[U-Boot] [PATCH] mtd: nand: fsl-ifc: fix support of multiple NAND devices

[Scott Wood]

On Tue, Oct 17, 2017 at 10:00:45AM +0200, Kurt Kanzenbach wrote:
> Currently the chipselect used to identify the corresponding NAND chip is stored
> at the controller and only set during fsl_ifc_chip_init(). This way, only the
> last NAND chip is working, as the previous value of cs_nand gets overwritten.
> 
> In order to solve this issue the chipselect is moved from the controller to the
> NAND chip structure. Thus, the correct chipselect for each NAND chip operation
> is used.
> 
> Tested on hardware with two NAND chips connected to the IFC controller.
> 
> Signed-off-by: Kurt Kanzenbach <kurt at linutronix.de>
> ---
>  drivers/mtd/nand/fsl_ifc_nand.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
> index bc6bdc9b2c..57737dbe94 100644
> --- a/drivers/mtd/nand/fsl_ifc_nand.c
> +++ b/drivers/mtd/nand/fsl_ifc_nand.c
> @@ -36,6 +36,7 @@ struct fsl_ifc_mtd {
>  
>  	struct device *dev;
>  	int bank;               /* Chip select bank number                */
> +	unsigned int cs_nand;   /* On which chipsel NAND is connected	  */

This is redundant with "bank" -- just do like the Linux driver does
and write "priv->bank << IFC_NAND_CSEL_SHIFT" directly to the register
when needed.

> -static int fsl_ifc_sram_init(uint32_t ver)
> +static int fsl_ifc_sram_init(struct mtd_info *mtd, uint32_t ver)
>  {
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);

Could pass in priv instead of mtd to make it more like the Linux driver. 
It's best to avoid gratuitous differences.

-Scott