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SubjectRe: [PATCH v3 2/5] dmaengine: Add STM32 DMAMUX driver
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On 07/22/2017 08:51 AM, Vinod Koul wrote:
> On Thu, Jul 06, 2017 at 02:20:20PM +0200, Pierre-Yves MORDRET wrote:
>> +static int stm32_dmamux_probe(struct platform_device *pdev)
>> +{
>> + struct device_node *node = pdev->dev.of_node;
>> + struct device_node *dma_node;
>> + struct stm32_dmamux_data *stm32_dmamux;
>> + struct resource *res;
>> + void __iomem *iomem;
>> + int i, ret;
>> +
>> + if (!node)
>> + return -ENODEV;
>> +
>> + stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux),
>> + GFP_KERNEL);
>> + if (!stm32_dmamux)
>> + return -ENOMEM;
>> +
>> + dma_node = of_parse_phandle(node, "dma-masters", 0);
>> + if (!dma_node) {
>> + dev_err(&pdev->dev, "Can't get DMA master node\n");
>> + return -ENODEV;
>> + }
>> +
>> + if (device_property_read_u32(&pdev->dev, "dma-channels",
>> + &stm32_dmamux->dmamux_channels))
>> + stm32_dmamux->dmamux_channels = STM32_DMAMUX_MAX_CHANNELS;
>> +
>> + if (device_property_read_u32(&pdev->dev, "dma-requests",
>> + &stm32_dmamux->dmamux_requests))
>> + stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
>
> I think defaults should be warned here too
>

ok

>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res)
>> + return -ENODEV;
>> +
>> + iomem = devm_ioremap_resource(&pdev->dev, res);
>> + if (!iomem)
>> + return -ENOMEM;
>> +
>> + spin_lock_init(&stm32_dmamux->lock);
>> +
>> + stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(stm32_dmamux->clk)) {
>> + dev_info(&pdev->dev, "Missing controller clock\n");
>
> Can you check for EPROBE_DEFER and print only for if that is not the error
> otherwise we end up sapmming with defered probe issues
>

This is what you meant ?
if (IS_ERR(stm32_dmamux->clk) != EPROBE_DEFER) {
dev_info(&pdev->dev, "Missing controller clock\n");
return PTR_ERR(stm32_dmamux->clk);
}

OR

if (IS_ERR(stm32_dmamux->clk)) {
if (IS_ERR(stm32_dmamux->clk) != EPROBE_DEFER)
dev_info(&pdev->dev, "Missing controller clock\n");
return PTR_ERR(stm32_dmamux->clk);
}

>> +
>> +#ifndef __DMA_STM32_DMAMUX_H
>> +#define __DMA_STM32_DMAMUX_H
>> +
>> +#if defined(CONFIG_STM32_DMAMUX)
>> +int stm32_dmamux_set_config(struct device *dev, void *route_data, u32 chan_id);
>
> Why do we need a custom API in this case?
>

This API is called by DMA when a slave is requested by client. DMA can work
without DMAMUX this API has been put in place to configure DMAMUX whether client
is requesting a DMAMUX Channel instead of a DMA one.

Thanks
Py
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