linux-kernel - [PATCH v1 10/17] iio: chemical: bme680: Remove duplicate register read

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Date: Mon, 27 May 2024 20:37:58 +0200
From: Vasileios Amoiridis <vassilisamir@...il.com>
To: jic23@...nel.org,
	lars@...afoo.de
Cc: himanshujha199640@...il.com,
	linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Vasileios Amoiridis <vassilisamir@...il.com>
Subject: [PATCH v1 10/17] iio: chemical: bme680: Remove duplicate register read

The LSB of the gas register was read first to check if the following
check was correct and then the MSB+LSB were read together. Simplify
this by reading together the MSB+LSB immediately.

Signed-off-by: Vasileios Amoiridis <vassilisamir@...il.com>
---
 drivers/iio/chemical/bme680_core.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c
index 96423861c79a..681f271f9b06 100644
--- a/drivers/iio/chemical/bme680_core.c
+++ b/drivers/iio/chemical/bme680_core.c
@@ -748,7 +748,7 @@ static int bme680_read_gas(struct bme680_data *data,
 	int ret;
 	__be16 tmp = 0;
 	unsigned int check;
-	u16 adc_gas_res;
+	u16 adc_gas_res, gas_regs_val;
 	u8 gas_range;
 
 	/* Set heater settings */
@@ -771,11 +771,14 @@ static int bme680_read_gas(struct bme680_data *data,
 		return -EBUSY;
 	}
 
-	ret = regmap_read(data->regmap, BME680_REG_GAS_R_LSB, &check);
+	ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB,
+			       &tmp, sizeof(tmp));
 	if (ret < 0) {
-		dev_err(dev, "failed to read gas_r_lsb register\n");
+		dev_err(dev, "failed to read gas resistance\n");
 		return ret;
 	}
+	gas_regs_val = be16_to_cpu(tmp);
+	adc_gas_res = gas_regs_val >> BME680_ADC_GAS_RES_SHIFT;
 
 	/*
 	 * occurs if either the gas heating duration was insuffient
@@ -783,20 +786,12 @@ static int bme680_read_gas(struct bme680_data *data,
 	 * heater temperature was too high for the heater sink to
 	 * reach.
 	 */
-	if ((check & BME680_GAS_STAB_BIT) == 0) {
+	if ((gas_regs_val & BME680_GAS_STAB_BIT) == 0) {
 		dev_err(dev, "heater failed to reach the target temperature\n");
 		return -EINVAL;
 	}
 
-	ret = regmap_bulk_read(data->regmap, BME680_REG_GAS_MSB,
-			       &tmp, sizeof(tmp));
-	if (ret < 0) {
-		dev_err(dev, "failed to read gas resistance\n");
-		return ret;
-	}
-
-	gas_range = check & BME680_GAS_RANGE_MASK;
-	adc_gas_res = be16_to_cpu(tmp) >> BME680_ADC_GAS_RES_SHIFT;
+	gas_range = gas_regs_val & BME680_GAS_RANGE_MASK;
 
 	*val = bme680_compensate_gas(data, adc_gas_res, gas_range);
 	return IIO_VAL_INT;
-- 
2.25.1