iio: light: stk3310: Deal with the ps interrupt issue in PM

On the Inspur HS326 laptop(which integrated with HiSilicon M900
processor), if the STK3311-X chip's PS interrupt is configured
in "Recommended interrupt mode", the interrupt cannot be triggered
normally after waking from suspend or hibernation.

In this case, neither disabling and re-enabling the interrupt nor
resetting the PS threshold register can restore the interrupt to
normal operation.

If the interrupt is disabled in suspend() then reset the PS threshold
register and enable the interrupt in resume(). This resolves the issue.

Signed-off-by: Miao Li <limiao@kylinos.cn>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: Miao Li

drivers/iio/light/stk3310.c

@@ -130,6 +130,9 @@ struct stk3310_data {
 	struct mutex lock;
 	bool als_enabled;
 	bool ps_enabled;
+	bool ps_int_enabled;
+	uint32_t ps_thdl;
+	uint32_t ps_thdh;
 	uint32_t ps_near_level;
 	u64 timestamp;
 	struct regmap *regmap;
@@ -309,10 +312,17 @@ static int stk3310_write_event(struct iio_dev *indio_dev,
 
 	buf = cpu_to_be16(val);
 	ret = regmap_bulk_write(data->regmap, reg, &buf, 2);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(&client->dev, "failed to set PS threshold!\n");
+		return ret;
+	}
 
-	return ret;
+	if (reg == STK3310_REG_THDH_PS)
+		data->ps_thdh = val;
+	else
+		data->ps_thdl = val;
+
+	return 0;
 }
 
 static int stk3310_read_event_config(struct iio_dev *indio_dev,
@@ -344,11 +354,17 @@ static int stk3310_write_event_config(struct iio_dev *indio_dev,
 	/* Set INT_PS value */
 	mutex_lock(&data->lock);
 	ret = regmap_field_write(data->reg_int_ps, state);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(&client->dev, "failed to set interrupt mode\n");
+		mutex_unlock(&data->lock);
+		return ret;
+	}
+
+	data->ps_int_enabled = state;
+
 	mutex_unlock(&data->lock);
 
-	return ret;
+	return 0;
 }
 
 static int stk3310_read_raw(struct iio_dev *indio_dev,
@@ -517,10 +533,15 @@ static int stk3310_init(struct iio_dev *indio_dev)
 
 	/* Enable PS interrupts */
 	ret = regmap_field_write(data->reg_int_ps, STK3310_PSINT_EN);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(&client->dev, "failed to enable interrupts!\n");
+		return ret;
+	}
 
-	return ret;
+	data->ps_int_enabled = true;
+	data->ps_thdh = STK3310_PS_MAX_VAL;
+
+	return 0;
 }
 
 static bool stk3310_is_volatile_reg(struct device *dev, unsigned int reg)
@@ -684,24 +705,65 @@ static void stk3310_remove(struct i2c_client *client)
 static int stk3310_suspend(struct device *dev)
 {
 	struct stk3310_data *data;
+	int ret;
 
 	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 
+	if (data->ps_int_enabled) {
+		ret = regmap_field_write(data->reg_int_ps, 0x0);
+		if (ret < 0) {
+			dev_err(dev, "failed to disable ps int at suspend.\n");
+			return ret;
+		}
+	}
+
 	return stk3310_set_state(data, STK3310_STATE_STANDBY);
 }
 
 static int stk3310_resume(struct device *dev)
 {
 	u8 state = 0;
 	struct stk3310_data *data;
+	__be16 buf;
+	int ret;
 
 	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 	if (data->ps_enabled)
 		state |= STK3310_STATE_EN_PS;
 	if (data->als_enabled)
 		state |= STK3310_STATE_EN_ALS;
 
-	return stk3310_set_state(data, state);
+	ret = stk3310_set_state(data, state);
+	if (ret < 0)
+		return ret;
+
+	if (data->ps_thdl != 0x0) {
+		buf = cpu_to_be16(data->ps_thdl);
+		ret = regmap_bulk_write(data->regmap, STK3310_REG_THDL_PS, &buf, 2);
+		if (ret < 0) {
+			dev_err(dev, "failed to set reg THDL_PS at resume.\n");
+			return ret;
+		}
+	}
+
+	if (data->ps_thdh != STK3310_PS_MAX_VAL) {
+		buf = cpu_to_be16(data->ps_thdh);
+		ret = regmap_bulk_write(data->regmap, STK3310_REG_THDH_PS, &buf, 2);
+		if (ret < 0) {
+			dev_err(dev, "failed to set reg THDH_PS at resume.\n");
+			return ret;
+		}
+	}
+
+	if (data->ps_int_enabled) {
+		ret = regmap_field_write(data->reg_int_ps, STK3310_PSINT_EN);
+		if (ret < 0) {
+			dev_err(dev, "failed to enable ps int at resume.\n");
+			return ret;
+		}
+	}
+
+	return 0;
 }
 
 static DEFINE_SIMPLE_DEV_PM_OPS(stk3310_pm_ops, stk3310_suspend,