On 20/12/2021 12:51, Roger Quadros wrote:

On 20/12/2021 13:05, Krzysztof Kozlowski wrote:

quoted

On 20/12/2021 11:53, Roger Quadros wrote:

quoted

On 17/12/2021 17:21, Krzysztof Kozlowski wrote:

quoted

On 17/12/2021 11:29, Roger Quadros wrote:

quoted

As more compatibles can be added to the GPMC NAND controller driver
use a compatible match table.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/memory/omap-gpmc.c                   | 8 +++++++-
 drivers/mtd/nand/raw/omap2.c                 | 2 +-
 include/linux/platform_data/mtd-nand-omap2.h | 5 +++++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index 624153048182..814ddb45c13d 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c

@@ -2091,6 +2091,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 	u32 val;
 	struct gpio_desc *waitpin_desc = NULL;
 	struct gpmc_device *gpmc = platform_get_drvdata(pdev);
+	bool is_nand = false;
 
 	if (of_property_read_u32(child, "reg", &cs) < 0) {
 		dev_err(&pdev->dev, "%pOF has no 'reg' property\n",

@@ -2183,7 +2184,12 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 		}
 	}
 
-	if (of_device_is_compatible(child, "ti,omap2-nand")) {
+#if defined(CONFIG_MTD_NAND_OMAP2)

if (IS_ENABLED()) is preferred. If needed, you could make omap_nand_ids
symbol visible always (so without ifdef around it), because extern
structure should not have impact when not defined (if I recall
correctly...).

quoted

+	if (of_match_node(omap_nand_ids, child))
+		is_nand = true;
+#endif
+
+	if (is_nand) {
 		/* NAND specific setup */
 		val = 8;
 		of_property_read_u32(child, "nand-bus-width", &val);

diff --git a/drivers/mtd/nand/raw/omap2.c b/drivers/mtd/nand/raw/omap2.c
index b26d4947af02..fff834ee726f 100644
--- a/drivers/mtd/nand/raw/omap2.c
+++ b/drivers/mtd/nand/raw/omap2.c

@@ -2352,7 +2352,7 @@ static int omap_nand_remove(struct platform_device *pdev)
 	return ret;
 }
 
-static const struct of_device_id omap_nand_ids[] = {
+const struct of_device_id omap_nand_ids[] = {
 	{ .compatible = "ti,omap2-nand", },
 	{},
 };

I think OMAP2 NAND driver can be a module, so this should have
EXPORT_SYMBOL.

To make it work in all combinations (e.g. omap_gpmc built in and
nand/raw/omap2.c as module) I had to define omap_nand_ids table as static
in the linux/platform_data/mtd-nand-omap2.h header.

EXPORT_SYMBOL will of course be not required there. ;)

Which case exactly does it require to be static in the header?

Maybe there is a better way to do it.
e.g. If omap_gpmc.c is built-in and nand/raw/omap2.c is not built or built as
a module, what better way we can use?

Ah, you are right, that is the tricky configuration. It could be a
separate built-in source file which is being selected by OMAP_GPMC and
MTD_NAND_OMAP2, but it would be also an overkill for one-item array.

I guess your solution with header is the easiest.


Best regards,
Krzysztof