[PATCH v1 13/17] iio: chemical: bme680: Add read buffers in DMA safe region

[Vasileios Amoiridis]

Move the buffers that are used in order to read data from the
device in a DMA-safe region. Also create defines for the number
of bytes that are being read from the device and don't use
magic numbers.

Signed-off-by: Vasileios Amoiridis <vassilisamir@xxxxxxxxx>
---
 drivers/iio/chemical/bme680.h      |  7 ++++++
 drivers/iio/chemical/bme680_core.c | 37 +++++++++++++++---------------
 2 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/chemical/bme680.h b/drivers/iio/chemical/bme680.h
index 5f602170a3af..17ea59253923 100644
--- a/drivers/iio/chemical/bme680.h
+++ b/drivers/iio/chemical/bme680.h
@@ -54,6 +54,13 @@
 #define BME680_REG_MEAS_STAT_0			0x1D
 #define   BME680_GAS_MEAS_BIT			BIT(6)
 
+#define BME680_TEMP_NUM_BYTES			3
+#define BME680_PRESS_NUM_BYTES			3
+#define BME680_HUMID_NUM_BYTES			2
+#define BME680_GAS_NUM_BYTES			2
+
+#define BME680_MEAS_TRIM_MASK			GENMASK(24, 4)
+
 /* Calibration Parameters */
 #define BME680_T2_LSB_REG	0x8A
 #define BME680_H2_MSB_REG	0xE1
diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c
index a6f425076d36..b055eeee8f1c 100644
--- a/drivers/iio/chemical/bme680_core.c
+++ b/drivers/iio/chemical/bme680_core.c
@@ -115,6 +115,9 @@ struct bme680_data {
 	 * transfer buffers to live in their own cache lines.
 	 */
 	union {
+		u8 buf[3];
+		unsigned int check;
+		__be16 be16;
 		u8 bme680_cal_buf_1[BME680_CALIB_RANGE_1_LEN];
 		u8 bme680_cal_buf_2[BME680_CALIB_RANGE_2_LEN];
 		u8 bme680_cal_buf_3[BME680_CALIB_RANGE_3_LEN];
@@ -547,7 +550,6 @@ static int bme680_read_temp(struct bme680_data *data, int *val)
 {
 	struct device *dev = regmap_get_device(data->regmap);
 	int ret;
-	__be32 tmp = 0;
 	u32 adc_temp;
 	s16 comp_temp;
 
@@ -559,13 +561,14 @@ static int bme680_read_temp(struct bme680_data *data, int *val)
 	bme680_wait_for_eoc(data);
 
 	ret = regmap_bulk_read(data->regmap, BME680_REG_TEMP_MSB,
-			       &tmp, 3);
+			       data->buf, BME680_TEMP_NUM_BYTES);
 	if (ret < 0) {
 		dev_err(dev, "failed to read temperature\n");
 		return ret;
 	}
 
-	adc_temp = be32_to_cpu(tmp) >> 12;
+	adc_temp = FIELD_GET(BME680_MEAS_TRIM_MASK,
+			     get_unaligned_be24(data->buf));
 	if (adc_temp == BME680_MEAS_SKIPPED) {
 		/* reading was skipped */
 		dev_err(dev, "reading temperature skipped\n");
@@ -591,7 +594,6 @@ static int bme680_read_press(struct bme680_data *data,
 {
 	struct device *dev = regmap_get_device(data->regmap);
 	int ret;
-	__be32 tmp = 0;
 	u32 adc_press;
 
 	/* Read and compensate temperature to get a reading of t_fine */
@@ -600,13 +602,14 @@ static int bme680_read_press(struct bme680_data *data,
 		return ret;
 
 	ret = regmap_bulk_read(data->regmap, BME680_REG_PRESS_MSB,
-			       &tmp, 3);
+			       data->buf, BME680_PRESS_NUM_BYTES);
 	if (ret < 0) {
 		dev_err(dev, "failed to read pressure\n");
 		return ret;
 	}
 
-	adc_press = be32_to_cpu(tmp) >> 12;
+	adc_press = FIELD_GET(BME680_MEAS_TRIM_MASK,
+			      get_unaligned_be24(data->buf));
 	if (adc_press == BME680_MEAS_SKIPPED) {
 		/* reading was skipped */
 		dev_err(dev, "reading pressure skipped\n");
@@ -623,7 +626,6 @@ static int bme680_read_humid(struct bme680_data *data,
 {
 	struct device *dev = regmap_get_device(data->regmap);
 	int ret;
-	__be16 tmp = 0;
 	u16 adc_humidity;
 	u32 comp_humidity;
 
@@ -633,13 +635,13 @@ static int bme680_read_humid(struct bme680_data *data,
 		return ret;
 
 	ret = regmap_bulk_read(data->regmap, BME680_REG_HUMIDITY_MSB,
-			       &tmp, sizeof(tmp));
+			       &data->be16, BME680_HUMID_NUM_BYTES);
 	if (ret < 0) {
 		dev_err(dev, "failed to read humidity\n");
 		return ret;
 	}
 
-	adc_humidity = be16_to_cpu(tmp);
+	adc_humidity = be16_to_cpu(data->be16);
 	if (adc_humidity == BME680_MEAS_SKIPPED) {
 		/* reading was skipped */
 		dev_err(dev, "reading humidity skipped\n");
@@ -657,8 +659,6 @@ static int bme680_read_gas(struct bme680_data *data,
 {
 	struct device *dev = regmap_get_device(data->regmap);
 	int ret;
-	__be16 tmp = 0;
-	unsigned int check;
 	u16 adc_gas_res, gas_regs_val;
 	u8 gas_range;
 
@@ -676,19 +676,19 @@ static int bme680_read_gas(struct bme680_data *data,
 
 	bme680_wait_for_eoc(data);
 
-	ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &check);
-	if (check & BME680_GAS_MEAS_BIT) {
+	ret = regmap_read(data->regmap, BME680_REG_MEAS_STAT_0, &data->check);
+	if (data->check & BME680_GAS_MEAS_BIT) {
 		dev_err(dev, "gas measurement incomplete\n");
 		return -EBUSY;
 	}
 
 	ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB,
-			       &tmp, sizeof(tmp));
+			       &data->be16, BME680_GAS_NUM_BYTES);
 	if (ret < 0) {
 		dev_err(dev, "failed to read gas resistance\n");
 		return ret;
 	}
-	gas_regs_val = be16_to_cpu(tmp);
+	gas_regs_val = be16_to_cpu(data->be16);
 	adc_gas_res = gas_regs_val >> BME680_ADC_GAS_RES_SHIFT;
 
 	/*
@@ -817,7 +817,6 @@ int bme680_core_probe(struct device *dev, struct regmap *regmap,
 {
 	struct iio_dev *indio_dev;
 	struct bme680_data *data;
-	unsigned int val;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
@@ -848,15 +847,15 @@ int bme680_core_probe(struct device *dev, struct regmap *regmap,
 		return ret;
 	}
 
-	ret = regmap_read(regmap, BME680_REG_CHIP_ID, &val);
+	ret = regmap_read(regmap, BME680_REG_CHIP_ID, &data->check);
 	if (ret < 0) {
 		dev_err(dev, "Error reading chip ID\n");
 		return ret;
 	}
 
-	if (val != BME680_CHIP_ID_VAL) {
+	if (data->check != BME680_CHIP_ID_VAL) {
 		dev_err(dev, "Wrong chip ID, got %x expected %x\n",
-			val, BME680_CHIP_ID_VAL);
+			data->check, BME680_CHIP_ID_VAL);
 		return -ENODEV;
 	}
 
-- 
2.25.1