iio: qcom-tadc: use HW default for batt therm HW conversion trigger

The battery thermistor channel is unused in parallel charge applications
since the primary charger disables the parallel charger when hard JEITA
limits are reached.

In standalone applications the battery thermistor channel is used since
it is required for JEITA.

The hardware defaults take care of both of these applications hence
mask the register writes to enable only the die temperature, and
connector thermistor hardware conversion triggers. This will ensure the
battery thermistor hardware conversion trigger is left to the hardware
default.

Change-Id: Iea2fc779562436dfae3bd41c944d5727366006b2
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>

1 files changed, 42 insertions, 7 deletions

diff --git a/drivers/iio/adc/qcom-tadc.c b/drivers/iio/adc/qcom-tadc.c
index 054dfcc8556a..05b1985ba378 100644
--- a/drivers/iio/adc/qcom-tadc.c
+++ b/drivers/iio/adc/qcom-tadc.c
@@ -228,6 +228,7 @@ struct tadc_chip {
 	struct votable		*tadc_disable_votable;
 	struct work_struct	status_change_work;
 	struct notifier_block	nb;
+	u8			hwtrig_conv;
 };
 
 struct tadc_pt {
@@ -356,6 +357,26 @@ unlock:
 	return rc;
 }
 
+static int tadc_masked_write(struct tadc_chip *chip, u16 reg, u8 mask, u8 data)
+{
+	int rc = 0;
+
+	mutex_lock(&chip->write_lock);
+	if (tadc_is_reg_locked(chip, reg)) {
+		rc = regmap_write(chip->regmap, (reg & 0xFF00) | 0xD0, 0xA5);
+		if (rc < 0) {
+			pr_err("Couldn't unlock secure register rc=%d\n", rc);
+			goto unlock;
+		}
+	}
+
+	rc = regmap_update_bits(chip->regmap, reg, mask, data);
+
+unlock:
+	mutex_unlock(&chip->write_lock);
+	return rc;
+}
+
 static int tadc_lerp(const struct tadc_pt *pts, size_t size, bool inv,
 							s32 input, s32 *output)
 {
@@ -880,6 +901,12 @@ static int tadc_disable_vote_callback(struct votable *votable,
 		if (timeleft == 0)
 			pr_err("Timed out waiting for eoc, disabling hw conversions regardless\n");
 
+		rc = tadc_read(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip),
+							&chip->hwtrig_conv, 1);
+		if (rc < 0) {
+			pr_err("Couldn't save hw conversions rc=%d\n", rc);
+			return rc;
+		}
 		rc = tadc_write(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip), 0x00);
 		if (rc < 0) {
 			pr_err("Couldn't disable hw conversions rc=%d\n", rc);
@@ -896,9 +923,10 @@ static int tadc_disable_vote_callback(struct votable *votable,
 			pr_err("Couldn't disable direct test mode rc=%d\n", rc);
 			return rc;
 		}
-		rc = tadc_write(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip), 0x07);
+		rc = tadc_write(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip),
+							chip->hwtrig_conv);
 		if (rc < 0) {
-			pr_err("Couldn't enable hw conversions rc=%d\n", rc);
+			pr_err("Couldn't restore hw conversions rc=%d\n", rc);
 			return rc;
 		}
 	}
@@ -1126,16 +1154,23 @@ static int tadc_init_hw(struct tadc_chip *chip)
 		return rc;
 	}
 
-	/* enable all temperature hardware triggers */
-	rc = tadc_write(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip),
-							BIT(TADC_THERM1) |
-							BIT(TADC_THERM2) |
-							BIT(TADC_DIE_TEMP));
+	/* enable connector and die temp hardware triggers */
+	rc = tadc_masked_write(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip),
+					BIT(TADC_THERM2) | BIT(TADC_DIE_TEMP),
+					BIT(TADC_THERM2) | BIT(TADC_DIE_TEMP));
 	if (rc < 0) {
 		pr_err("Couldn't enable hardware triggers rc=%d\n", rc);
 		return rc;
 	}
 
+	/* save hw triggered conversion configuration */
+	rc = tadc_read(chip, TADC_HWTRIG_CONV_CH_EN_REG(chip),
+							&chip->hwtrig_conv, 1);
+	if (rc < 0) {
+		pr_err("Couldn't save hw conversions rc=%d\n", rc);
+		return rc;
+	}
+
 	return 0;
 }