[PATCH 1/3] i2c: at91: release DMA channels on remove and probe error

[Shengzhuo Wei]

at91_twi_configure_dma() requests exclusive tx/rx DMA channels, but
nothing ever releases them on driver detach, and the probe error path
after the channels are acquired (i2c_add_numbered_adapter() failure)
returns without releasing them either, because the remove callback is
not invoked after a failed probe.

Move the release into a helper, call it from the existing
configure-failure path, the adapter-registration failure path, and
at91_twi_remove().

Fixes: 60937b2cdbf9 ("i2c: at91: add dma support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Shengzhuo Wei <me@xxxxxxxx>
Assisted-by: GLM:5.3
---
 drivers/i2c/busses/i2c-at91-core.c   |  3 +++
 drivers/i2c/busses/i2c-at91-master.c | 12 +++++++++++-
 drivers/i2c/busses/i2c-at91.h        |  1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index b64adef778d4..8ca4556d9664 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -255,6 +255,7 @@ static int at91_twi_probe(struct platform_device *pdev)
 	if (rc) {
 		pm_runtime_disable(dev->dev);
 		pm_runtime_set_suspended(dev->dev);
+		at91_twi_dma_release(dev);
 
 		return rc;
 	}
@@ -270,6 +271,8 @@ static void at91_twi_remove(struct platform_device *pdev)
 
 	i2c_del_adapter(&dev->adapter);
 
+	at91_twi_dma_release(dev);
+
 	pm_runtime_disable(dev->dev);
 	pm_runtime_set_suspended(dev->dev);
 }
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index 894cedbca99f..68238cc8aee0 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -817,11 +817,21 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
 error:
 	if (ret != -EPROBE_DEFER)
 		dev_info(dev->dev, "can't get DMA channel, continue without DMA support\n");
+	at91_twi_dma_release(dev);
+	return ret;
+}
+
+void at91_twi_dma_release(struct at91_twi_dev *dev)
+{
+	struct at91_twi_dma *dma = &dev->dma;
+
 	if (dma->chan_rx)
 		dma_release_channel(dma->chan_rx);
 	if (dma->chan_tx)
 		dma_release_channel(dma->chan_tx);
-	return ret;
+	dma->chan_rx = NULL;
+	dma->chan_tx = NULL;
+	dev->use_dma = false;
 }
 
 static int at91_init_twi_recovery_gpio(struct platform_device *pdev,
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 942e9c3973bb..d68fcbbc3e0f 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -172,6 +172,7 @@ void at91_twi_irq_restore(struct at91_twi_dev *dev);
 void at91_init_twi_bus(struct at91_twi_dev *dev);
 
 void at91_init_twi_bus_master(struct at91_twi_dev *dev);
+void at91_twi_dma_release(struct at91_twi_dev *dev);
 int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
 			  struct at91_twi_dev *dev);
 

-- 
2.47.3