[PATCH v3 1/4] mtd: nand: gpio: Add DT property to automatically determine bus width

[PATCH v3 1/4] mtd: nand: gpio: Add DT property to automatically determine bus width

[Alexander Shiyan]

This patch adds a property to automatically determine the NAND
bus width. This property works if the bus width is not specified
explicitly.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 .../devicetree/bindings/mtd/gpio-control-nand.txt        |  2 ++
 drivers/mtd/nand/gpio.c                                  | 16 ++++++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
index 36ef07d..91070d0 100644
--- a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
@@ -19,6 +19,8 @@ Optional properties:
   defaults to 1 byte.
 - chip-delay : chip dependent delay for transferring data from array to
   read registers (tR).  If not present then a default of 20us is used.
+- gpio-control-nand,bank-width-auto : Device bus width is determined
+  automatically if "bank-width" is omitted (Boolean).
 - gpio-control-nand,io-sync-reg : A 64-bit physical address for a read
   location used to guard against bus reordering with regards to accesses to
   the GPIO's and the NAND flash data bus.  If present, then after changing
diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
index 800a1cc..c75f92e 100644
--- a/drivers/mtd/nand/gpio.c
+++ b/drivers/mtd/nand/gpio.c
@@ -116,6 +116,10 @@ static int gpio_nand_get_config_of(const struct device *dev,
 			dev_err(dev, "invalid bank-width %u\n", val);
 			return -EINVAL;
 		}
+	} else {
+		if (of_get_property(dev->of_node,
+				    "gpio-control-nand,bank-width-auto", NULL))
+			plat->options |= NAND_BUSWIDTH_AUTO;
 	}
 
 	plat->gpio_rdy = of_get_gpio(dev->of_node, 0);
@@ -223,6 +227,14 @@ static int gpio_nand_probe(struct platform_device *pdev)
 	if (IS_ERR(chip->IO_ADDR_R))
 		return PTR_ERR(chip->IO_ADDR_R);
 
+	ret = gpio_nand_get_config(&pdev->dev, &gpiomtd->plat);
+	if (ret)
+		return ret;
+
+	if (resource_size(res) < 2)
+		gpiomtd->plat.options &= ~(NAND_BUSWIDTH_16 |
+					   NAND_BUSWIDTH_AUTO);
+
 	res = gpio_nand_get_io_sync(pdev);
 	if (res) {
 		gpiomtd->io_sync = devm_ioremap_resource(&pdev->dev, res);
@@ -230,10 +242,6 @@ static int gpio_nand_probe(struct platform_device *pdev)
 			return PTR_ERR(gpiomtd->io_sync);
 	}
 
-	ret = gpio_nand_get_config(&pdev->dev, &gpiomtd->plat);
-	if (ret)
-		return ret;
-
 	ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce, "NAND NCE");
 	if (ret)
 		return ret;
-- 
1.8.1.5

[PATCH v3 4/4] mtd: nand: gpio: Add support for multichip devices

[Alexander Shiyan]

This patch adds support for multichip NAND devices controlled through GPIOs.
To implement this, the properties of tree have been renamed. All current
boards and DTS files converted to use an updated driver. Also driver
temporarily keep support for DTS files which use the previous names scheme.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 .../devicetree/bindings/mtd/gpio-control-nand.txt  |  16 +--
 arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts       |  10 +-
 arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts       |  10 +-
 arch/arm/mach-clps711x/board-autcpu12.c            |   4 +-
 arch/arm/mach-clps711x/board-p720t.c               |   4 +-
 arch/arm/mach-pxa/cm-x255.c                        |  10 +-
 drivers/mtd/nand/gpio.c                            | 108 +++++++++++++++------
 include/linux/mtd/nand-gpio.h                      |  12 ++-
 8 files changed, 112 insertions(+), 62 deletions(-)

diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
index 91070d0..c58210a 100644
--- a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
@@ -11,8 +11,11 @@ Required properties:
   are made in native endianness.
 - #address-cells, #size-cells : Must be present if the device has sub-nodes
   representing partitions.
-- gpios : specifies the gpio pins to control the NAND device.  nwp is an
-  optional gpio and may be set to 0 if not present.
+- ale-gpios : specifies the ALE gpio pin.
+- cle-gpios : specifies the CLE gpio pin.
+- nwp-gpios : specifies the NWP gpio pin (Optional).
+- nce-gpios : specifies the NCE gpio pin or several NCE GPIOs for multichip NAND.
+- rdy-gpios : specifies the RDY gpio pin or several RDY GPIOs for multichip NAND.
 
 Optional properties:
 - bank-width : Width (in bytes) of the device.  If not present, the width
@@ -37,11 +40,10 @@ gpio-nand@1,0 {
 	reg = <1 0x0000 0x2>;
 	#address-cells = <1>;
 	#size-cells = <1>;
-	gpios = <&banka 1 0	/* rdy */
-		 &banka 2 0 	/* nce */
-		 &banka 3 0 	/* ale */
-		 &banka 4 0 	/* cle */
-		 0		/* nwp */>;
+	ale-gpios = <&banka 3 0>;
+	cle-gpios = <&banka 4 0>;
+	nce-gpios = <&banka 2 0>;
+	rdy-gpios = <&banka 1 0>;
 
