Re: [PATCH 3/3] thermal/drivers/tsens: Extract and shift-in optional MSB

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On 06/04/2023 17:58, Bryan O'Donoghue wrote:
In msm8939 some of the sensor calibration data traverses byte boundaries.
Two examples of this are thermal sensor 2 point 1 and sensor 9 point 2.

For sensor 2 point 1 we can get away with a simple read traversing byte
boundaries as the calibration most significant bits are adjacent to the
least significant across the byte boundary.

In this case a read starting at the end of the first byte for nine bits
will deliver up the data we want.

In the case of sensor 9 point 2 however, the most significant bits are not
adjacent and so therefore we need to perform two reads and or the bits
together.

If reg.p1_shift or reg.p2_shift is set then automatically search for
pX_sY_msb in the dts applying pX_shift as a right shift or into the pX_sY
value.

I think that having this in the common code is a bit of an overkill. No other platform has this 'peculiarity' up to now. So, it might be better to add 8939-specific calibration function that calls tsens_read_calibration(), mixes in the s10_p2_msb and then calls compute_intercept_slope().


Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
  drivers/thermal/qcom/tsens.c | 33 +++++++++++++++++++++++++++++++++
  1 file changed, 33 insertions(+)

diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
index a260f563b4889..eff2c8671c343 100644
--- a/drivers/thermal/qcom/tsens.c
+++ b/drivers/thermal/qcom/tsens.c
@@ -74,6 +74,7 @@ int tsens_read_calibration(struct tsens_priv *priv, int shift, u32 *p1, u32 *p2,
  {
  	u32 mode;
  	u32 base1, base2;
+	u32 msb;
  	char name[] = "sXX_pY_backup"; /* s10_p1_backup */
  	int i, ret;
@@ -122,6 +123,22 @@ int tsens_read_calibration(struct tsens_priv *priv, int shift, u32 *p1, u32 *p2, dev_dbg(priv->dev, "%s 0x%x\n", name, p1[i]); + if (priv->reg && priv->reg[i].p1_shift) {
+			ret = snprintf(name, sizeof(name), "s%d_p1_msb",
+				       priv->sensor[i].hw_id);
+			if (ret < 0)
+				return ret;
+
+			ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &msb);
+			if (ret) {
+				dev_err(priv->dev, "Failed to read %s\n", name);
+				return ret;
+			}
+
+			dev_dbg(priv->dev, "%s 0x%x\n", name, msb);
+			p1[i] |= msb >> priv->reg[i].p1_shift;
+		}
+
  		ret = snprintf(name, sizeof(name), "s%d_p2%s", priv->sensor[i].hw_id,
  			       backup ? "_backup" : "");
  		if (ret < 0)
@@ -134,6 +151,22 @@ int tsens_read_calibration(struct tsens_priv *priv, int shift, u32 *p1, u32 *p2,
  		}
dev_dbg(priv->dev, "%s 0x%x\n", name, p2[i]);
+
+		if (priv->reg && priv->reg[i].p2_shift) {
+			ret = snprintf(name, sizeof(name), "s%d_p2_msb",
+				       priv->sensor[i].hw_id);
+			if (ret < 0)
+				return ret;
+
+			ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &msb);
+			if (ret) {
+				dev_err(priv->dev, "Failed to read %s\n", name);
+				return ret;
+			}
+
+			dev_dbg(priv->dev, "%s 0x%x\n", name, msb);
+			p2[i] |= msb >> priv->reg[i].p2_shift;
+		}
  	}
switch (mode) {

--
With best wishes
Dmitry




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