[RFC PATCH 13/16] mtd: nand: omap: True device tree support

[Roger Quadros]

The NAND controller must be a child node of the Chip select (CS) node.
NAND specific parameters are moved to the NAND node.

Move NAND specific device tree parsing to NAND driver.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
 arch/arm/mach-omap2/gpmc.c                   | 183 +++++++++++++--------------
 drivers/mtd/nand/omap2.c                     | 124 +++++++++++++++---
 include/linux/platform_data/mtd-nand-omap2.h |   6 +-
 3 files changed, 195 insertions(+), 118 deletions(-)

diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 132f786..6493010 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -27,9 +27,7 @@
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
-#include <linux/of_mtd.h>
 #include <linux/of_device.h>
-#include <linux/mtd/nand.h>
 #include <linux/pm_runtime.h>
 
 #include <linux/platform_data/mtd-nand-omap2.h>
@@ -40,7 +38,6 @@
 #include "common.h"
 #include "omap_device.h"
 #include "gpmc.h"
-#include "gpmc-nand.h"
 #include "gpmc-onenand.h"
 
 #define	DEVICE_NAME		"omap-gpmc"
@@ -1153,96 +1150,6 @@ static void __maybe_unused gpmc_read_timings_dt(struct device_node *np,
 		of_property_read_bool(np, "gpmc,time-para-granularity");
 }
 
-#if IS_ENABLED(CONFIG_MTD_NAND)
-
-static const char * const nand_xfer_types[] = {
-	[NAND_OMAP_PREFETCH_POLLED]		= "prefetch-polled",
-	[NAND_OMAP_POLLED]			= "polled",
-	[NAND_OMAP_PREFETCH_DMA]		= "prefetch-dma",
-	[NAND_OMAP_PREFETCH_IRQ]		= "prefetch-irq",
-};
-
-static int gpmc_probe_nand_child(struct platform_device *pdev,
-				 struct device_node *child)
-{
-	u32 val;
-	const char *s;
-	struct gpmc_timings gpmc_t;
-	struct omap_nand_platform_data *gpmc_nand_data;
-
-	if (of_property_read_u32(child, "reg", &val) < 0) {
-		dev_err(&pdev->dev, "%s has no 'reg' property\n",
-			child->full_name);
-		return -ENODEV;
-	}
-
-	gpmc_nand_data = devm_kzalloc(&pdev->dev, sizeof(*gpmc_nand_data),
-				      GFP_KERNEL);
-	if (!gpmc_nand_data)
-		return -ENOMEM;
-
-	gpmc_nand_data->cs = val;
-	gpmc_nand_data->of_node = child;
-
-	/* Detect availability of ELM module */
-	gpmc_nand_data->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
-	if (gpmc_nand_data->elm_of_node == NULL)
-		gpmc_nand_data->elm_of_node =
-					of_parse_phandle(child, "elm_id", 0);
-	if (gpmc_nand_data->elm_of_node == NULL)
-		pr_warn("%s: ti,elm-id property not found\n", __func__);
-
-	/* select ecc-scheme for NAND */
-	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
-		pr_err("%s: ti,nand-ecc-opt not found\n", __func__);
-		return -ENODEV;
-	}
-	if (!strcmp(s, "ham1") || !strcmp(s, "sw") ||
-		!strcmp(s, "hw") || !strcmp(s, "hw-romcode"))
-		gpmc_nand_data->ecc_opt =
-				OMAP_ECC_HAM1_CODE_HW;
-	else if (!strcmp(s, "bch4"))
-		if (gpmc_nand_data->elm_of_node)
-			gpmc_nand_data->ecc_opt =
-				OMAP_ECC_BCH4_CODE_HW;
-		else
-			gpmc_nand_data->ecc_opt =
-				OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
-	else if (!strcmp(s, "bch8"))
-		if (gpmc_nand_data->elm_of_node)
-			gpmc_nand_data->ecc_opt =
-				OMAP_ECC_BCH8_CODE_HW;
-		else
-			gpmc_nand_data->ecc_opt =
-				OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
-	else
-		pr_err("%s: ti,nand-ecc-opt invalid value\n", __func__);
-
-	/* select data transfer mode for NAND controller */
-	if (!of_property_read_string(child, "ti,nand-xfer-type", &s))
-		for (val = 0; val < ARRAY_SIZE(nand_xfer_types); val++)
-			if (!strcasecmp(s, nand_xfer_types[val])) {
-				gpmc_nand_data->xfer_type = val;
-				break;
-			}
-
-	val = of_get_nand_bus_width(child);
-	if (val == 16)
-		gpmc_nand_data->devsize = NAND_BUSWIDTH_16;
-
-	gpmc_read_timings_dt(child, &gpmc_t);
-	gpmc_nand_init(gpmc_nand_data, &gpmc_t);
-
-	return 0;
-}
-#else
-static int gpmc_probe_nand_child(struct platform_device *pdev,
-				 struct device_node *child)
-{
-	return 0;
-}
-#endif
-
 #if IS_ENABLED(CONFIG_MTD_ONENAND)
 static int gpmc_probe_onenand_child(struct platform_device *pdev,
 				 struct device_node *child)
@@ -1372,6 +1279,90 @@ err:
 	return ret;
 }
 
