linux-kernel - [PATCH v3 05/12] iio: adc: ad_sigma_delta: use BITS_TO

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Message-Id: <20250701-iio-adc-ad7173-add-spi-offload-support-v3-5-42abb83e3dac@baylibre.com>
Date: Tue, 01 Jul 2025 16:37:53 -0500
From: David Lechner <dlechner@...libre.com>
To: Michael Hennerich <Michael.Hennerich@...log.com>, 
 Jonathan Cameron <jic23@...nel.org>, 
 Nuno Sá <nuno.sa@...log.com>, 
 Andy Shevchenko <andy@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Mark Brown <broonie@...nel.org>
Cc: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-spi@...r.kernel.org, 
 David Lechner <dlechner@...libre.com>
Subject: [PATCH v3 05/12] iio: adc: ad_sigma_delta: use BITS_TO_BYTES()
 macro

Use the BITS_TO_BYTES() macro instead of dividing by 8 to convert bits
to bytes.

This makes it more obvious what unit conversion is taking place.

In one instance, we also avoid the temporary assignment to a variable
as it was confusing that reg_size was being used with two different
units (bits and bytes).

scan_type is factored out to reduce line wrapping.

Signed-off-by: David Lechner <dlechner@...libre.com>
---
 drivers/iio/adc/ad_sigma_delta.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index dd15c357d1494bf5718e50e50a514cb4d4556f2b..f91f7ae6dfca05cf3ae632a5f19990f3d153b706 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/align.h>
+#include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
@@ -190,7 +191,7 @@ int ad_sd_reset(struct ad_sigma_delta *sigma_delta)
 	u8 *buf;
 	int ret;
 
-	size = DIV_ROUND_UP(reset_length, 8);
+	size = BITS_TO_BYTES(reset_length);
 	buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -419,7 +420,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
 		data_reg = AD_SD_REG_DATA;
 
 	ret = ad_sd_read_reg(sigma_delta, data_reg,
-		DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
+		BITS_TO_BYTES(chan->scan_type.realbits + chan->scan_type.shift),
 		&raw_sample);
 
 out:
@@ -453,6 +454,7 @@ EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, "IIO_AD_SIGMA_DELTA");
 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
+	const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type;
 	unsigned int i, slot, samples_buf_size;
 	unsigned int channel;
 	u8 *samples_buf;
@@ -488,7 +490,7 @@ static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
 			return ret;
 	}
 
-	samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits / 8,
+	samples_buf_size = ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits),
 				 sizeof(s64));
 	samples_buf_size += sizeof(s64);
 	samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf,
@@ -544,6 +546,7 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
+	const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type;
 	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
 	u8 *data = sigma_delta->rx_buf;
 	unsigned int transfer_size;
@@ -553,9 +556,7 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
 	unsigned int reg_size;
 	unsigned int data_reg;
 
-	reg_size = indio_dev->channels[0].scan_type.realbits +
-			indio_dev->channels[0].scan_type.shift;
-	reg_size = DIV_ROUND_UP(reg_size, 8);
+	reg_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift);
 
 	if (sigma_delta->info->data_reg != 0)
 		data_reg = sigma_delta->info->data_reg;
@@ -617,7 +618,7 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
 		}
 	}
 
-	sample_size = indio_dev->channels[0].scan_type.storagebits / 8;
+	sample_size = BITS_TO_BYTES(scan_type->storagebits);
 	sample_pos = sample_size * sigma_delta->current_slot;
 	memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
 	sigma_delta->current_slot++;

-- 
2.43.0