struct temp_sensor_t* sensor);
-
-/* Configure TMP006 DRDY pin. */
-void temp_sensor_tmp006_config(const struct temp_sensor_t* sensor);
-
-/* Print debug messages for TMP006. */
-int temp_sensor_tmp006_print(const struct temp_sensor_t* sensor);
-
 #endif  /* __CROS_EC_TEMP_SENSOR_H */
diff --git a/include/tmp006.h b/include/tmp006.h
new file mode 100644
index 0000000000..1d6e07ffdd
--- /dev/null
+++ b/include/tmp006.h
@@ -0,0 +1,30 @@
+/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* TMP006 temperature sensor module for Chrome EC */
+
+#ifndef __CROS_EC_TMP006_H
+#define __CROS_EC_TMP006_H
+
+#define TMP006_ADDR(PORT,REG) ((PORT << 16) + REG)
+#define TMP006_PORT(ADDR) (ADDR >> 16)
+#define TMP006_REG(ADDR) (ADDR & 0xffff)
+
+struct tmp006_t {
+	const char* name;
+	/* I2C address formed by TMP006_ADDR macro. */
+	int addr;
+};
+
+/* Poll all TMP006 sensors. Return 0 on success. */
+int tmp006_poll(void);
+
+/* Get the last polled value of a sensor. Return temperature in K.
+ * The low bit in idx indicate whether to read die temperature or
+ * object temperature. The other bits serve as internal index to tmp006
+ * module. */
+int tmp006_get_val(int idx);
+
+#endif  /* __CROS_EC_TMP006_H */