+static int gpmc_probe_child(struct platform_device *pdev,
+			    struct device_node *child)
+{
+	struct gpmc_settings gpmc_s;
+	struct gpmc_timings gpmc_t;
+	struct resource res;
+	unsigned long base;
+	int ret, cs;
+	struct device *dev = &pdev->dev;
+	const char *child_name = child->full_name;
+	u32 val;
+
+	if (of_property_read_u32(child, "gpmc,cs", &cs) < 0) {
+		dev_err(dev, "%s: has no 'gpmc,cs' property\n", child_name);
+		return -EINVAL;
+	}
+
+	if (of_address_to_resource(child, 0, &res) < 0) {
+		dev_err(dev, "%s: has malformed 'reg' property\n", child_name);
+		return -EINVAL;
+	}
+
+	ret = gpmc_cs_request(cs, resource_size(&res), &base);
+	if (ret < 0) {
+		dev_err(dev, "%s: cannot request GPMC CS %d\n", child_name, cs);
+		return ret;
+	}
+
+	ret = gpmc_cs_remap(cs, res.start);
+	if (ret < 0) {
+		dev_err(dev, "%s: cannot remap GPMC CS %d to %pa\n",
+			child_name, cs, (void *)res.start);
+		goto err;
+	}
+
+	gpmc_read_settings_dt(child, &gpmc_s);
+
+	ret = of_property_read_u32(child, "gpmc,device-width", &val);
+	if (ret) {
+		dev_err(dev, "%s: has no 'gpmc,device-width' property\n",
+			child_name);
+		goto err;
+	}
+
+	switch (val) {
+	case 1:
+		gpmc_s.device_width = GPMC_DEVWIDTH_8BIT;
+		break;
+	case 2:
+		gpmc_s.device_width = GPMC_DEVWIDTH_16BIT;
+		break;
+	default:
+		dev_err(dev, "%s: invalid 'gpmc,device-width'\n", child_name);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	gpmc_s.device_nand = of_property_read_bool(child, "gpmc,nand");
+
+	ret = gpmc_cs_program_settings(cs, &gpmc_s);
+	if (ret < 0) {
+		dev_err(dev, "%s: failed to program GPMC settings\n",
+			child_name);
+		goto err;
+	}
+
+	gpmc_read_timings_dt(child, &gpmc_t);
+	gpmc_cs_set_timings(cs, &gpmc_t);
+
+	ret = of_platform_populate(child, NULL, NULL, &pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to create gpmc child %s\n",
+			child_name);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	gpmc_cs_free(cs);
+
+	return ret;
+}
+
 static int gpmc_probe_dt(struct platform_device *pdev)
 {
 	int ret;
@@ -1408,14 +1399,14 @@ static int gpmc_probe_dt(struct platform_device *pdev)
 		if (!child->name)
 			continue;
 
-		if (of_node_cmp(child->name, "nand") == 0)
-			ret = gpmc_probe_nand_child(pdev, child);
-		else if (of_node_cmp(child->name, "onenand") == 0)
+		if (of_node_cmp(child->name, "onenand") == 0)
 			ret = gpmc_probe_onenand_child(pdev, child);
 		else if (of_node_cmp(child->name, "ethernet") == 0 ||
 			 of_node_cmp(child->name, "nor") == 0 ||
 			 of_node_cmp(child->name, "uart") == 0)
 			ret = gpmc_probe_generic_child(pdev, child);
+		else
+			ret = gpmc_probe_child(pdev, child);
 
 		if (WARN(ret < 0, "%s: probing gpmc child %s failed\n",
 			 __func__, child->full_name))
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 7ff5cb3..4ca1f48 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_mtd.h>
 
 #include <linux/mtd/nand_bch.h>
 #include <linux/platform_data/elm.h>
@@ -1676,10 +1677,81 @@ static void gpmc_update_nand_reg(struct omap_nand_info *info)
 	}
 }
 
