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

commit d98bdd3a5b50446d8e010be5b04ce81c4eabf728 upstream.

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.

Fixes: 588eb93ea49f ("i2c: imx: add runtime pm support to improve the performance")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 3576b63a6c0374791e62ca9e16e7e435127dd133..3f40995c0ca9a1c2978b758c48723702488c13fd 100644 (file)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1487,9 +1487,7 @@ 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);
 
        /* remove adapter */
        dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
@@ -1498,17 +1496,21 @@ 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);