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arm: mvebu: a38x: Configurable USB2 high-speed impedance threshold

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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@alliedtelesis.co.nz>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Joshua Scott
2020-11-09 10:14:08 +13:00
committed by Stefan Roese
parent 5115de8d64
commit 28f0cbcdd2
2 changed files with 9 additions and 3 deletions
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6
arch/arm/mach-mvebu/Kconfig
View File

@@ -30,6 +30,12 @@ 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
range 0x0 0x7
config ARMADA_XP
bool
select ARMADA_32BIT

6
arch/arm/mach-mvebu/serdes/a38x/high_speed_env_spec.c
View File

@@ -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},