From: Ben Cahill <ben.m.cahill@xxxxxxxxx>
Document temperature calculation
Signed-off-by: Ben Cahill <ben.m.cahill@xxxxxxxxx>
Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx>
---
drivers/net/wireless/iwlwifi/iwl-4965-hw.h | 57 ++++++++++++++++++++++-----
1 files changed, 46 insertions(+), 11 deletions(-)
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
index 6f91c02..d47179e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-hw.h
@@ -645,21 +645,43 @@ static inline int iwl4965_hw_valid_rtc_data_addr(u32 addr)
(addr < KDR_RTC_DATA_UPPER_BOUND);
}
-/********************* START TXPOWER *****************************************/
-
-enum {
- CALIB_CH_GROUP_1 = 0,
- CALIB_CH_GROUP_2 = 1,
- CALIB_CH_GROUP_3 = 2,
- CALIB_CH_GROUP_4 = 3,
- CALIB_CH_GROUP_5 = 4,
- CALIB_CH_GROUP_MAX
-};
+/********************* START TEMPERATURE *************************************/
-/* Temperature calibration offset is 3% 0C in Kelvin */
+/*
+ * 4965 temperature calculation.
+ *
+ * The driver must calculate the device temperature before calculating
+ * a txpower setting (amplifier gain is temperature dependent). The
+ * calculation uses 4 measurements, 3 of which (R1, R2, R3) are calibration
+ * values used for the life of the driver, and one of which (R4) is the
+ * real-time temperature indicator.
+ *
+ * uCode provides all 4 values to the driver via the "initialize alive"
+ * notification (see struct iwl4965_init_alive_resp). After the runtime uCode
+ * image loads, uCode updates the R4 value via statistics notifications
+ * (see STATISTICS_NOTIFICATION), which occur after each received beacon
+ * when associated, or can be requested via REPLY_STATISTICS_CMD.
+ *
+ * NOTE: uCode provides the R4 value as a 23-bit signed value. Driver
+ * must sign-extend to 32 bits before applying formula below.
+ *
+ * Formula:
+ *
+ * degrees Kelvin = ((97 * 259 * (R4 - R2) / (R3 - R1)) / 100) + 8
+ *
+ * NOTE: The basic formula is 259 * (R4-R2) / (R3-R1). The 97/100 is
+ * an additional correction, which should be centered around 0 degrees
+ * Celsius (273 degrees Kelvin). The 8 (3 percent of 273) compensates for
+ * centering the 97/100 correction around 0 degrees K.
+ *
+ * Add 273 to Kelvin value to find degrees Celsius, for comparing current
+ * temperature with factory-measured temperatures when calculating txpower
+ * settings.
+ */
#define TEMPERATURE_CALIB_KELVIN_OFFSET 8
#define TEMPERATURE_CALIB_A_VAL 259
+/* Limit range of calculated temperature to be between these Kelvin values */
#define IWL_TX_POWER_TEMPERATURE_MIN (263)
#define IWL_TX_POWER_TEMPERATURE_MAX (410)
@@ -667,6 +689,19 @@ enum {
(((t) < IWL_TX_POWER_TEMPERATURE_MIN) || \
((t) > IWL_TX_POWER_TEMPERATURE_MAX))
+/********************* END TEMPERATURE ***************************************/
+
+/********************* START TXPOWER *****************************************/
+
+enum {
+ CALIB_CH_GROUP_1 = 0,
+ CALIB_CH_GROUP_2 = 1,
+ CALIB_CH_GROUP_3 = 2,
+ CALIB_CH_GROUP_4 = 3,
+ CALIB_CH_GROUP_5 = 4,
+ CALIB_CH_GROUP_MAX
+};
+
#define IWL_TX_POWER_MIMO_REGULATORY_COMPENSATION (6)
#define IWL_TX_POWER_TARGET_POWER_MIN (0) /* 0 dBm = 1 milliwatt */
--
1.5.3.6
-
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