Re: [PATCH 1/4] mtd: nand: atmel: Rework driver to separate nfc and nand nodes

[Josh Wu]

Hi, Boris

On 12/5/2014 6:30 AM, Boris Brezillon wrote:
> mtd: nand: atmel: Update DT documentation after splitting NFC and NAND
>
> The NAND and NFC (NAND Flash Controller) were linked together with a
> parent <-> child relationship.
>
> This model has several drawbacks:
> - it does not allow for multiple NAND chip handling while the controller
>    support multi-chip (even though the driver is not ready yet)
> - it mixes NAND partitions and NFC nodes at the same level (which is a bit
>    disturbing)
> - the introduction of the EBI bus implies defining NAND chips under the
>    EBI node, and the ranges available under the EBI node should be
>    restricted to EBI address space, while the NFC references several
>    registers outside of these EBI ranges.
>
> Move the NFC node outside of the NAND node, to get a more future-proof
> DT representation.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
I'm fine with this patch.
Acked-by: Josh Wu <josh.wu@xxxxxxxxx>

Best Regards,
Josh Wu

> ---
>   drivers/mtd/nand/atmel_nand.c | 76 ++++++++++++++++++++++++++++++++++---------
>   1 file changed, 61 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index 19d1e9d..0239fe6 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -123,6 +123,7 @@ struct atmel_nand_host {
>   	struct dma_chan		*dma_chan;
>   
>   	struct atmel_nfc	*nfc;
> +	bool			wait_for_nfc;
>   
>   	bool			has_pmecc;
>   	u8			pmecc_corr_cap;
> @@ -1423,6 +1424,12 @@ static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
>   		ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
>   }
>   
> +static const struct of_device_id atmel_nand_nfc_match[] = {
> +	{ .compatible = "atmel,sama5d3-nfc" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, atmel_nand_nfc_match);
> +
>   static int atmel_of_init_port(struct atmel_nand_host *host,
>   			      struct device_node *np)
>   {
> @@ -1431,6 +1438,7 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
>   	int ecc_mode;
>   	struct atmel_nand_data *board = &host->board;
>   	enum of_gpio_flags flags = 0;
> +	struct device_node *child;
>   
>   	if (of_property_read_u32(np, "atmel,nand-addr-offset", &val) == 0) {
>   		if (val >= 32) {
> @@ -1467,8 +1475,30 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
>   
>   	host->has_pmecc = of_property_read_bool(np, "atmel,has-pmecc");
>   
> -	/* load the nfc driver if there is */
> -	of_platform_populate(np, NULL, NULL, host->dev);
> +	/*
> +	 * Backward compatibility with DTs defining the NFC node as their
> +	 * child.
> +	 * The new model reference the NFC so that we can define several
> +	 * chip controlled by the same controller.
> +	 */
> +	for_each_available_child_of_node(np, child) {
> +		/*
> +		 * If we find an NFC node under the NAND node, then populate
> +		 * the device so that it can be probed, and wait for it.
> +		 */
> +		if (of_match_node(atmel_nand_nfc_match, child)) {
> +			of_platform_populate(np, NULL, NULL, host->dev);
> +			host->wait_for_nfc = true;
> +			break;
> +		}
> +	}
> +
> +	/*
> +	 * If there's an atmel,nfc property we should access the NAND
> +	 * through the NFC.
> +	 */
> +	if (of_property_read_bool(np, "atmel,nfc"))
> +		host->wait_for_nfc = true;
>   
>   	if (!(board->ecc_mode == NAND_ECC_HW) || !host->has_pmecc)
>   		return 0;	/* Not using PMECC */
> @@ -2032,10 +2062,6 @@ static int atmel_nand_probe(struct platform_device *pdev)
>   	if (!host)
>   		return -ENOMEM;
>   
> -	res = platform_driver_register(&atmel_nand_nfc_driver);
> -	if (res)
> -		dev_err(&pdev->dev, "atmel_nand: can't register NFC driver\n");
> -
>   	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	host->io_base = devm_ioremap_resource(&pdev->dev, mem);
>   	if (IS_ERR(host->io_base)) {
> @@ -2089,6 +2115,13 @@ static int atmel_nand_probe(struct platform_device *pdev)
>   			goto err_nand_ioremap;
>   		}
>   	} else {
> +		/*
> +		 * If the NFC is not initialized (or not probed) and the device
> +		 * is asking to be accessed through the NFC then defer the
> +		 * probe.
> +		 */
> +		if (host->wait_for_nfc)
> +			return -EPROBE_DEFER;
>   		res = atmel_nand_set_enable_ready_pins(mtd);
>   		if (res)
>   			goto err_nand_ioremap;
> @@ -2230,8 +2263,6 @@ static int atmel_nand_remove(struct platform_device *pdev)
>   	if (host->dma_chan)
>   		dma_release_channel(host->dma_chan);
>   
> -	platform_driver_unregister(&atmel_nand_nfc_driver);
> -
>   	return 0;
>   }
>   
> @@ -2303,12 +2334,6 @@ static int atmel_nand_nfc_remove(struct platform_device *pdev)
>   	return 0;
>   }
>   
> -static const struct of_device_id atmel_nand_nfc_match[] = {
> -	{ .compatible = "atmel,sama5d3-nfc" },
> -	{ /* sentinel */ }
> -};
> -MODULE_DEVICE_TABLE(of, atmel_nand_nfc_match);
> -
>   static struct platform_driver atmel_nand_nfc_driver = {
>   	.driver = {
>   		.name = "atmel_nand_nfc",
> @@ -2329,7 +2354,28 @@ static struct platform_driver atmel_nand_driver = {
>   	},
>   };
>   
> -module_platform_driver(atmel_nand_driver);
> +static int __init atmel_nand_init(void)
> +{
> +	int ret;
> +
> +	ret = platform_driver_register(&atmel_nand_nfc_driver);
> +	if (ret)
> +		return ret;
> +
> +	ret = platform_driver_register(&atmel_nand_driver);
> +	if (ret)
> +		platform_driver_unregister(&atmel_nand_nfc_driver);
> +
> +	return ret;
> +}
> +module_init(atmel_nand_init);
> +
> +static void __exit atmel_nand_exit(void)
> +{
> +	platform_driver_unregister(&atmel_nand_driver);
> +	platform_driver_unregister(&atmel_nand_nfc_driver);
> +}
> +module_exit(atmel_nand_exit);
>   
>   MODULE_LICENSE("GPL");
>   MODULE_AUTHOR("Rick Bronson");

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