From: josh.wu@atmel•com (Josh Wu)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 6/6] mtd: ofpart: add compatible check for child nodes
Date: Thu, 13 Jun 2013 11:38:39 +0800 [thread overview]
Message-ID: <51B93EBF.5050207@atmel.com> (raw)
In-Reply-To: <CAN8TOE-JuVAAKBR84cbs9Hge+bQ6hQpFyoSDywKvCMe7h+Lc4g@mail.gmail.com>
Hi, Brian
On 6/12/2013 7:34 AM, Brian Norris wrote:
> Hi Josh,
>
> On Mon, Jun 10, 2013 at 3:26 AM, Josh Wu <josh.wu@atmel•com> wrote:
>> If the child node has compatible property then it is a driver not partition.
>>
>> Signed-off-by: Josh Wu <josh.wu@atmel•com>
>> ---
>> drivers/mtd/ofpart.c | 14 +++++++++++++-
>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
>> index 553d6d6..61ce1f8 100644
>> --- a/drivers/mtd/ofpart.c
>> +++ b/drivers/mtd/ofpart.c
>> @@ -20,6 +20,10 @@
>> #include <linux/slab.h>
>> #include <linux/mtd/partitions.h>
>>
>> +static bool node_has_compatible(struct device_node *pp, int *len)
>> +{
>> + return of_get_property(pp, "compatible", len);
>> +}
> The way the interface is named, it seems like a user only would ever
> need the bool return value, not the implicit 'len' return value. So I
> would write it like this:
>
> static bool node_has_compatible(struct device_node *pp)
> {
> return of_get_property(pp, "compatible", NULL);
> }
yes, this is exactly is what I want. I didn't check the *len can be NULL
or not. thanks.
>
>> static int parse_ofpart_partitions(struct mtd_info *master,
>> struct mtd_partition **pparts,
>> struct mtd_part_parser_data *data)
>> @@ -40,8 +44,13 @@ static int parse_ofpart_partitions(struct mtd_info *master,
>> /* First count the subnodes */
>> pp = NULL;
>> nr_parts = 0;
>> - while ((pp = of_get_next_child(node, pp)))
>> + while ((pp = of_get_next_child(node, pp))) {
>> + int len;
>> + if (node_has_compatible(pp, &len))
> Then this would just be:
>
> if (node_has_compatible(pp))
> ...
> etc. (rest snipped)
>
> On a more important question, why does a NAND device node have
> sub-nodes that are not partitions? And if such devices exist, wouldn't
> it be more foolproof to establish a "compatible" property for ofpart
> partitions?
In my case, we have a Atmel NAND flash driver/device which is work for
all series of SAM9/SAMA5D3 chip.
And since in the new chip SAMA5D3 which has a NAND Flash Controller support.
So to enable NAND flash controller, I should either write a compatible
driver like atmel,sama5-nand, which is
just old device property plus NFC regs and NFC properties, that became
too big. Or add a NFC sub-node for the NFC support.
IMHO, to make the NFC device as a sub-node is the simplest way to make
nand driver is back-compatible and easy to enable/disable NFC feature.
Since all NFC related property are grouped it is more readable.
But to implement this, I need to add this patch, otherwise this NFC sub
node will be recognized as a partition.
> Of course, we'd still have to retain
> backward-compatibility and allow partitions without a "compatible"
> prop. But this question probably should be addressed in the commit log
> and documented in Documentation/devicetree/bindings/mtd/partition.txt
> ; either specifying that all sub-nodes without a compatible property
> must be partitions, or else some other explanation.
yes, sure. I will add an explanation in commit log and
Documentation/devicetree/bindings/mtd/partition.txt in next version.
>
> Brian
Best Regards,
Josh Wu
next prev parent reply other threads:[~2013-06-13 3:38 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-10 10:26 [PATCH v3 0/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) support Josh Wu
2013-06-10 10:26 ` [PATCH 1/6] MTD: atmel_nand: use devm_xxx gpio kzalloc, gpio and ioremap Josh Wu
2013-06-10 10:26 ` [PATCH 2/6] mtd: atmel_nand: replace pmecc enable code with one function Josh Wu
2013-06-12 11:57 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-10 10:26 ` [PATCH 3/6] mtd: atmel_nand: add Nand Flash Controller (NFC) support Josh Wu
2013-06-10 13:22 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-13 1:59 ` Josh Wu
2013-06-10 10:26 ` [PATCH 4/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) read data via sram Josh Wu
2013-06-12 11:58 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-10 10:26 ` [PATCH 5/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) write " Josh Wu
2013-06-12 11:58 ` Jean-Christophe PLAGNIOL-VILLARD
2013-06-10 10:26 ` [PATCH 6/6] mtd: ofpart: add compatible check for child nodes Josh Wu
2013-06-10 12:35 ` Sergei Shtylyov
2013-06-13 3:42 ` Josh Wu
2013-06-13 13:13 ` Sergei Shtylyov
2013-06-11 23:34 ` Brian Norris
2013-06-13 3:38 ` Josh Wu [this message]
-- strict thread matches above, loose matches on Subject: below --
2013-06-19 6:23 [PATCH v4 0/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) support Josh Wu
2013-06-19 6:23 ` [PATCH 6/6] mtd: ofpart: add compatible check for child nodes Josh Wu
2013-07-03 9:50 [PATCH v5 0/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) support Josh Wu
2013-07-03 9:50 ` [PATCH 6/6] mtd: ofpart: add compatible check for child nodes Josh Wu
2013-07-18 7:14 ` Brian Norris
2013-07-18 8:28 ` Jean-Christophe PLAGNIOL-VILLARD
2013-08-05 11:14 [PATCH v6 0/6] mtd: atmel_nand: enable Nand Flash Controller (NFC) support Josh Wu
2013-08-05 11:14 ` [PATCH 6/6] mtd: ofpart: add compatible check for child nodes Josh Wu
2013-08-05 11:33 ` Josh Wu
2013-08-05 18:56 ` Brian Norris
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51B93EBF.5050207@atmel.com \
--to=josh.wu@atmel$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox