Re: [PATCH v4 11/27] mtd: nand: omap: Clean up device tree support

From: Roger Quadros
Date: Thu Dec 03 2015 - 00:58:18 EST


Brian,

On 03/12/15 09:59, Brian Norris wrote:
> Hi Roger,
>
> On Tue, Oct 06, 2015 at 01:35:48PM +0300, Roger Quadros wrote:
>> Move NAND specific device tree parsing to NAND driver.
>>
>> The NAND controller node must have a compatible id, register space
>> resource and interrupt resource.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>
> This one's going to need rebased, as there are some conflicting of_node
> changes in l2-mtd.git.

Al right. I'll rebase on top of l2-mtd.git
>
>> ---
>> v4: Warn if using older incompatible DT i.e. compatible property not present
>> in nand node.
>>
>> arch/arm/mach-omap2/gpmc-nand.c | 5 +-
>> drivers/memory/omap-gpmc.c | 143 +++++++--------------------
>> drivers/mtd/nand/omap2.c | 136 +++++++++++++++++++++----
>> include/linux/platform_data/mtd-nand-omap2.h | 3 +-
>> 4 files changed, 155 insertions(+), 132 deletions(-)
>
> Also, this is going to be hard to manage across trees, as you touch
> three drivers all at once. Is it not possible to split any of this apart
> better?

Will need some more effort and I can do it. Butm if we're going to start
an with immutable branch with everything in, is it worth the effort?
>
>>
>> diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c
>> index ffe646a..e07ca27 100644
>> --- a/arch/arm/mach-omap2/gpmc-nand.c
>> +++ b/arch/arm/mach-omap2/gpmc-nand.c
>> @@ -95,10 +95,7 @@ int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
>> gpmc_nand_res[1].start = gpmc_get_irq();
>>
>> memset(&s, 0, sizeof(struct gpmc_settings));
>> - if (gpmc_nand_data->of_node)
>> - gpmc_read_settings_dt(gpmc_nand_data->of_node, &s);
>> - else
>> - gpmc_set_legacy(gpmc_nand_data, &s);
>> + gpmc_set_legacy(gpmc_nand_data, &s);
>>
>> s.device_nand = true;
>>
>> diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
>> index e75226d..318c187 100644
>> --- a/drivers/memory/omap-gpmc.c
>> +++ b/drivers/memory/omap-gpmc.c
>> @@ -29,7 +29,6 @@
>> #include <linux/of_device.h>
>> #include <linux/of_platform.h>
>> #include <linux/omap-gpmc.h>
>> -#include <linux/mtd/nand.h>
>> #include <linux/pm_runtime.h>
>>

<snip>

>>
>> - ppdata.of_node = pdata->of_node;
>> - mtd_device_parse_register(mtd, NULL, &ppdata, pdata->parts,
>> - pdata->nr_parts);
>> + if (dev->of_node) {
>> + ppdata.of_node = dev->of_node;
>
> The latest l2-mtd.git changed how the partitions' of_node is passed. Now
> this is handled by nand_set_flash_node().

OK.
>
>> + mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
>> +
>> + } else {
>> + mtd_device_register(mtd, pdata->parts, pdata->nr_parts);
>> + }
>>
>> platform_set_drvdata(pdev, mtd);
>>
>> @@ -2083,11 +2173,17 @@ static int omap_nand_remove(struct platform_device *pdev)
>> return 0;
>> }
>>
>> +static const struct of_device_id omap_nand_ids[] = {
>> + { .compatible = "ti,omap2-nand", },
>> + {},
>> +};
>> +
>> static struct platform_driver omap_nand_driver = {
>> .probe = omap_nand_probe,
>> .remove = omap_nand_remove,
>> .driver = {
>> .name = DRIVER_NAME,
>> + .of_match_table = of_match_ptr(omap_nand_ids),
>> },
>> };
>>
>> diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
>> index a067f58..ff27e5a 100644
>> --- a/include/linux/platform_data/mtd-nand-omap2.h
>> +++ b/include/linux/platform_data/mtd-nand-omap2.h
>> @@ -76,11 +76,10 @@ struct omap_nand_platform_data {
>> int devsize;
>> enum omap_ecc ecc_opt;
>>
>> - /* for passing the partitions */
>> - struct device_node *of_node;
>> struct device_node *elm_of_node;
>>
>> /* deprecated */
>> struct gpmc_nand_regs reg;
>> + struct device_node *of_node;
>
> I'm a little confused here. Do you have a mixed platform data / device
> tree setup here? That's odd. (It also seems if that was really
> necessary, you could have the board file set pdev->dev.of_node before
> registering it, then you don't need this field.) But really, if you're
> partly using device tree, can't you just convert completely? Or is this
> a two-phase process, and you're planning to convert omap2 to full device
> tree?

The existing device tree implementation for omap2-nand was like this:
omap-gpmc.c driver was creating a platform device for the nand device and
passing the device node via platform data.

After this series we no longer do this and that's why of_node is marked
deprecated in platform data. I might as well could just get rid of it
but wasn't sure of how we're going to integrate the changes into the
subsystem trees so just marked it deprecated.

cheers,
-roger
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