mfd: stm32-timers: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
index efcd4b9..add6033 100644 (file)
--- a/drivers/mfd/stm32-timers.c
+++ b/drivers/mfd/stm32-timers.c
@@ -167,10 +167,11 @@ static void stm32_timers_get_arr_size(struct stm32_timers *ddata)
        regmap_write(ddata->regmap, TIM_ARR, 0x0);
 }
 
-static void stm32_timers_dma_probe(struct device *dev,
+static int stm32_timers_dma_probe(struct device *dev,
                                   struct stm32_timers *ddata)
 {
        int i;
+       int ret = 0;
        char name[4];
 
        init_completion(&ddata->dma.completion);
@@ -179,14 +180,23 @@ static void stm32_timers_dma_probe(struct device *dev,
        /* Optional DMA support: get valid DMA channel(s) or NULL */
        for (i = STM32_TIMERS_DMA_CH1; i <= STM32_TIMERS_DMA_CH4; i++) {
                snprintf(name, ARRAY_SIZE(name), "ch%1d", i + 1);
-               ddata->dma.chans[i] = dma_request_slave_channel(dev, name);
+               ddata->dma.chans[i] = dma_request_chan(dev, name);
        }
-       ddata->dma.chans[STM32_TIMERS_DMA_UP] =
-               dma_request_slave_channel(dev, "up");
-       ddata->dma.chans[STM32_TIMERS_DMA_TRIG] =
-               dma_request_slave_channel(dev, "trig");
-       ddata->dma.chans[STM32_TIMERS_DMA_COM] =
-               dma_request_slave_channel(dev, "com");
+       ddata->dma.chans[STM32_TIMERS_DMA_UP] = dma_request_chan(dev, "up");
+       ddata->dma.chans[STM32_TIMERS_DMA_TRIG] = dma_request_chan(dev, "trig");
+       ddata->dma.chans[STM32_TIMERS_DMA_COM] = dma_request_chan(dev, "com");
+
+       for (i = STM32_TIMERS_DMA_CH1; i < STM32_TIMERS_MAX_DMAS; i++) {
+               if (IS_ERR(ddata->dma.chans[i])) {
+                       /* Save the first error code to return */
+                       if (PTR_ERR(ddata->dma.chans[i]) != -ENODEV && !ret)
+                               ret = PTR_ERR(ddata->dma.chans[i]);
+
+                       ddata->dma.chans[i] = NULL;
+               }
+       }
+
+       return ret;
 }
 
 static void stm32_timers_dma_remove(struct device *dev,
@@ -230,7 +240,11 @@ static int stm32_timers_probe(struct platform_device *pdev)
 
        stm32_timers_get_arr_size(ddata);
 
-       stm32_timers_dma_probe(dev, ddata);
+       ret = stm32_timers_dma_probe(dev, ddata);
+       if (ret) {
+               stm32_timers_dma_remove(dev, ddata);
+               return ret;
+       }
 
        platform_set_drvdata(pdev, ddata);