From: Jaret Cantu <jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
To: Peter Chen <hzpeterchen-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
felipe.balbi-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Subject: Re: [PATCH v3] usb: phy: mxs: Add DT bindings to configure TX settings
Date: Wed, 23 Mar 2016 13:37:01 -0400 [thread overview]
Message-ID: <56F2D43D.1040404@timesys.com> (raw)
In-Reply-To: <20160323043638.GA18462@peterchendt>
On 03/23/2016 12:36 AM, Peter Chen wrote:
> On Mon, Mar 21, 2016 at 12:32:27PM -0400, Jaret Cantu wrote:
>> The TX settings can be calibrated for particular hardware. The
>> phy is reset by Linux, so this cannot be handled by the bootloader.
>>
>> The TRM mentions that the maximum resistance should be used for the
>> DN/DP calibration in order to pass USB certification.
>>
>> The values for the TX registers are poorly described in the TRM.
>> The meanings of the register values were taken from another
>> Freescale-provided document:
>> https://community.freescale.com/message/566147#comment-566912
>>
>> Signed-off-by: Jaret Cantu <jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
>> ---
>> v3. Added unit suffix (-ohms) to tx-cal-45-d*
>>
>> v2. Copying devicetree list
>> Removed prettifying extra whitespace
>> Removed unnecessary register rewrite on resume
>> Use min and max constants for clarity
>>
>> .../devicetree/bindings/phy/mxs-usb-phy.txt | 10 ++++
>> drivers/usb/phy/phy-mxs-usb.c | 58 ++++++++++++++++++++
>> 2 files changed, 68 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt
>> index 379b84a..1d25b04 100644
>> --- a/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt
>> +++ b/Documentation/devicetree/bindings/phy/mxs-usb-phy.txt
>> @@ -12,6 +12,16 @@ Required properties:
>> - interrupts: Should contain phy interrupt
>> - fsl,anatop: phandle for anatop register, it is only for imx6 SoC series
>>
>> +
>> + if (!of_property_read_u32(np, "fsl,tx-d-cal", &val) &&
>> + val >= MXS_PHY_TX_D_CAL_MIN && val <= MXS_PHY_TX_D_CAL_MAX) {
>> + /* scale to 4-bit value */
>> + val = (MXS_PHY_TX_D_CAL_MAX - val) * 0xF
>> + / (MXS_PHY_TX_D_CAL_MAX - MXS_PHY_TX_D_CAL_MIN);
>> + mxs_phy->tx_reg_mask |= GM_USBPHY_TX_D_CAL(~0);
>> + mxs_phy->tx_reg_set |= GM_USBPHY_TX_D_CAL(val);
>> + }
>> +
>
> I have tested "tx-d-cal", but it seems incorrect according to the xls you
> have provided, would you please check it again or am I wrong?
Gah! You're right. Some of the D_CAL values need to be rounded up to
match the xls. And even then, the value for 86 still doesn't play nice.
I was really hoping to avoid using a table for these values.
The TXCALDP/DN values use a much simpler 1-to-1 scale across the 16
possible register values and so are unaffected by a similar issue. I
rechecked their numbers just to be sure.
>
> dts changes:
>
> +&usbphy1 {
> + fsl,tx-d-cal = <109>;
> +};
> +
> +&usbphy2 {
> + fsl,tx-d-cal = <106>;
> +};
> +
>
> The phy1's tx-d-cal is 0x3, and phy2's tx-d-cal is 0x4 after PHY initialization,
> but according to xls, it should be 0x4 and 0x5.
>
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next prev parent reply other threads:[~2016-03-23 17:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1457040571-7775-1-git-send-email-jaret.cantu@timesys.com>
[not found] ` <1457040571-7775-1-git-send-email-jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-03-15 16:54 ` [PATCH v2] usb: phy: mxs: Add DT bindings to configure TX settings Jaret Cantu
[not found] ` <1458060853-15115-1-git-send-email-jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-03-18 21:19 ` Rob Herring
2016-03-21 16:32 ` [PATCH v3] " Jaret Cantu
[not found] ` <1458577947-12614-1-git-send-email-jaret.cantu-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-03-23 1:53 ` Peter Chen
2016-03-23 4:36 ` Peter Chen
2016-03-23 17:37 ` Jaret Cantu [this message]
[not found] ` <56F2D43D.1040404-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-03-23 18:17 ` Jaret Cantu
[not found] ` <56F2DDB7.7070700-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-03-24 2:21 ` Peter Chen
2016-03-30 10:29 ` Felipe Balbi
[not found] ` <874mboqmwh.fsf-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-03-31 6:49 ` Peter Chen
2016-06-08 21:27 ` Jaret Cantu
[not found] ` <57588DA8.4050000-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-06-09 2:41 ` Peter Chen
[not found] ` <CAL411-of2Phqx18LBaGt6FMg5DxaJesRYvrRzsfSNyJRopsUZQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-06-09 18:07 ` Justin Waters
[not found] ` <CAENNV6+978syhexzQber58xuai=grC2_TsVF3GmHCAp_Zj=HZQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-06-12 3:25 ` Peter Chen
2016-06-13 20:40 ` Jaret Cantu
[not found] ` <575F1A57.6030807-jEh4hwF5bVhBDgjK7y7TUQ@public.gmane.org>
2016-06-14 2:06 ` Peter Chen
2016-03-23 14:54 ` Rob Herring
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