[U-Boot] [PATCH 09/12] IMX: add additional function for pinmux using an array

[Eric Nelson <eric.nelson@boundarydevices.com>]

Hi Tim,

On 04/28/2014 01:17 PM, Tim Harvey wrote:
 >
> Add new function that can take an array of iomux configs, an index, and
> a stride to allow a multi-dimentional array of pinmux values to be used
> to define pinmux values per cpu-type.
>
> This takes a different approach to previously proposed solutions which used
> multiple arrays of pad lists. The goal is to eliminate having these multiple
> arrays such as 'mx6q_uart1_pads' and 'mx6dl_uart1_pads' which are almost
> identical copies of each other except for the MX6Q/MX6DL prefix on the PAD.
>
I don't think a blind reference to the previously proposed solution
helps in understanding this patch, and an example would be more helpful.

> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
> ---
> v2:
>   - moved macros for declaring and using structs for array variant
>   - removed non-related whitespace cleanup
> ---
>   arch/arm/imx-common/iomux-v3.c             | 19 +++++++++++++++----
>   arch/arm/include/asm/imx-common/iomux-v3.h | 15 +++++++++++++++
>   2 files changed, 30 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/imx-common/iomux-v3.c b/arch/arm/imx-common/iomux-v3.c
> index b59b802..d3e1e30 100644
> --- a/arch/arm/imx-common/iomux-v3.c
> +++ b/arch/arm/imx-common/iomux-v3.c
> @@ -46,12 +46,23 @@ void imx_iomux_v3_setup_pad(iomux_v3_cfg_t pad)
>   #endif
>   }
>

It's odd that git generated removal and re-insertion of this bit:

> -void imx_iomux_v3_setup_multiple_pads(iomux_v3_cfg_t const *pad_list,
> -				      unsigned count)

I think 'start_offs' would be clearer than 'list'.

The function name ..._array() also doesn't really capture what's
going on here. Naming is hard though, and I'm not coming up
with something else.

Perhaps 'sparse', 'skip', or alternate?

> +/* configures a list of pads within an array of lists */
> +void imx_iomux_v3_setup_multiple_pads_array(iomux_v3_cfg_t const *pad_list,
> +					    unsigned count, unsigned list,
> +					    unsigned stride)
>   {
>   	iomux_v3_cfg_t const *p = pad_list;
>   	int i;
>
> -	for (i = 0; i < count; i++)
> -		imx_iomux_v3_setup_pad(*p++);
> +	p += list;
> +	for (i = 0; i < count; i++) {
> +		imx_iomux_v3_setup_pad(*p);
> +		p += stride;
> +	}
> +}
> +
> +void imx_iomux_v3_setup_multiple_pads(iomux_v3_cfg_t const *pad_list,
> +				      unsigned count)
> +{
> +	imx_iomux_v3_setup_multiple_pads_array(pad_list, count, 0, 1);
>   }
> diff --git a/arch/arm/include/asm/imx-common/iomux-v3.h b/arch/arm/include/asm/imx-common/iomux-v3.h
> index dec11a1..2f7a1cb 100644
> --- a/arch/arm/include/asm/imx-common/iomux-v3.h
> +++ b/arch/arm/include/asm/imx-common/iomux-v3.h
> @@ -167,7 +167,22 @@ typedef u64 iomux_v3_cfg_t;
>   #define GPIO_PORTF		(5 << GPIO_PORT_SHIFT)
>
>   void imx_iomux_v3_setup_pad(iomux_v3_cfg_t pad);
> +void imx_iomux_v3_setup_multiple_pads_array(iomux_v3_cfg_t const *pad_list,
> +					    unsigned count, unsigned list,
> +					    unsigned stride);

Ditto about function and parameter naming.

>   void imx_iomux_v3_setup_multiple_pads(iomux_v3_cfg_t const *pad_list,
>   				     unsigned count);
>

It doesn't get any simpler than this:

> +/* macros for declaring and using pinmux array */
> +#define IOMUX_PADS(x) (MX6Q_##x), (MX6DL_##x)

In a similar vein to my comment about Patch 8, I do wonder if a
minor extension of this will allow use with a single-variant
board though.

We have some custom designs that really only function with
one variant (usually i.MX6DQ) and it seems wrong to have
the other variant included.

> +#define SETUP_IOMUX_PAD(def)					\
> +if (is_cpu_type(MXC_CPU_MX6Q)) {				\
> +	imx_iomux_v3_setup_pad(MX6Q_##def);			\
> +} else {							\
> +	imx_iomux_v3_setup_pad(MX6DL_##def);			\
> +}
> +#define SETUP_IOMUX_PADS(x)					\
> +	imx_iomux_v3_setup_multiple_pads_array(x,		\
> +	ARRAY_SIZE(x)/2, is_cpu_type(MXC_CPU_MX6Q) ? 0 : 1, 2)
> +
>   #endif	/* __MACH_IOMUX_V3_H__*/
>

Please don't mis-interpret my comments as any form of Nack.

This patch moves the ball forward, and the approach of building
two lists into one prevents duplication of tables quite nicely.

Regards,


Eric