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SubjectRe: [PATCH 1/4] mtd: nand: atmel: Rework driver to separate nfc and nand nodes
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@free-electrons.com>
I'm fine with this patch.
Acked-by: Josh Wu <josh.wu@atmel.com>

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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