linux-kernel - [PATCH 3/5] spi: stm32: move splitting transfers to optimize

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Date: Mon, 12 Feb 2024 17:26:43 -0600
From: David Lechner <dlechner@...libre.com>
To: Mark Brown <broonie@...nel.org>
Cc: David Lechner <dlechner@...libre.com>,
	Martin Sperl <kernel@...tin.sperl.org>,
	David Jander <david@...tonic.nl>,
	Jonathan Cameron <jic23@...nel.org>,
	Michael Hennerich <michael.hennerich@...log.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Alain Volmat <alain.volmat@...s.st.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	linux-spi@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-iio@...r.kernel.org
Subject: [PATCH 3/5] spi: stm32: move splitting transfers to optimize_message

Since splitting transfers was moved to spi_optimize_message() in the
core SPI code, we now need to use the optimize_message callback in the
STM32 SPI driver to ensure that the operation is only performed once
when spi_optimize_message() is used by peripheral drivers explicitly.

Signed-off-by: David Lechner <dlechner@...libre.com>
---
 drivers/spi/spi-stm32.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index c32e57bb38bd..e4e7ddb7524a 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1118,6 +1118,21 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int stm32_spi_optimize_message(struct spi_message *msg)
+{
+	struct spi_controller *ctrl = msg->spi->controller;
+	struct stm32_spi *spi = spi_controller_get_devdata(ctrl);
+
+	/* On STM32H7, messages should not exceed a maximum size set
+	 * later via the set_number_of_data function. In order to
+	 * ensure that, split large messages into several messages
+	 */
+	if (spi->cfg->set_number_of_data)
+		return spi_split_transfers_maxwords(ctrl, msg, spi->t_size_max);
+
+	return 0;
+}
+
 /**
  * stm32_spi_prepare_msg - set up the controller to transfer a single message
  * @ctrl: controller interface
@@ -1163,18 +1178,6 @@ static int stm32_spi_prepare_msg(struct spi_controller *ctrl,
 		!!(spi_dev->mode & SPI_LSB_FIRST),
 		!!(spi_dev->mode & SPI_CS_HIGH));
 
-	/* On STM32H7, messages should not exceed a maximum size setted
-	 * afterward via the set_number_of_data function. In order to
-	 * ensure that, split large messages into several messages
-	 */
-	if (spi->cfg->set_number_of_data) {
-		int ret;
-
-		ret = spi_split_transfers_maxwords(ctrl, msg, spi->t_size_max);
-		if (ret)
-			return ret;
-	}
-
 	spin_lock_irqsave(&spi->lock, flags);
 
 	/* CPOL, CPHA and LSB FIRST bits have common register */
@@ -2180,6 +2183,7 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	ctrl->max_speed_hz = spi->clk_rate / spi->cfg->baud_rate_div_min;
 	ctrl->min_speed_hz = spi->clk_rate / spi->cfg->baud_rate_div_max;
 	ctrl->use_gpio_descriptors = true;
+	ctrl->optimize_message = stm32_spi_optimize_message;
 	ctrl->prepare_message = stm32_spi_prepare_msg;
 	ctrl->transfer_one = stm32_spi_transfer_one;
 	ctrl->unprepare_message = stm32_spi_unprepare_msg;

-- 
2.43.0