[PATCH] arm: mvebu: a38x: Configurable USB2 high-speed impedance threshold

[Stefan Roese]

On 06.11.20 05:08, Joshua Scott wrote:
> Hardware testing of a board using the Armada 385 has shown that an
> impedance threshold setting of 0x7 performs better in an eye-diagram
> test than with Marvell's recommended value 0x6.
> 
> As other boards may still perform better with Marvell's reccomended value,
> a configuration option is added with a default value of 0x6.
> 
> Signed-off-by: Joshua Scott <joshua.scott at alliedtelesis.co.nz>
> Cc: Stefan Roese <sr at denx.de.in>
> ---
>   arch/arm/mach-mvebu/Kconfig                           | 5 +++++
>   arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c | 6 +++---
>   2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig
> index 0d8e0922a2..bec011e584 100644
> --- a/arch/arm/mach-mvebu/Kconfig
> +++ b/arch/arm/mach-mvebu/Kconfig
> @@ -30,6 +30,11 @@ config ARMADA_38X
>   	select ARMADA_32BIT
>   	select HAVE_MVEBU_EFUSE
>   
> +config ARMADA_38X_HS_IMPEDANCE_THRESH
> +	hex  "Armada 38x USB 2.0 High-Speed Impedance Threshold (0x0 - 0x7)"
> +	depends on ARMADA_38X
> +	default 0x6
> +

Please add "range" here (range 0 7), so that no unsupported values can
be chosen here.

Other than that:

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

>   config ARMADA_XP
>   	bool
>   	select ARMADA_32BIT
> diff --git a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> index 2454730e6d..ae2a361104 100644
> --- a/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> +++ b/arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
> @@ -677,9 +677,9 @@ struct op_params usb2_power_up_params[] = {
>   	{0xc200c, 0x0 /*NA*/, 0xf000, {0x1000}, 0, 0},
>   	{0xc400c, 0x0 /*NA*/, 0xf000, {0x1000}, 0, 0},
>   	/* Change the High speed impedance threshold */
> -	{0xc0008, 0x0 /*NA*/, 0x700, {0x600}, 0, 0},
> -	{0xc2008, 0x0 /*NA*/, 0x700, {0x600}, 0, 0},
> -	{0xc4008, 0x0 /*NA*/, 0x700, {0x600}, 0, 0},
> +	{0xc0008, 0x0 /*NA*/, 0x700, {CONFIG_ARMADA_38X_HS_IMPEDANCE_THRESH << 8}, 0, 0},
> +	{0xc2008, 0x0 /*NA*/, 0x700, {CONFIG_ARMADA_38X_HS_IMPEDANCE_THRESH << 8}, 0, 0},
> +	{0xc4008, 0x0 /*NA*/, 0x700, {CONFIG_ARMADA_38X_HS_IMPEDANCE_THRESH << 8}, 0, 0},
>   	/* Change the squelch level of the receiver to meet the receiver electrical measurements (squelch and receiver sensitivity tests) */
>   	{0xc0014, 0x0 /*NA*/, 0xf, {0x8}, 0, 0},
>   	{0xc2014, 0x0 /*NA*/, 0xf, {0x8}, 0, 0},
> 


Viele Grüße,
Stefan

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