linux-kernel - [PATCH 5/8] iio: adc: ad7476: Conditionally call convstart

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Message-ID: <2030974bcd7a6fd0a904ae8dc9e9872086c59886.1754463393.git.mazziesaccount@gmail.com>
Date: Wed, 6 Aug 2025 10:04:00 +0300
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Matti Vaittinen <mazziesaccount@...il.com>,
	Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc: Lars-Peter Clausen <lars@...afoo.de>,
	Michael Hennerich <Michael.Hennerich@...log.com>,
	Jonathan Cameron <jic23@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	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>,
	Matti Vaittinen <mazziesaccount@...il.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 5/8] iio: adc: ad7476: Conditionally call convstart

The ad7476 supports two IC variants which may have a 'convstart' -GPIO
for starting the conversion. Currently the driver calls a function which
tries to access the GPIO for all of the IC variants, whether they
support 'convstart' or not. This is not an error because this function
returns early if GPIO information is not populated.

We can do a tad better by calling this function only for the ICs which
have the 'convstart' by providing a function pointer to the convstart
function from the chip_info structure, and calling this function only
for the ICs which have the function pointer set.

This does also allow to support ICs which require different convstart
handling than the currently supported ICs.

Call convstart function only on the ICs which can support it and allow
IC-specific convstart functions for the ICs which require different
handling.

Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
---
The follow-up patch adding support for the ROHM BD79105 will bring
different 'convstart' functions in use. The IC specific pointer will
also prepare the way for this.
---
 drivers/iio/adc/ad7476.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c
index fc701267358e..1f736be09663 100644
--- a/drivers/iio/adc/ad7476.c
+++ b/drivers/iio/adc/ad7476.c
@@ -32,6 +32,7 @@ struct ad7476_chip_info {
 	/* channels used when convst gpio is defined */
 	struct iio_chan_spec		convst_channel[2];
 	void (*reset)(struct ad7476_state *);
+	void (*conversion_pre_op)(struct ad7476_state *st);
 	bool				has_vref;
 	bool				has_vdrive;
 };
@@ -70,7 +71,8 @@ static irqreturn_t ad7476_trigger_handler(int irq, void  *p)
 	struct ad7476_state *st = iio_priv(indio_dev);
 	int b_sent;
 
-	ad7091_convst(st);
+	if (st->chip_info->conversion_pre_op)
+		st->chip_info->conversion_pre_op(st);
 
 	b_sent = spi_sync(st->spi, &st->msg);
 	if (b_sent < 0)
@@ -164,6 +166,7 @@ static const struct ad7476_chip_info ad7091_chip_info = {
 	.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 	.convst_channel[0] = AD7091R_CONVST_CHAN(12),
 	.convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
+	.conversion_pre_op = ad7091_convst,
 	.reset = ad7091_reset,
 };
 
@@ -172,6 +175,7 @@ static const struct ad7476_chip_info ad7091r_chip_info = {
 	.channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
 	.convst_channel[0] = AD7091R_CONVST_CHAN(12),
 	.convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
+	.conversion_pre_op = ad7091_convst,
 	.int_vref_mv = 2500,
 	.has_vref = true,
 	.reset = ad7091_reset,
-- 
2.50.1


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