Re: [PATCH v2 3/3] dmaengine: imx-sdma: add device tree probe support

["Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>]

Hi Shawn,

On Fri, Jul 15, 2011 at 05:44:26PM +0800, Shawn Guo wrote:
> It adds device tree probe support for imx-sdma driver.
> 
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Cc: Vinod Koul <vinod.koul@intel.com>
> Cc: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  .../devicetree/bindings/dma/fsl-imx-sdma.txt       |   17 ++++++++
>  drivers/dma/imx-sdma.c                             |   41 ++++++++++++++++++-
>  2 files changed, 55 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
> 
> diff --git a/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
> new file mode 100644
> index 0000000..d1e3f44
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt
> @@ -0,0 +1,17 @@
> +* Freescale Smart Direct Memory Access (SDMA) Controller for i.MX
> +
> +Required properties:
> +- compatible : Should be "fsl,<chip>-sdma"
> +- reg : Should contain SDMA registers location and length
> +- interrupts : Should contain SDMA interrupt
> +- fsl,sdma-ram-script-name : Should contain the full path of SDMA RAM
> +  scripts firmware
> +
> +Examples:
> +
> +sdma@83fb0000 {
> +	compatible = "fsl,imx51-sdma", "fsl,imx35-sdma";
> +	reg = <0x83fb0000 0x4000>;
> +	interrupts = <6>;
> +	fsl,sdma-ram-script-name = "sdma-imx51.bin";
> +};
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 6b839a2..20504f0 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -32,6 +32,8 @@
>  #include <linux/slab.h>
>  #include <linux/platform_device.h>
>  #include <linux/dmaengine.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  
>  #include <asm/irq.h>
>  #include <mach/sdma.h>
> @@ -331,6 +333,12 @@ static struct platform_device_id sdma_devtypes[] = {
>  	}
>  };
>  
> +static const struct of_device_id sdma_dt_ids[] = {
> +	{ .compatible = "fsl,imx31-sdma", .data = &sdma_devtypes[IMX31_SDMA], },
> +	{ .compatible = "fsl,imx35-sdma", .data = &sdma_devtypes[IMX35_SDMA], },
> +	{ /* sentinel */ }
> +};
> +
>  #define SDMA_H_CONFIG_DSPDMA	(1 << 12) /* indicates if the DSPDMA is used */
>  #define SDMA_H_CONFIG_RTD_PINS	(1 << 11) /* indicates if Real-Time Debug pins are enabled */
>  #define SDMA_H_CONFIG_ACR	(1 << 4)  /* indicates if AHB freq /core freq = 2 or 1 */
> @@ -1249,6 +1257,10 @@ err_dma_alloc:
>  
>  static int __init sdma_probe(struct platform_device *pdev)
>  {
> +	const struct of_device_id *of_id =
> +			of_match_device(sdma_dt_ids, &pdev->dev);
> +	struct device_node *np = pdev->dev.of_node;
> +	const char *fw_name;
fw_name could have a more local scope.

>  	int ret;
>  	int irq;
>  	struct resource *iores;
> @@ -1264,7 +1276,7 @@ static int __init sdma_probe(struct platform_device *pdev)
>  
>  	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	irq = platform_get_irq(pdev, 0);
> -	if (!iores || irq < 0 || !pdata) {
> +	if (!iores || irq < 0) {
>  		ret = -EINVAL;
>  		goto err_irq;
>  	}
> @@ -1294,6 +1306,8 @@ static int __init sdma_probe(struct platform_device *pdev)
>  	if (!sdma->script_addrs)
>  		goto err_alloc;
>  
> +	if (of_id)
> +		pdev->id_entry = of_id->data;
I don't know much about of (yet), is it allowed to assign to
pdev->id_entry?

>  	sdma->devtype = pdev->id_entry->driver_data;
>  
>  	dma_cap_set(DMA_SLAVE, sdma->dma_device.cap_mask);
> @@ -1324,10 +1338,30 @@ static int __init sdma_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_init;
>  
> -	if (pdata->script_addrs)
> +	if (pdata && pdata->script_addrs)
>  		sdma_add_scripts(sdma, pdata->script_addrs);
>  
> -	sdma_get_firmware(sdma, pdata->fw_name);
> +	if (pdata) {
> +		sdma_get_firmware(sdma, pdata->fw_name);
> +	} else {
> +		/*
> +		 * Because that device tree does not encode ROM script address,
> +		 * the RAM script in firmware is mandatory for device tree
> +		 * probe, otherwise it fails.
> +		 */
> +		ret = of_property_read_string(np, "fsl,sdma-ram-script-name",
> +					      &fw_name);
> +		if (ret) {
> +			dev_err(&pdev->dev, "failed to get firmware name\n");
> +			goto err_init;
> +		}
> +
> +		ret = sdma_get_firmware(sdma, fw_name);
> +		if (ret) {
> +			dev_err(&pdev->dev, "failed to get firmware\n");
> +			goto err_init;
> +		}
> +	}
>  
>  	sdma->dma_device.dev = &pdev->dev;
>  
> @@ -1375,6 +1409,7 @@ static int __exit sdma_remove(struct platform_device *pdev)
>  static struct platform_driver sdma_driver = {
>  	.driver		= {
>  		.name	= "imx-sdma",
> +		.of_match_table = sdma_dt_ids,
>  	},
>  	.id_table	= sdma_devtypes,
>  	.remove		= __exit_p(sdma_remove),
> -- 
> 1.7.4.1
> 
> 
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> 

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |