[U-Boot] [PATCH] imx: mx25: Remove SION bit in all pin-mux

[Benoît Thébaudeau]

Hi Michael,

On 24/01/2018 at 16:26, Michael Nazzareno Trimarchi wrote:
> On Wed, Jan 24, 2018 at 4:14 PM, Fabio Estevam <festevam at gmail.com> wrote:
>> On Wed, Jan 24, 2018 at 12:56 PM, Michael Trimarchi
>> <michael at amarulasolutions.com> wrote:
>>> SION bit should be used in the situation that we need
>>> to read back the value of a pin and should be set by
>>> default.

You remove this bit because it should be set by default? This sentence is
confusing.

>>> This can generate any kind of random malfunction
>>> as described in this thread.
>>>
>>> According to this thread:
>>> https://www.spinics.net/lists/linux-usb/msg162574.html

I can't find details about SION on a specific pin in this thread. Please
elaborate.

>>> We consider this an early bug so all the boards running imx25
>>> with a minimimal set of functionalities can be affected.
>>>
>>> As reported by this application note:
>>> https://www.nxp.com/docs/en/application-note/AN5078.pdf
>>>
>>> The software input on (SION) bit is an option to force an input
>>> path to be active regardless of the value driven by the
>>> corresponding module. It is used when the nature direction
>>> of a pin depending on selected alternative function is an output,
>>> but it is needed to read the real logic value on a pin.
>>>
>>> The SION bit can be used in:
>>> • Loopback: the module of a selected alternative function drives
>>> the pad and also receives the pad value as an input
>>> • GPIO capture: the module of a selected alternative function
>>> drives the pin and the value is captured by the GPIO
>>>
>>> Signed-off-by: Michael Trimarchi <michael at amarulasolutions.com>
>>> ---
>>> Refer-to:
>>>         MX25 USB timeout on ID 0951:1665 Kingston Technology Digital
>>>         DataTraveler SE9 64GB
>>
>> Glad you found a fix for the issue!
>>
> 
> The idea was to align to the other freescale architecture. I can
> create two patches on it
> 
> Michael
> 
>>
>>> ---
>>>  arch/arm/include/asm/arch-mx25/iomux-mx25.h | 680 ++++++++++++++--------------
>>>  1 file changed, 340 insertions(+), 340 deletions(-)
>>>
>>> diff --git a/arch/arm/include/asm/arch-mx25/iomux-mx25.h b/arch/arm/include/asm/arch-mx25/iomux-mx25.h
>>> index 5b2863e..2fcaf60 100644
>>> --- a/arch/arm/include/asm/arch-mx25/iomux-mx25.h
>>> +++ b/arch/arm/include/asm/arch-mx25/iomux-mx25.h
>>> @@ -30,481 +30,481 @@
>>>
>>>  /*                                                         PAD    MUX    ALT INPSE PATH PADCTRL */
>>>  enum {
>>> -       MX25_PAD_A10__A10                       = IOMUX_PAD(0x000, 0x008, 0x00, 0, 0, NO_PAD_CTRL),
>>> -       MX25_PAD_A10__GPIO_4_0                  = IOMUX_PAD(0x000, 0x008, 0x05, 0, 0, NO_PAD_CTRL),
>>> +       MX25_PAD_A10__A10                       = IOMUX_PAD(0x000, 0x008, 0, 0, 0, NO_PAD_CTRL),
>>> +       MX25_PAD_A10__GPIO_4_0                  = IOMUX_PAD(0x000, 0x008, 5, 0, 0, NO_PAD_CTRL),
>>
>> In many places in this patch you are only changing things like 0x00
>> --> 0 or 0x05--> 5, which just makes it harder to review.
>>
>> Please send a new version that only removes the SION bit.

Please make sure that these changes are not breaking anything for any board
(NEW_PAD_CTRL() can be used for these boards to restore SION if it really has to
be removed by default). SION is required in some cases, and it's unlikely to be
harmful, its main side effect being an increased power consumption.

Best regards,
Benoît