+static const char * const nand_xfer_types[] = {
+	[NAND_OMAP_PREFETCH_POLLED] = "prefetch-polled",
+	[NAND_OMAP_POLLED] = "polled",
+	[NAND_OMAP_PREFETCH_DMA] = "prefetch-dma",
+	[NAND_OMAP_PREFETCH_IRQ] = "prefetch-irq",
+};
+
+static int omap_get_dt_info(struct device *dev, struct omap_nand_info *info)
+{
+	struct device_node *child = dev->of_node;
+	int i;
+	const char *s;
+
+	if (of_property_read_u32(child, "ti,nand-cs", &info->gpmc_cs)) {
+		dev_err(dev, "ti,nand-cs not found in DT\n");
+		return -EINVAL;
+	}
+
+	/* detect availability of ELM module. Won't be present pre-OMAP4 */
+	info->elm_of_node = of_parse_phandle(child, "ti,elm-id", 0);
+	if (info->elm_of_node == NULL)
+		dev_dbg(dev, "ti,elm-id not in DT\n");
+
+	/* select ecc-scheme */
+	if (of_property_read_string(child, "ti,nand-ecc-opt", &s)) {
+		/* default to HAM1 */
+		info->ecc_opt = OMAP_ECC_HAM1_CODE_HW;
+		goto ecc_done;
+	}
+
+	if (!strcmp(s, "ham1") || !strcmp(s, "sw") ||
+	    !strcmp(s, "hw") || !strcmp(s, "hw-romcode")) {
+		info->ecc_opt = OMAP_ECC_HAM1_CODE_HW;
+
+	} else if (!strcmp(s, "bch4")) {
+		if (info->elm_of_node)
+			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW;
+		else
+			info->ecc_opt = OMAP_ECC_BCH4_CODE_HW_DETECTION_SW;
+
+	} else if (!strcmp(s, "bch8")) {
+		if (info->elm_of_node)
+			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW;
+		else
+			info->ecc_opt = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
+	} else {
+		dev_err(dev, "unrecognized value for ti,nand-ecc-opt\n");
+		return -EINVAL;
+	}
+
+ecc_done:
+	/* select data transfer mode */
+	if (!of_property_read_string(child, "ti,nand-xfer-type", &s)) {
+		for (i = 0; i < ARRAY_SIZE(nand_xfer_types); i++) {
+			if (!strcasecmp(s, nand_xfer_types[i])) {
+				info->xfer_type = i;
+				goto found;
+			}
+		}
+
+		dev_err(dev, "unrecognized value for ti,nand-xfer-type\n");
+		return -EINVAL;
+	}
+
+found:
+	if (of_get_nand_bus_width(child) == 16)
+		info->devsize = NAND_BUSWIDTH_16;
+
+	return 0;
+}
+
 static int omap_nand_probe(struct platform_device *pdev)
 {
 	struct omap_nand_info *info;
-	struct omap_nand_platform_data *pdata;
+	struct omap_nand_platform_data *pdata = NULL;
 	struct mtd_info	*mtd;
 	struct nand_chip *nand_chip;
 	struct nand_ecclayout *ecclayout;
@@ -1692,31 +1764,37 @@ static int omap_nand_probe(struct platform_device *pdev)
 	struct mtd_part_parser_data ppdata = {};
 	struct device *dev = &pdev->dev;
 
-	pdata = dev_get_platdata(&pdev->dev);
-	if (pdata == NULL) {
-		dev_err(&pdev->dev, "platform data missing\n");
-		return -ENODEV;
-	}
 
 	info = devm_kzalloc(&pdev->dev, sizeof(struct omap_nand_info),
 				GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;
 
+	info->pdev = pdev;
+
+	if (dev->of_node) {
+		if (omap_get_dt_info(dev, info))
+			return -EINVAL;
+	} else {
+		pdata = dev_get_platdata(&pdev->dev);
+		if (pdata == NULL) {
+			dev_err(&pdev->dev, "platform data missing\n");
+			return -EINVAL;
+		}
+
+		info->gpmc_cs = pdata->cs;
+		info->of_node = pdata->of_node;
+		info->ecc_opt = pdata->ecc_opt;
+		info->dev_ready	= pdata->dev_ready;
+		info->xfer_type = pdata->xfer_type;
+		info->devsize = pdata->devsize;
+	}
+
 	platform_set_drvdata(pdev, info);
 
 	spin_lock_init(&info->controller.lock);
 	init_waitqueue_head(&info->controller.wq);
 
-	info->pdev		= pdev;
-	info->gpmc_cs		= pdata->cs;
-	info->of_node		= pdata->of_node;
-	info->ecc_opt		= pdata->ecc_opt;
-	info->dev_ready	= pdata->dev_ready;
-	info->xfer_type = pdata->xfer_type;
-	info->devsize = pdata->devsize;
-	info->elm_of_node = pdata->elm_of_node;
-
 	mtd			= &info->mtd;
 	mtd->priv		= &info->nand;
 	mtd->name		= dev_name(&pdev->dev);
@@ -2067,9 +2145,13 @@ static int omap_nand_probe(struct platform_device *pdev)
 		goto return_error;
 	}
 
-	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;
+		mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
+
+	} else {
+		mtd_device_register(mtd, pdata->parts, pdata->nr_parts);
+	}
 
 	platform_set_drvdata(pdev, mtd);
 
@@ -2101,12 +2183,18 @@ 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,
 		.owner	= THIS_MODULE,
+		.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 62a855e..45203a5 100644
--- a/include/linux/platform_data/mtd-nand-omap2.h
+++ b/include/linux/platform_data/mtd-nand-omap2.h
@@ -64,10 +64,8 @@ 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;
-
 	struct gpmc_nand_regs	reg;		/* deprecated */
+	struct device_node	*elm_of_node;	/* deprecated */
+	struct device_node	*of_node;	/* deprecated */
 };
 #endif
-- 
1.8.3.2

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