linux-kernel - [PATCH v2] spi: stm32: disable device mode with st,stm32f4-spi compatible

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Message-ID: <20230627123906.147029-1-valentin.caron@foss.st.com>
Date:   Tue, 27 Jun 2023 14:39:06 +0200
From:   Valentin Caron <valentin.caron@...s.st.com>
To:     Mark Brown <broonie@...nel.org>
CC:     Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Alain Volmat <alain.volmat@...s.st.com>,
        <linux-spi@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Valentin Caron <valentin.caron@...s.st.com>
Subject: [PATCH v2] spi: stm32: disable device mode with st,stm32f4-spi compatible

STM32 SPI driver is not capable to handle device mode with stm32f4 soc.
Stop probing if this case happens, and print an error with involved
compatible.

Signed-off-by: Valentin Caron <valentin.caron@...s.st.com>
---
Changes since v1:
- Replace of_match_device()->data by of_device_get_match_data()

 drivers/spi/spi-stm32.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 6d10fa4ab783..0de56441f72e 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -238,6 +238,7 @@ struct stm32_spi;
  * @baud_rate_div_min: minimum baud rate divisor
  * @baud_rate_div_max: maximum baud rate divisor
  * @has_fifo: boolean to know if fifo is used for driver
+ * @has_device_mode: is this compatible capable to switch on device mode
  * @flags: compatible specific SPI controller flags used at registration time
  */
 struct stm32_spi_cfg {
@@ -259,6 +260,7 @@ struct stm32_spi_cfg {
 	unsigned int baud_rate_div_min;
 	unsigned int baud_rate_div_max;
 	bool has_fifo;
+	bool has_device_mode;
 	u16 flags;
 };
 
@@ -1750,6 +1752,7 @@ static const struct stm32_spi_cfg stm32f4_spi_cfg = {
 	.baud_rate_div_min = STM32F4_SPI_BR_DIV_MIN,
 	.baud_rate_div_max = STM32F4_SPI_BR_DIV_MAX,
 	.has_fifo = false,
+	.has_device_mode = false,
 	.flags = SPI_MASTER_MUST_TX,
 };
 
@@ -1774,6 +1777,7 @@ static const struct stm32_spi_cfg stm32h7_spi_cfg = {
 	.baud_rate_div_min = STM32H7_SPI_MBR_DIV_MIN,
 	.baud_rate_div_max = STM32H7_SPI_MBR_DIV_MAX,
 	.has_fifo = true,
+	.has_device_mode = true,
 };
 
 static const struct of_device_id stm32_spi_of_match[] = {
@@ -1798,8 +1802,16 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	bool device_mode;
 	int ret;
+	const char *compatible =
+		of_match_device(pdev->dev.driver->of_match_table, &pdev->dev)->compatible;
+	const struct stm32_spi_cfg *cfg = (const struct stm32_spi_cfg *)
+		of_device_get_match_data(&pdev->dev);
 
 	device_mode = of_property_read_bool(np, "spi-slave");
+	if (!cfg->has_device_mode && device_mode) {
+		dev_err(&pdev->dev, "spi-slave not yet supported with %s\n", compatible);
+		return -EPERM;
+	}
 
 	if (device_mode)
 		ctrl = devm_spi_alloc_slave(&pdev->dev, sizeof(struct stm32_spi));
@@ -1817,9 +1829,7 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	spi->device_mode = device_mode;
 	spin_lock_init(&spi->lock);
 
-	spi->cfg = (const struct stm32_spi_cfg *)
-		of_match_device(pdev->dev.driver->of_match_table,
-				&pdev->dev)->data;
+	spi->cfg = cfg;
 
 	spi->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(spi->base))
-- 
2.25.1