From: Wolfgang Grandegger <wg@grandegger•com>
To: avorontsov@ru•mvista.com
Cc: Linuxppc-dev@ozlabs•org
Subject: Re: [PATCH] [NAND] driver extension to support NAND on TQM85xx modules
Date: Wed, 04 Jun 2008 11:52:44 +0200 [thread overview]
Message-ID: <484665EC.30001@grandegger.com> (raw)
In-Reply-To: <20080530125057.GB13407@polina.dev.rtsoft.ru>
Hi Anton,
Anton Vorontsov wrote:
> On Fri, May 30, 2008 at 08:36:32AM +0200, Wolfgang Grandegger wrote:
>> This patch extends the FSL UPM NAND driver from Anton Vorontsov to
>> support for the TQM85xx modules. Unfortunately, the hardware does
>> not support the R/B pins of the NAND chip and therefore the specified
>> maximum delay time must used. It therefore re-introduces the chip-delay
>> property.
>>
>> Note: this patch is based on a patch Anton Vorontsov posted to this list:
>> See http://ozlabs.org/pipermail/linuxppc-dev/2008-April/055587.html.
>> It should show up mainstream soon.
>
> Personally, I like this patch. But OF people should approve "chip-delay"
> property. Though, the whole UPM NAND bindings are in the air still.
>
>> --- a/include/linux/of_gpio.h
>> +++ b/include/linux/of_gpio.h
>> @@ -15,7 +15,7 @@
>> #define __LINUX_OF_GPIO_H
>>
>> #include <linux/errno.h>
>> -#include <asm/gpio.h>
>> +#include <linux/gpio.h>
>
> This should be done separately.
I have a technical question. Do you understand why the Linux NAND FSL UPM
driver needs polling the R/B pin when writing out a sequence of bytes:
static void fun_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
{
struct fsl_upm_nand *fun = to_fsl_upm_nand(mtd);
int i;
for (i = 0; i < len; i++) {
out_8(fun->chip.IO_ADDR_W, buf[i]);
fun_wait_rnb(fun);
}
}
We do not need that in the corresponding U-Boot driver. On my board (not
having the R/B pin connected) I need a small delay of approx. 100 ns
instead to get it working properly.
Wolfgang.
next prev parent reply other threads:[~2008-06-04 9:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-30 6:36 [PATCH] [NAND] driver extension to support NAND on TQM85xx modules Wolfgang Grandegger
2008-05-30 12:50 ` Anton Vorontsov
2008-06-04 9:52 ` Wolfgang Grandegger [this message]
2008-06-04 11:58 ` Anton Vorontsov
2008-05-30 13:07 ` Kumar Gala
2008-05-30 13:57 ` Wolfgang Grandegger
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