Re: [PATCH 2/2] OMAP4430: USB Host: Implement workaround for Errata i687

[Sergei Shtylyov <sshtylyov@mvista.com>]

Hello.

On 29-06-2012 13:11, Ruslan Bilovol wrote:

> The OMAP4 EHCI controller has the following defect (errata ID i687):

> Title:
> 	USB TLL Hold Timing Violation

> Description:
> 	There is a timing hold violation on an internal logic on
> 	the clock USB TLL path resulting in a systematic connection
> 	failure on the TLL link

> WORKAROUND:
> 	As part of workaround, next should be done:
> 	Set the I/O drive strength to 1.
> 	Depending which USB host subsystem is used,
> 	• Port B1 used: Set CONTROL.CONTROL_SMART2IO_PADCONF_2[11] USBB1_DR0_DS = 0x1
> 	• Port B2 used: Set CONTROL.CONTROL_SMART2IO_PADCONF_2[12] USBB2_DR0_DS = 0x1

> All OMAP4430 devices are impacted.

> Signed-off-by: Ruslan Bilovol<ruslan.bilovol@ti.com>
> ---
>   arch/arm/mach-omap2/usb-host.c |   17 +++++++++++++++++
>   1 files changed, 17 insertions(+), 0 deletions(-)

> diff --git a/arch/arm/mach-omap2/usb-host.c b/arch/arm/mach-omap2/usb-host.c
> index dde8a11..3a6f2a2 100644
> --- a/arch/arm/mach-omap2/usb-host.c
> +++ b/arch/arm/mach-omap2/usb-host.c
[...]
> @@ -252,6 +253,14 @@ void __init setup_4430ehci_io_mux(const enum usbhs_omap_port_mode *port_mode)
>   			OMAP_PIN_INPUT_PULLDOWN);
>   		omap_mux_init_signal("usbb1_ulpitll_dat7",
>   			OMAP_PIN_INPUT_PULLDOWN);
> +
> +		/* Errata i687: set I/O drive strength to 1 */
> +		if (cpu_is_omap443x()) {
> +			u32 val;

    Empty line after the declaration block wouldn't hurt...

> +			val = omap4_ctrl_pad_readl(OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_SMART2IO_PADCONF_2);
> +			val |= OMAP4_USBB1_DR0_DS_MASK;
> +			omap4_ctrl_pad_writel(val, OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_SMART2IO_PADCONF_2);
> +		}
>   			break;
>   	case OMAP_USBHS_PORT_MODE_UNUSED:
>   	default:
> @@ -309,6 +318,14 @@ void __init setup_4430ehci_io_mux(const enum usbhs_omap_port_mode *port_mode)
>   			OMAP_PIN_INPUT_PULLDOWN);
>   		omap_mux_init_signal("usbb2_ulpitll_dat7",
>   			OMAP_PIN_INPUT_PULLDOWN);
> +
> +		/* Errata i687: set I/O drive strength to 1 */
> +		if (cpu_is_omap443x()) {
> +			u32 val;

    Same here...

> +			val = omap4_ctrl_pad_readl(OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_SMART2IO_PADCONF_2);
> +			val |= OMAP4_USBB2_DR0_DS_MASK;
> +			omap4_ctrl_pad_writel(val, OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_SMART2IO_PADCONF_2);
> +		}
>   			break;
>   	case OMAP_USBHS_PORT_MODE_UNUSED:
>   	default:

WBR, Sergei
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