linux-kernel - [PATCH v2 1/4] iio: adc: dln2-adc: zero full struct instead of just the padding

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Message-ID: <20241214191421.94172-2-vassilisamir@gmail.com>
Date: Sat, 14 Dec 2024 20:14:18 +0100
From: Vasileios Amoiridis <vassilisamir@...il.com>
To: jic23@...nel.org,
	lars@...afoo.de
Cc: krzysztof.kozlowski@...aro.org,
	nuno.sa@...log.com,
	u.kleine-koenig@...libre.com,
	abhashkumarjha123@...il.com,
	jstephan@...libre.com,
	dlechner@...libre.com,
	jackoalan@...il.com,
	k.wrona@...sung.com,
	linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	vassilisamir@...il.com
Subject: [PATCH v2 1/4] iio: adc: dln2-adc: zero full struct instead of just the padding

Drop a minor optimization of zeroing the padding between data and
timestamp and zero the whole structure. This is done in favor of
simpler code, and in order to drop the usage of the internal private
variable "scan_timestamp" of the struct iio_dev.

Signed-off-by: Vasileios Amoiridis <vassilisamir@...il.com>
---
 drivers/iio/adc/dln2-adc.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/adc/dln2-adc.c b/drivers/iio/adc/dln2-adc.c
index 30328626d9be..221a5fdc1eaa 100644
--- a/drivers/iio/adc/dln2-adc.c
+++ b/drivers/iio/adc/dln2-adc.c
@@ -66,8 +66,6 @@ struct dln2_adc {
 	/* Demux table */
 	unsigned int demux_count;
 	struct dln2_adc_demux_table demux[DLN2_ADC_MAX_CHANNELS];
-	/* Precomputed timestamp padding offset and length */
-	unsigned int ts_pad_offset, ts_pad_length;
 };
 
 struct dln2_adc_port_chan {
@@ -111,8 +109,6 @@ static void dln2_adc_update_demux(struct dln2_adc *dln2)
 	if (iio_get_masklength(indio_dev) &&
 	    (*indio_dev->active_scan_mask & 0xff) == 0xff) {
 		dln2_adc_add_demux(dln2, 0, 0, 16);
-		dln2->ts_pad_offset = 0;
-		dln2->ts_pad_length = 0;
 		return;
 	}
 
@@ -127,16 +123,6 @@ static void dln2_adc_update_demux(struct dln2_adc *dln2)
 		out_loc += 2;
 		in_loc += 2;
 	}
-
-	if (indio_dev->scan_timestamp) {
-		size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
-
-		dln2->ts_pad_offset = out_loc;
-		dln2->ts_pad_length = ts_offset * sizeof(int64_t) - out_loc;
-	} else {
-		dln2->ts_pad_offset = 0;
-		dln2->ts_pad_length = 0;
-	}
 }
 
 static int dln2_adc_get_chan_count(struct dln2_adc *dln2)
@@ -494,6 +480,8 @@ static irqreturn_t dln2_adc_trigger_h(int irq, void *p)
 	if (ret < 0)
 		goto done;
 
+	memset(&data, 0, sizeof(data));
+
 	/* Demux operation */
 	for (i = 0; i < dln2->demux_count; ++i) {
 		t = &dln2->demux[i];
@@ -501,11 +489,6 @@ static irqreturn_t dln2_adc_trigger_h(int irq, void *p)
 		       (void *)dev_data.values + t->from, t->length);
 	}
 
-	/* Zero padding space between values and timestamp */
-	if (dln2->ts_pad_length)
-		memset((void *)data.values + dln2->ts_pad_offset,
-		       0, dln2->ts_pad_length);
-
 	iio_push_to_buffers_with_timestamp(indio_dev, &data,
 					   iio_get_time_ns(indio_dev));
 
-- 
2.43.0