From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Cherian <george.cherian@ti.com>
Subject: Re: [PATCH v5 6/6] usb: musb: dsps: Enable sw babble control for
 newer silicon
Date: Thu, 22 May 2014 18:22:52 +0530
Message-ID: <537DF324.7040907@ti.com>
References: <1400740181-31213-1-git-send-email-george.cherian@ti.com> <1400740181-31213-7-git-send-email-george.cherian@ti.com> <537DE67A.10203@cogentembedded.com>
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To: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, linux-omap@vger.kernel.org
Cc: gregkh@linuxfoundation.org, balbi@ti.com, zonque@gmail.com, b-liu@ti.com
List-Id: linux-omap@vger.kernel.org

On 5/22/2014 5:28 PM, Sergei Shtylyov wrote:
> Hello.
>
> On 22-05-2014 10:29, George Cherian wrote:
>
>> Find whether we are running on newer silicon. The babble control
>> register reads 0x4 by default in newer silicon as opposed to 0
>> in old versions of AM335x. Based on this enable the sw babble
>> control logic.
>
>> Signed-off-by: George Cherian <george.cherian@ti.com>
>> ---
>>   drivers/usb/musb/musb_dsps.c | 38 
>> ++++++++++++++++++++++++++++++++------
>>   1 file changed, 32 insertions(+), 6 deletions(-)
>
>> diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
>> index 868caf8..2ced061 100644
>> --- a/drivers/usb/musb/musb_dsps.c
>> +++ b/drivers/usb/musb/musb_dsps.c
> [...]
>> @@ -469,6 +470,19 @@ static int dsps_musb_init(struct musb *musb)
>>       val &= ~(1 << wrp->otg_disable);
>>       dsps_writel(musb->ctrl_base, wrp->phy_utmi, val);
>>
>> +    /*
>> +     *  Check whether the dsps version has babble control enabled.
>
>    One space too many before this sentence.
>
>> +     * In latest silicon revision the babble control logic is enabled.
>> +     * If MUSB_BABBLE_CTL returns 0x4 then we have the babble control
>> +     * logic enabled.
>> +     */
>> +    val = dsps_readb(musb->mregs, MUSB_BABBLE_CTL);
>> +    if (val == MUSB_BABBLE_RCV_DISABLE) {
>> +        glue->sw_babble_enabled = true;
>> +        val |= MUSB_BABBLE_SW_SESSION_CTRL;
>> +        dsps_writeb(musb->mregs, MUSB_BABBLE_CTL, val);
>> +    }
>> +
>
>    Hm, from the register offset that you declared in the previous 
> patch, I got an impression that this is a new standard MUSB register? 
Its very AM335x MUSB specific register, not a standard one.
Unfortunately the designers put it as part of MUSB core regs.
> Shouldn't this check be done in the generic MUSB code then?
>
> WBR, Sergei
>


-- 
-George