i2c: stm32f7: unmap DMA mapped buffer

Before each I2C transfer using DMA, the I2C buffer is DMA'pped to make
sure the memory buffer is DMA'able. This is handle in the function
`stm32_i2c_prep_dma_xfer()`.
If the transfer fails for any reason the I2C buffer must be unmap.
Use the dma_callback to factorize the code and fix this issue.

Note that the `stm32f7_i2c_dma_callback()` is now called in case of DMA
transfer success and error and that the `complete()` on the dma_complete
completion structure is done inconditionnally in case of transfer
success or error as well as the `dmaengine_terminate_async()`.
This is allowed as a `complete()` in case transfer error has no effect
as well as a `dmaengine_terminate_async()` on a transfer success.

Also fix the unneeded cast and remove not more needed variables.

Fixes: 7ecc8cfde553 ("i2c: i2c-stm32f7: Add DMA support")
Signed-off-by: Clément Le Goffic <clement.legoffic@foss.st.com>
Cc: <stable@vger.kernel.org> # v4.18+
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20250704-i2c-upstream-v4-2-84a095a2c728@foss.st.com

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 817d081460c23cddccd4640f775156bffcdb3269..73a7b8894c0df1f98556d0d2081865b9e14a47aa 100644 (file)
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -739,10 +739,11 @@ static void stm32f7_i2c_disable_dma_req(struct stm32f7_i2c_dev *i2c_dev)
 
 static void stm32f7_i2c_dma_callback(void *arg)
 {
-       struct stm32f7_i2c_dev *i2c_dev = (struct stm32f7_i2c_dev *)arg;
+       struct stm32f7_i2c_dev *i2c_dev = arg;
        struct stm32_i2c_dma *dma = i2c_dev->dma;
 
        stm32f7_i2c_disable_dma_req(i2c_dev);
+       dmaengine_terminate_async(dma->chan_using);
        dma_unmap_single(i2c_dev->dev, dma->dma_buf, dma->dma_len,
                         dma->dma_data_dir);
        complete(&dma->dma_complete);
@@ -1510,7 +1511,6 @@ static irqreturn_t stm32f7_i2c_handle_isr_errs(struct stm32f7_i2c_dev *i2c_dev,
        u16 addr = f7_msg->addr;
        void __iomem *base = i2c_dev->base;
        struct device *dev = i2c_dev->dev;
-       struct stm32_i2c_dma *dma = i2c_dev->dma;
 
        /* Bus error */
        if (status & STM32F7_I2C_ISR_BERR) {
@@ -1551,10 +1551,8 @@ static irqreturn_t stm32f7_i2c_handle_isr_errs(struct stm32f7_i2c_dev *i2c_dev,
        }
 
        /* Disable dma */
-       if (i2c_dev->use_dma) {
-               stm32f7_i2c_disable_dma_req(i2c_dev);
-               dmaengine_terminate_async(dma->chan_using);
-       }
+       if (i2c_dev->use_dma)
+               stm32f7_i2c_dma_callback(i2c_dev);
 
        i2c_dev->master_mode = false;
        complete(&i2c_dev->complete);
@@ -1600,7 +1598,6 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
 {
        struct stm32f7_i2c_dev *i2c_dev = data;
        struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
-       struct stm32_i2c_dma *dma = i2c_dev->dma;
        void __iomem *base = i2c_dev->base;
        u32 status, mask;
        int ret;
@@ -1619,10 +1616,8 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
                dev_dbg(i2c_dev->dev, "<%s>: Receive NACK (addr %x)\n",
                        __func__, f7_msg->addr);
                writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
-               if (i2c_dev->use_dma) {
-                       stm32f7_i2c_disable_dma_req(i2c_dev);
-                       dmaengine_terminate_async(dma->chan_using);
-               }
+               if (i2c_dev->use_dma)
+                       stm32f7_i2c_dma_callback(i2c_dev);
                f7_msg->result = -ENXIO;
        }
 
@@ -1640,8 +1635,7 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
                        ret = wait_for_completion_timeout(&i2c_dev->dma->dma_complete, HZ);
                        if (!ret) {
                                dev_dbg(i2c_dev->dev, "<%s>: Timed out\n", __func__);
-                               stm32f7_i2c_disable_dma_req(i2c_dev);
-                               dmaengine_terminate_async(dma->chan_using);
+                               stm32f7_i2c_dma_callback(i2c_dev);
                                f7_msg->result = -ETIMEDOUT;
                        }
                }