RE: [PATCH v2 1/2] ARM: dts: am335x-bone: add support for beaglebone NAND cape

2014-05-16 Thread Gupta, Pekon
Hi Ezequiel,

Sorry for delayed replies..

From: Ezequiel Garcia [mailto:ezequiel.gar...@free-electrons.com]
Pekon,

A few questions regarding this patch, despite the fact I'm not sure it will
ever be included.

On 20 Mar 01:04 PM, Pekon Gupta wrote: 
 +0x70 (MUX_MODE0 | PIN_INPUT_PULLUP )/* 
 gpmc_wait0.gpmc_wait0 */
 +0x74 (MUX_MODE7 | PIN_OUTPUT_PULLUP)/* 
 gpmc_wpn.gpio0_30 */

Is this output pin?
Yes, it's the Write Protect (WP) pin. And goes controller - device.



 +0x7c (MUX_MODE0 | PIN_OUTPUT_PULLUP)/* 
 gpmc_csn0.gpmc_csn0  */

Again: is this output pin?

Yes, this is Chip-select  and goes from controller - device.
Though it should already have external pull-up resistor on board, to avoid
glitches due to noise, and avoid device getting confused when SoC
is not driving anything (like before pin-muxing).


 +gpmc,wait-on-read = true;
 +gpmc,wait-on-write = true;

The devicetree binding says these wait properties are bool, so the above
should be:

   gpmc,wait-on-read;
   gpmc,wait-on-write;

But the problem is that there's no wait-pin defined, so this not enabled.

Could you explain what should be the correct binding? This is very confusing
for me.

I have fixed the above DT mapping in newer version of the patch [1].

Sorry, yes the wait-pin monitoring implementation is not cleanly done,
there is mix of platform_data and DT stuff. So in addition to updated DT patch
you need following patch to enable wait-pin monitoring in NAND driver.

http://www.spinics.net/lists/linux-omap/msg107253.html



with regards, pekon
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Re: [PATCH v2 1/2] ARM: dts: am335x-bone: add support for beaglebone NAND cape

2014-05-12 Thread Ezequiel Garcia
Pekon,

A few questions regarding this patch, despite the fact I'm not sure it will
ever be included.

On 20 Mar 01:04 PM, Pekon Gupta wrote:
 + 0x70 (MUX_MODE0 | PIN_INPUT_PULLUP )/* 
 gpmc_wait0.gpmc_wait0 */
 + 0x74 (MUX_MODE7 | PIN_OUTPUT_PULLUP)/* 
 gpmc_wpn.gpio0_30 */

Is this output pin?

 + 0x7c (MUX_MODE0 | PIN_OUTPUT_PULLUP)/* 
 gpmc_csn0.gpmc_csn0  */

Again: is this output pin?

 + gpmc,wait-on-read = true;
 + gpmc,wait-on-write = true;

The devicetree binding says these wait properties are bool, so the above
should be:

gpmc,wait-on-read;
gpmc,wait-on-write;

But the problem is that there's no wait-pin defined, so this not enabled.

Could you explain what should be the correct binding? This is very confusing
for me.

Thanks!
-- 
Ezequiel GarcĂ­a, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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