linux-kernel - Re: [PATCH v2] spi: pic32: Retire dma_request_slave_channel

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Date:   Thu, 21 Nov 2019 11:15:36 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <broonie@...nel.org>, <geert@...ux-m68k.org>
CC:     <vkoul@...nel.org>, <linux-spi@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] spi: pic32: Retire dma_request_slave_channel_compat()



On 21/11/2019 11.14, Peter Ujfalusi wrote:
> There is no reason to use the dma_request_slave_channel_compat() as no
> filter function and parameter is provided.
> 
> Switch the driver to use dma_request_chan() instead and add support for
> deferred probing against DMA channel.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
> ---
> Hi,
> 
> Changes since v1:
> - Handle deferred probing against DMA channel request.
> 
> Trying to crack down on the use of dma_request_slave_channel_compat() in the
> tree...
> 
> Only compile tested!
> 
> Regards,
> Peter
> 
>  drivers/spi/spi-pic32.c | 46 +++++++++++++++++++++++++++--------------
>  1 file changed, 30 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/spi/spi-pic32.c b/drivers/spi/spi-pic32.c
> index 69f517ec59c6..bb6a6643bcd3 100644
> --- a/drivers/spi/spi-pic32.c
> +++ b/drivers/spi/spi-pic32.c
> @@ -606,25 +606,30 @@ static void pic32_spi_cleanup(struct spi_device *spi)
>  	gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
>  }
>  
> -static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
> +static int pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
>  {
>  	struct spi_master *master = pic32s->master;
> -	dma_cap_mask_t mask;
> +	int ret = 0;
>  
> -	dma_cap_zero(mask);
> -	dma_cap_set(DMA_SLAVE, mask);
> +	master->dma_rx = dma_request_chan(dev, "spi-rx");
> +	if (IS_ERR(master->dma_rx)) {
> +		if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER)
> +			ret = -EPROBE_DEFER;
> +		else
> +			dev_warn(dev, "RX channel not found.\n");
>  
> -	master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
> -							  dev, "spi-rx");
> -	if (!master->dma_rx) {
> -		dev_warn(dev, "RX channel not found.\n");
> +		master->dma_rx = NULL;
>  		goto out_err;
>  	}
>  
> -	master->dma_tx = dma_request_slave_channel_compat(mask, NULL, NULL,
> -							  dev, "spi-tx");
> -	if (!master->dma_tx) {
> -		dev_warn(dev, "TX channel not found.\n");
> +	master->dma_tx = dma_request_chan(dev, "spi-tx");
> +	if (IS_ERR(master->dma_tx)) {
> +		if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER)
> +			ret = -EPROBE_DEFER;
> +		else
> +			dev_warn(dev, "RX channel not found.\n");

Sigh, copy-paste :(
s/RX/TX

> +
> +		master->dma_tx = NULL;
>  		goto out_err;
>  	}
>  
> @@ -634,14 +639,20 @@ static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
>  	/* DMA chnls allocated and prepared */
>  	set_bit(PIC32F_DMA_PREP, &pic32s->flags);
>  
> -	return;
> +	return 0;
>  
>  out_err:
> -	if (master->dma_rx)
> +	if (master->dma_rx) {
>  		dma_release_channel(master->dma_rx);
> +		master->dma_rx = NULL;
> +	}
>  
> -	if (master->dma_tx)
> +	if (master->dma_tx) {
>  		dma_release_channel(master->dma_tx);
> +		master->dma_tx = NULL;
> +	}
> +
> +	return ret;
>  }
>  
>  static void pic32_spi_dma_unprep(struct pic32_spi *pic32s)
> @@ -776,7 +787,10 @@ static int pic32_spi_probe(struct platform_device *pdev)
>  	master->unprepare_transfer_hardware	= pic32_spi_unprepare_hardware;
>  
>  	/* optional DMA support */
> -	pic32_spi_dma_prep(pic32s, &pdev->dev);
> +	ret = pic32_spi_dma_prep(pic32s, &pdev->dev);
> +	if (ret)
> +		goto err_bailout;
> +
>  	if (test_bit(PIC32F_DMA_PREP, &pic32s->flags))
>  		master->can_dma	= pic32_spi_can_dma;
>  
> 

- Péter

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