3 files changed, 42 insertions, 2 deletions

diff --git a/drivers/thermal/ti-soc-thermal/dra752-thermal-data.c b/drivers/thermal/ti-soc-thermal/dra752-thermal-data.c
index a4929272074f..58b5c6694cd4 100644
--- a/drivers/thermal/ti-soc-thermal/dra752-thermal-data.c
+++ b/drivers/thermal/ti-soc-thermal/dra752-thermal-data.c
@@ -420,7 +420,8 @@ const struct ti_bandgap_data dra752_data = {
                         TI_BANDGAP_FEATURE_FREEZE_BIT |
                         TI_BANDGAP_FEATURE_TALERT |
                         TI_BANDGAP_FEATURE_COUNTER_DELAY |
-                        TI_BANDGAP_FEATURE_HISTORY_BUFFER,
+                        TI_BANDGAP_FEATURE_HISTORY_BUFFER |
+                        TI_BANDGAP_FEATURE_ERRATA_814,
         .fclock_name = "l3instr_ts_gclk_div",
         .div_ck_name = "l3instr_ts_gclk_div",
         .conv_table = dra752_adc_to_temp,
diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
index 62a5d449c388..9747523858a1 100644
--- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
+++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
@@ -119,6 +119,37 @@ exit:
 }
 
 /**
+ * ti_errata814_bandgap_read_temp() - helper function to read dra7 sensor temperature
+ * @bgp: pointer to ti_bandgap structure
+ * @reg: desired register (offset) to be read
+ *
+ * Function to read dra7 bandgap sensor temperature. This is done separately
+ * so as to workaround the errata "Bandgap Temperature read Dtemp can be
+ * corrupted" - Errata ID: i814".
+ * Read accesses to registers listed below can be corrupted due to incorrect
+ * resynchronization between clock domains.
+ * Read access to registers below can be corrupted :
+ * CTRL_CORE_DTEMP_MPU/GPU/CORE/DSPEVE/IVA_n (n = 0 to 4)
+ * CTRL_CORE_TEMP_SENSOR_MPU/GPU/CORE/DSPEVE/IVA_n
+ *
+ * Return: the register value.
+ */
+static u32 ti_errata814_bandgap_read_temp(struct ti_bandgap *bgp,  u32 reg)
+{
+        u32 val1, val2;
+
+        val1 = ti_bandgap_readl(bgp, reg);
+        val2 = ti_bandgap_readl(bgp, reg);
+
+        /* If both times we read the same value then that is right */
+        if (val1 == val2)
+                return val1;
+
+        /* if val1 and val2 are different read it third time */
+        return ti_bandgap_readl(bgp, reg);
+}
+
+/**
  * ti_bandgap_read_temp() - helper function to read sensor temperature
  * @bgp: pointer to ti_bandgap structure
  * @id: bandgap sensor id
@@ -148,7 +179,11 @@ static u32 ti_bandgap_read_temp(struct ti_bandgap *bgp, int id)
         }
 
         /* read temperature */
-        temp = ti_bandgap_readl(bgp, reg);
+        if (TI_BANDGAP_HAS(bgp, ERRATA_814))
+                temp = ti_errata814_bandgap_read_temp(bgp, reg);
+        else
+                temp = ti_bandgap_readl(bgp, reg);
+
         temp &= tsr->bgap_dtemp_mask;
 
         if (TI_BANDGAP_HAS(bgp, FREEZE_BIT))
diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.h b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
index b3adf72f252d..b2da3fc42b51 100644
--- a/drivers/thermal/ti-soc-thermal/ti-bandgap.h
+++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
@@ -318,6 +318,9 @@ struct ti_temp_sensor {
  * TI_BANDGAP_FEATURE_HISTORY_BUFFER - used when the bandgap device features
  *      a history buffer of temperatures.
  *
+ * TI_BANDGAP_FEATURE_ERRATA_814 - used to workaorund when the bandgap device
+ *      has Errata 814
+ *
  * TI_BANDGAP_HAS(b, f) - macro to check if a bandgap device is capable of a
  *      specific feature (above) or not. Return non-zero, if yes.
  */
@@ -331,6 +334,7 @@ struct ti_temp_sensor {
 #define TI_BANDGAP_FEATURE_FREEZE_BIT           BIT(7)
 #define TI_BANDGAP_FEATURE_COUNTER_DELAY        BIT(8)
 #define TI_BANDGAP_FEATURE_HISTORY_BUFFER       BIT(9)
+#define TI_BANDGAP_FEATURE_ERRATA_814           BIT(10)
 #define TI_BANDGAP_HAS(b, f)                    \
                         ((b)->conf->features & TI_BANDGAP_FEATURE_ ## f)