[PATCH v13 5/9] drivers: thermal: tsens: Fix bug in sensor enable for msm8960

From: Ansuel Smith
Date: Wed Mar 24 2021 - 17:45:08 EST


Device based on tsens VER_0 contains a hardware bug that results in some
problem with sensor enablement. Sensor id 6-11 can't be enabled
selectively and all of them must be enabled in one step.

Signed-off-by: Ansuel Smith <ansuelsmth@xxxxxxxxx>
Acked-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
---
drivers/thermal/qcom/tsens-8960.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/qcom/tsens-8960.c b/drivers/thermal/qcom/tsens-8960.c
index 86585f439985..95fcccafae14 100644
--- a/drivers/thermal/qcom/tsens-8960.c
+++ b/drivers/thermal/qcom/tsens-8960.c
@@ -27,9 +27,9 @@
#define EN BIT(0)
#define SW_RST BIT(1)
#define SENSOR0_EN BIT(3)
+#define MEASURE_PERIOD BIT(18)
#define SLP_CLK_ENA BIT(26)
#define SLP_CLK_ENA_8660 BIT(24)
-#define MEASURE_PERIOD 1
#define SENSOR0_SHIFT 3

/* INT_STATUS_ADDR bitmasks */
@@ -126,17 +126,34 @@ static int resume_8960(struct tsens_priv *priv)
static int enable_8960(struct tsens_priv *priv, int id)
{
int ret;
- u32 reg, mask;
+ u32 reg, mask = BIT(id);

ret = regmap_read(priv->tm_map, CNTL_ADDR, &reg);
if (ret)
return ret;

- mask = BIT(id + SENSOR0_SHIFT);
+ /* HARDWARE BUG:
+ * On platforms with more than 6 sensors, all remaining sensors
+ * must be enabled together, otherwise undefined results are expected.
+ * (Sensor 6-7 disabled, Sensor 3 disabled...) In the original driver,
+ * all the sensors are enabled in one step hence this bug is not
+ * triggered.
+ */
+ if (id > 5)
+ mask = GENMASK(10, 6);
+
+ mask <<= SENSOR0_SHIFT;
+
+ /* Sensors already enabled. Skip. */
+ if ((reg & mask) == mask)
+ return 0;
+
ret = regmap_write(priv->tm_map, CNTL_ADDR, reg | SW_RST);
if (ret)
return ret;

+ reg |= MEASURE_PERIOD;
+
if (priv->num_sensors > 1)
reg |= mask | SLP_CLK_ENA | EN;
else
--
2.30.2