[u-boot][PATCH v2 4/8] mtd: rawnand: omap_gpmc: support u-boot driver model

[Roger Quadros <rogerq@kernel.org>]

Adds driver model support.

We need to be able to self initialize the NAND controller/chip
at probe and so enable CONFIG_SYS_NAND_SELF_INIT.

Doing so requires nand_register() API which is provided by nand.c
and needs to be enabled during SPL build via CONFIG_SPL_NAND_INIT.
But nand.c also provides nand_init() so we need to get rid of nand_init()
in omap_gpmc driver if CONFIG_SPL_NAND_INIT is set.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/mtd/nand/raw/Kconfig     |  1 +
 drivers/mtd/nand/raw/omap_gpmc.c | 64 +++++++++++++++++++++++++++++++-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index 8aaba8b1a2c..3f4851b93bd 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -198,6 +198,7 @@ config NAND_LPC32XX_SLC
 config NAND_OMAP_GPMC
 	bool "Support OMAP GPMC NAND controller"
 	depends on ARCH_OMAP2PLUS || ARCH_KEYSTONE || ARCH_K3
+	select SYS_NAND_SELF_INIT if ARCH_K3
 	help
 	  Enables omap_gpmc.c driver for OMAPx and AMxxxx platforms.
 	  GPMC controller is used for parallel NAND flash devices, and can
diff --git a/drivers/mtd/nand/raw/omap_gpmc.c b/drivers/mtd/nand/raw/omap_gpmc.c
index e772a914c88..61e025db9a5 100644
--- a/drivers/mtd/nand/raw/omap_gpmc.c
+++ b/drivers/mtd/nand/raw/omap_gpmc.c
@@ -7,6 +7,7 @@
 #include <common.h>
 #include <log.h>
 #include <asm/io.h>
+#include <dm/uclass.h>
 #include <linux/errno.h>
 
 #ifdef CONFIG_ARCH_OMAP2PLUS
@@ -1121,7 +1122,7 @@ int __maybe_unused omap_nand_switch_ecc(uint32_t hardware, uint32_t eccstrength)
  *   nand_scan about special functionality. See the defines for further
  *   explanation
  */
-int board_nand_init(struct nand_chip *nand)
+int gpmc_nand_init(struct nand_chip *nand)
 {
 	int32_t gpmc_config = 0;
 	int cs = cs_next++;
@@ -1201,3 +1202,64 @@ int board_nand_init(struct nand_chip *nand)
 
 	return 0;
 }
+
+/* First NAND chip for SPL use only */
+static __maybe_unused struct nand_chip *nand_chip;
+
+#if CONFIG_IS_ENABLED(SYS_NAND_SELF_INIT)
+
+static int gpmc_nand_probe(struct udevice *dev)
+{
+	struct nand_chip *nand = dev_get_priv(dev);
+	struct mtd_info *mtd = nand_to_mtd(nand);
+	int ret;
+
+	gpmc_nand_init(nand);
+
+	ret = nand_scan(mtd, CONFIG_SYS_NAND_MAX_CHIPS);
+	if (ret)
+		return ret;
+
+	ret = nand_register(0, mtd);
+	if (ret)
+		return ret;
+
+	if (!nand_chip)
+		nand_chip = nand;
+
+	return 0;
+}
+
+static const struct udevice_id gpmc_nand_ids[] = {
+	{ .compatible = "ti,am64-nand" },
+	{ .compatible = "ti,omap2-nand" },
+	{ }
+};
+
+U_BOOT_DRIVER(gpmc_nand) = {
+	.name           = "gpmc-nand",
+	.id             = UCLASS_MTD,
+	.of_match       = gpmc_nand_ids,
+	.probe          = gpmc_nand_probe,
+	.priv_auto	= sizeof(struct nand_chip),
+};
+
+void board_nand_init(void)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_MTD,
+					  DM_DRIVER_GET(gpmc_nand), &dev);
+	if (ret && ret != -ENODEV)
+		pr_err("%s: Failed to get GPMC device: %d\n", __func__, ret);
+}
+
+#else
+
+int board_nand_init(struct nand_chip *nand)
+{
+	return gpmc_nand_init(nand);
+}
+
+#endif /* CONFIG_SYS_NAND_SELF_INIT */
-- 
2.34.1