Re: [PATCH v4 1/7] ARM: OMAP2+: gpmc-nand: Set omap2-nand's parent dev to GPMC dev

Franklin S Cooper Jr.
2016-03-11T15:39:28Z

On 03/11/2016 07:52 AM, Roger Quadros wrote:
> Franklin,
>
> On 11/03/16 01:56, Franklin S Cooper Jr wrote:
>> The dma channel information is located within the GPMC node which is the
>> NAND's parent node. The NAND driver requires a handle to the GPMC's dev
>> to properly parse the DMA properties. Therefore, set the NAND's parent dev
>> to the GPMC's dev so it can be referenced within the driver.
>>
>> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
>> ---
>> Version 4 changes:
>> Instead of storing the GPMC dev in a new property simply grab a reference
>> to it and set omap2-nand's dev.parent to it.
>>
>> arch/arm/mach-omap2/gpmc-nand.c | 16 +++++++++++++++-
>> 1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c
>> index 72918c4..77e453c 100644
>> --- a/arch/arm/mach-omap2/gpmc-nand.c
>> +++ b/arch/arm/mach-omap2/gpmc-nand.c
>> @@ -15,6 +15,7 @@
>> #include <linux/omap-gpmc.h>
>> #include <linux/mtd/nand.h>
>> #include <linux/platform_data/mtd-nand-omap2.h>
>> +#include <linux/of_platform.h>
>>
>> #include <asm/mach/flash.h>
>>
>> @@ -77,6 +78,9 @@ int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
>> int err = 0;
>> struct gpmc_settings s;
>> struct platform_device *pdev;
>> + struct platform_device *gpmc_dev;
>> + struct device_node *gpmc_node;
>> +
>> struct resource gpmc_nand_res[] = {
>> { .flags = IORESOURCE_MEM, },
>> { .flags = IORESOURCE_IRQ, },
>> @@ -134,8 +138,18 @@ int gpmc_nand_init(struct omap_nand_platform_data *gpmc_nand_data,
>> if (pdev) {
>> err = platform_device_add_resources(pdev, gpmc_nand_res,
>> ARRAY_SIZE(gpmc_nand_res));
>> - if (!err)
>> + if (!err) {
>> pdev->dev.platform_data = gpmc_nand_data;
>> +
>> + gpmc_node = of_get_parent(gpmc_nand_data->of_node);
> I'm afraid that we can't use this method as we want to restrict
> gpmc_nand_init() to non-DT boots.

The only users of the parent GPMC driver are already using
DT. The gpmc_probe_nand_child function in the GPMC driver
which calls gpmc_nand_init is already DT only.

The only other caller to gpmc_nand_init is board-flash.c.
The driver doesn't utilize xfer_type to even switch to any
other modes including DMA prefetch mode. Looking at it
closer there isn't a dev from some kind of parent for me to
pass along. Board_nand_init which calls gpmc_nand_init just
takes raw NAND values with no relation to its parent.

With that being said are you ok with leaving it as is?
>
>> +
>> + if (gpmc_node) {
>> + gpmc_dev = of_find_device_by_node(gpmc_node);
>> +
>> + if (gpmc_dev)
>> + pdev->dev.parent = &gpmc_dev->dev;
>> + }
>> + }
>> } else {
>> err = -ENOMEM;
>> }
>>
> cheers,
> -roger