linux-kernel - [PATCH 1/6] spi: stm32: fixes pm

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Message-ID: <1625042723-661-2-git-send-email-alain.volmat@foss.st.com>
Date:   Wed, 30 Jun 2021 10:45:18 +0200
From:   Alain Volmat <alain.volmat@...s.st.com>
To:     <broonie@...nel.org>, <amelie.delaunay@...s.st.com>
CC:     <mcoquelin.stm32@...il.com>, <alexandre.torgue@...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>, <fabrice.gasnier@...s.st.com>,
        <alain.volmat@...s.st.com>
Subject: [PATCH 1/6] spi: stm32: fixes pm_runtime calls in probe/remove

the pm_runtime is not fully configured (delay not setted).
Add pm_runtime calls in probe/probe error path and remove
in order to be consistent in all places in ordering and
ensure that pm_runtime is disabled prior to resources used
by the SPI controller.

This patch also fixes the 2 following warnings on driver remove:
WARNING: CPU: 0 PID: 743 at drivers/clk/clk.c:594 clk_core_disable_lock+0x18/0x24
WARNING: CPU: 0 PID: 743 at drivers/clk/clk.c:476 clk_unprepare+0x24/0x2c

Fixes: 038ac869c9d2 ("spi: stm32: add runtime PM support")

Signed-off-by: Amelie Delaunay <amelie.delaunay@...s.st.com>
Signed-off-by: Alain Volmat <alain.volmat@...s.st.com>
---
 drivers/spi/spi-stm32.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 8ffcffbb8157..fe35c5cfb820 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -162,6 +162,8 @@
 #define SPI_3WIRE_TX		3
 #define SPI_3WIRE_RX		4
 
+#define STM32_SPI_AUTOSUSPEND_DELAY		1	/* 1 ms */
+
 /*
  * use PIO for small transfers, avoiding DMA setup/teardown overhead for drivers
  * without fifo buffers.
@@ -1924,7 +1926,11 @@ static int stm32_spi_probe(struct platform_device *pdev)
 	if (spi->dma_tx || spi->dma_rx)
 		master->can_dma = stm32_spi_can_dma;
 
+	pm_runtime_set_autosuspend_delay(&pdev->dev,
+					 STM32_SPI_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
 	ret = spi_register_master(master);
@@ -1934,12 +1940,18 @@ static int stm32_spi_probe(struct platform_device *pdev)
 		goto err_pm_disable;
 	}
 
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
 	dev_info(&pdev->dev, "driver initialized\n");
 
 	return 0;
 
 err_pm_disable:
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
 err_dma_release:
 	if (spi->dma_tx)
 		dma_release_channel(spi->dma_tx);
@@ -1956,9 +1968,16 @@ static int stm32_spi_remove(struct platform_device *pdev)
 	struct spi_master *master = platform_get_drvdata(pdev);
 	struct stm32_spi *spi = spi_master_get_devdata(master);
 
+	pm_runtime_get_sync(&pdev->dev);
+
 	spi_unregister_master(master);
 	spi->cfg->disable(spi);
 
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+
 	if (master->dma_tx)
 		dma_release_channel(master->dma_tx);
 	if (master->dma_rx)
@@ -1966,7 +1985,6 @@ static int stm32_spi_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(spi->clk);
 
-	pm_runtime_disable(&pdev->dev);
 
 	pinctrl_pm_select_sleep_state(&pdev->dev);
 
-- 
2.25.1