[U-Boot] [PATCH v4 4/5] mtd: nand: omap: add CONFIG_SYS_NAND_DEVICE_WIDTH to determine NAND device bus-width

[Scott Wood]

On Wed, 2014-04-30 at 05:12 +0000, Gupta, Pekon wrote:
> Hi Scott,
> 
> >From: Scott Wood [mailto:scottwood at freescale.com]
> >>On Mon, 2014-04-28 at 17:11 +0530, Pekon Gupta wrote:
> >> +   CONFIG_SYS_NAND_DEVICE_WIDTH
> >> +	Specifies bus-width of the default NAND device connected to SoC.
> >> +	This config is useful for driver which cannot self initialize or
> >> +	parse ONFI parameter (like SPL drivers), or for supporting non-ONFI
> >> +	compliant devices.
> >> +	This config can take following values:
> >> +	- 8: x8 NAND devices is connected
> >> +	- 16: x16 NAND device is connected
> >
> >Please list here the drivers that pay attention to this config symbol.
> >
> Different drivers use different approach.

Precisely -- that's why I don't want it to look like this is a generic
option that all drivers use.

> - Some driver like omap_gpmc.c require users to hack their board file
>  and do NAND device-width configurations by themselves.

I'd call it configuration rather than hacking. :-)

> - Others drivers uses some different CONFIG_SYS_NAND_xx symbols
> which is not documented in doc/README.nand
> 
> - atmel_nand.c: uses CONFIG_SYS_NAND_DBW_16
> - fsl_ifc_nand.c:  depends on configuration done in board file
> - fsmc_nand.c: CONFIG_SYS_FSMC_NAND_16BIT
> - mpc5121_nfc.c: depends on configurations done in board file
> - mxc_nand.c: uses CONFIG_SYS_NAND_BUSWIDTH_16BIT
> - ndfc.c: uses CONFIG_SYS_NAND_BUSWIDTH_16BIT
> - tegra_nand.c: ??
> 
> I just realize OMAP driver can also _reuse_ CONFIG_SYS_NAND_BUSWIDTH_16BIT
> instead of adding new config. Is this okay ? I missed it because it wasn't documented.

Yes, just document it and list the drivers that use it.

-Scott