[PATCH] mtd: nand-omap2: Move omap_nand_ids[] to raw nand driver

[Uwe Kleine-König (The Capable Hub)]

Defining a static array in a header results in each .c file that
includes the header (here: drivers/memory/omap-gpmc.c and
drivers/mtd/nand/raw/omap2.c) to contain a copy of that array when
compiled to an object file.

With sizeof(struct of_device_id[3]) ≥ 588 having omap_nand_ids[] twice
just to do two string comparisons is quite some bloat. So move
omap_nand_ids[] to the nand driver which actually needs that array for
its module meta data and do the compatible check by hand.

bloat-o-meter reports for drivers/memory/omap-gpmc.o (ARCH=arm):

	add/remove: 1/2 grow/shrink: 1/0 up/down: 28/-588 (-560)
	Function                                     old     new   delta
	gpmc_probe_generic_child                    2108    2136     +28
	omap_nand_ids                                588       -    -588
	Total: Before=18114, After=17554, chg -3.09%

(drivers/mtd/nand/raw/omap2.o doesn't change).

This allows to drop <linux/mod_devicetable.h> from
include/linux/platform_data/mtd-nand-omap2.h (which is my original
motivation for this change). Note that this header isn't needed in the
two drivers because omap-gpmc.c doesn't use any device id struct and for
the nand driver omap2.c of_device_id is already provided via
<linux/platform_device.h>.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@xxxxxxxxxxxx>
---
 drivers/memory/omap-gpmc.c                   | 9 ++++++++-
 drivers/mtd/nand/raw/omap2.c                 | 6 +++++-
 include/linux/platform_data/mtd-nand-omap2.h | 7 -------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index 958d2b0ea54a..48af31a54b55 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -2129,6 +2129,13 @@ static void __maybe_unused gpmc_read_timings_dt(struct device_node *np,
 		of_property_read_bool(np, "gpmc,time-para-granularity");
 }
 
+static int gpmc_child_is_nand(struct device_node *child)
+{
+	/* This has to match drivers/mtd/nand/raw/omap2.c's omap_nand_ids[] */
+	return of_device_is_compatible(child, "ti,omap2-nand") ||
+		of_device_is_compatible(child, "ti,am64-nand");
+}
+
 /**
  * gpmc_probe_generic_child - configures the gpmc for a child device
  * @pdev:	pointer to gpmc platform device
@@ -2220,7 +2227,7 @@ static int gpmc_probe_generic_child(struct platform_device *pdev,
 		goto err;
 	}
 
-	if (of_match_node(omap_nand_ids, child)) {
+	if (gpmc_child_is_nand(child)) {
 		/* 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 39e297486721..552f36da79fc 100644
--- a/drivers/mtd/nand/raw/omap2.c
+++ b/drivers/mtd/nand/raw/omap2.c
@@ -2318,7 +2318,11 @@ static void omap_nand_remove(struct platform_device *pdev)
 	nand_cleanup(nand_chip);
 }
 
-/* omap_nand_ids defined in linux/platform_data/mtd-nand-omap2.h */
+static const struct of_device_id omap_nand_ids[] = {
+        { .compatible = "ti,omap2-nand" },
+        { .compatible = "ti,am64-nand" },
+        { }
+};
 MODULE_DEVICE_TABLE(of, omap_nand_ids);
 
 static struct platform_driver omap_nand_driver = {
diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
index 8c2f1f185353..2ddb624b97fd 100644
--- a/include/linux/platform_data/mtd-nand-omap2.h
+++ b/include/linux/platform_data/mtd-nand-omap2.h
@@ -7,7 +7,6 @@
 #define	_MTD_NAND_OMAP2_H
 
 #include <linux/mtd/partitions.h>
-#include <linux/mod_devicetable.h>
 
 #define	GPMC_BCH_NUM_REMAINDER	8
 
@@ -63,10 +62,4 @@ struct gpmc_nand_regs {
 	void __iomem	*gpmc_bch_result6[GPMC_BCH_NUM_REMAINDER];
 };
 
-static const struct of_device_id omap_nand_ids[] = {
-	{ .compatible = "ti,omap2-nand", },
-	{ .compatible = "ti,am64-nand", },
-	{},
-};
-
 #endif /* _MTD_NAND_OMAP2_H */

base-commit: 1a1757b76427f6201bfe0bf1bea9f7574f332a93
-- 
2.55.0.11.g153666a7d9bb