[PATCH] i2c: imx: Make sure to unregister adapter on remove()

[Uwe Kleine-König]

If for whatever reasons pm_runtime_resume_and_get() fails and .remove() is
exited early, the i2c adapter stays around and the irq still calls its
handler, while the driver data and the register mapping go away. So if
later the i2c adapter is accessed or the irq triggers this results in
havoc accessing freed memory and unmapped registers.

So unregister the software resources even if resume failed, and only skip
the hardware access in that case.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 drivers/i2c/busses/i2c-imx.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index e9e2db68b9fb..7395560c13d0 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1572,9 +1572,7 @@ static int i2c_imx_remove(struct platform_device *pdev)
 	struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
 	int irq, ret;
 
-	ret = pm_runtime_resume_and_get(&pdev->dev);
-	if (ret < 0)
-		return ret;
+	ret = pm_runtime_get_sync(&pdev->dev);
 
 	hrtimer_cancel(&i2c_imx->slave_timer);
 
@@ -1585,17 +1583,21 @@ static int i2c_imx_remove(struct platform_device *pdev)
 	if (i2c_imx->dma)
 		i2c_imx_dma_free(i2c_imx);
 
-	/* setup chip registers to defaults */
-	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
-	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
-	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
-	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
+	if (ret == 0) {
+		/* setup chip registers to defaults */
+		imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
+		imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
+		imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
+		imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
+		clk_disable(i2c_imx->clk);
+	}
 
 	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
 	irq = platform_get_irq(pdev, 0);
 	if (irq >= 0)
 		free_irq(irq, i2c_imx);
-	clk_disable_unprepare(i2c_imx->clk);
+
+	clk_unprepare(i2c_imx->clk);
 
 	pm_runtime_put_noidle(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

base-commit: 6014cfa5bf32cf8c5c58b3cfd5ee0e1542c8a825
-- 
2.36.1