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i2c: rcar: avoid race when unregistering slave client

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After we disabled interrupts, there might still be an active one
running. Sync before clearing the pointer to the slave device.

Fixes: de20d1857d ("i2c: rcar: add slave support")
Reported-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2019-08-08 21:39:10 +02:00 committed by Wolfram Sang
parent 8fc3ae3b10
commit 7b814d852a
1 changed files with 7 additions and 4 deletions
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11
drivers/i2c/busses/i2c-rcar.c
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@ -139,6 +139,7 @@ struct rcar_i2c_priv {
enum dma_data_direction dma_direction;
struct reset_control *rstc;
int irq;
};
#define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent)
@ -861,9 +862,11 @@ static int rcar_unreg_slave(struct i2c_client *slave)
WARN_ON(!priv->slave);
/* disable irqs and ensure none is running before clearing ptr */
rcar_i2c_write(priv, ICSIER, 0);
rcar_i2c_write(priv, ICSCR, 0);
synchronize_irq(priv->irq);
priv->slave = NULL;
pm_runtime_put(rcar_i2c_priv_to_dev(priv));
@ -918,7 +921,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
struct i2c_adapter *adap;
struct device *dev = &pdev->dev;
struct i2c_timings i2c_t;
int irq, ret;
int ret;
/* Otherwise logic will break because some bytes must always use PIO */
BUILD_BUG_ON_MSG(RCAR_MIN_DMA_LEN < 3, "Invalid min DMA length");
@ -984,10 +987,10 @@ static int rcar_i2c_probe(struct platform_device *pdev)
pm_runtime_put(dev);
irq = platform_get_irq(pdev, 0);
ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv);
priv->irq = platform_get_irq(pdev, 0);
ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, 0, dev_name(dev), priv);
if (ret < 0) {
dev_err(dev, "cannot get irq %d\n", irq);
dev_err(dev, "cannot get irq %d\n", priv->irq);
goto out_pm_disable;
}