 	partition@0 {
 	...
diff --git a/arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts b/arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts
index 1297414d..709eed6 100644
--- a/arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts
+++ b/arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts
@@ -44,12 +44,10 @@
 				bus-clock = <&pclk>, "bus";
 				gpio-control-nand,io-sync-reg =
 					<0x00000000 0x80220000>;
-
-				gpios = <&banka 1 0	/* rdy */
-					 &banka 2 0 	/* nce */
-					 &banka 3 0 	/* ale */
-					 &banka 4 0 	/* cle */
-					 0		/* nwp */>;
+				ale-gpios = <&banka 3 0>;
+				cle-gpios = <&banka 4 0>;
+				nce-gpios = <&banka 2 0>;
+				rdy-gpios = <&banka 1 0>;
 
 				boot@100000 {
 					label = "Boot";
diff --git a/arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts b/arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts
index 9e317a4..1438f9f 100644
--- a/arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts
+++ b/arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts
@@ -50,12 +50,10 @@
 				bus-clock = <&ebi_clk>, "bus";
 				gpio-control-nand,io-sync-reg =
 					<0x00000000 0x80220000>;
-
-				gpios = <&banka 1 0	/* rdy */
-					 &banka 2 0 	/* nce */
-					 &banka 3 0 	/* ale */
-					 &banka 4 0 	/* cle */
-					 0		/* nwp */>;
+				ale-gpios = <&banka 3 0>;
+				cle-gpios = <&banka 4 0>;
+				nce-gpios = <&banka 2 0>;
+				rdy-gpios = <&banka 1 0>;
 
 				boot@100000 {
 					label = "Boot";
diff --git a/arch/arm/mach-clps711x/board-autcpu12.c b/arch/arm/mach-clps711x/board-autcpu12.c
index 5867aeb..c1fa4bd 100644
--- a/arch/arm/mach-clps711x/board-autcpu12.c
+++ b/arch/arm/mach-clps711x/board-autcpu12.c
@@ -120,8 +120,8 @@ static void __init autcpu12_adjust_parts(struct gpio_nand_platdata *pdata,
 }
 
 static struct gpio_nand_platdata autcpu12_nand_pdata __initdata = {
-	.gpio_rdy	= AUTCPU12_SMC_RDY,
-	.gpio_nce	= AUTCPU12_SMC_NCE,
+	.gpio_rdy[0]	= AUTCPU12_SMC_RDY,
+	.gpio_nce[0]	= AUTCPU12_SMC_NCE,
 	.gpio_ale	= AUTCPU12_SMC_ALE,
 	.gpio_cle	= AUTCPU12_SMC_CLE,
 	.gpio_nwp	= -1,
diff --git a/arch/arm/mach-clps711x/board-p720t.c b/arch/arm/mach-clps711x/board-p720t.c
index dd81b06..3774417 100644
--- a/arch/arm/mach-clps711x/board-p720t.c
+++ b/arch/arm/mach-clps711x/board-p720t.c
@@ -243,8 +243,8 @@ static struct mtd_partition p720t_nand_parts[] __initdata = {
 };
 
 static struct gpio_nand_platdata p720t_nand_pdata __initdata = {
-	.gpio_rdy	= -1,
-	.gpio_nce	= P720T_NAND_NCE,
+	.gpio_rdy[0]	= -1,
+	.gpio_nce[0]	= P720T_NAND_NCE,
 	.gpio_ale	= P720T_NAND_ALE,
 	.gpio_cle	= P720T_NAND_CLE,
 	.gpio_nwp	= -1,
diff --git a/arch/arm/mach-pxa/cm-x255.c b/arch/arm/mach-pxa/cm-x255.c
index be75147..3cb9f4d 100644
--- a/arch/arm/mach-pxa/cm-x255.c
+++ b/arch/arm/mach-pxa/cm-x255.c
@@ -198,11 +198,11 @@ static struct mtd_partition cmx255_nand_parts[] = {
 };
 
 static struct gpio_nand_platdata cmx255_nand_platdata = {
-	.gpio_nce = GPIO_NAND_CS,
-	.gpio_cle = GPIO_NAND_CLE,
-	.gpio_ale = GPIO_NAND_ALE,
-	.gpio_rdy = GPIO_NAND_RB,
-	.gpio_nwp = -1,
+	.gpio_nce[0]	= GPIO_NAND_CS,
+	.gpio_cle	= GPIO_NAND_CLE,
+	.gpio_ale	= GPIO_NAND_ALE,
+	.gpio_rdy[0]	= GPIO_NAND_RB,
+	.gpio_nwp	= -1,
 	.parts = cmx255_nand_parts,
 	.num_parts = ARRAY_SIZE(cmx255_nand_parts),
 	.chip_delay = 25,
diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
index d4c123e..c33fde5 100644
--- a/drivers/mtd/nand/gpio.c
+++ b/drivers/mtd/nand/gpio.c
@@ -36,6 +36,7 @@ struct gpiomtd {
 	void __iomem		*io_sync;
 	struct mtd_info		mtd_info;
 	struct nand_chip	nand_chip;
+	int			chip_index;
 	struct gpio_nand_platdata plat;
 };
 
@@ -75,7 +76,8 @@ static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 	gpio_nand_dosync(gpiomtd);
 
 	if (ctrl & NAND_CTRL_CHANGE) {
-		gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
+		gpio_set_value(gpiomtd->plat.gpio_nce[gpiomtd->chip_index],
+			       !(ctrl & NAND_NCE));
 		gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
 		gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
 		gpio_nand_dosync(gpiomtd);
@@ -90,8 +92,26 @@ static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 static int gpio_nand_devready(struct mtd_info *mtd)
 {
 	struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
+	int idx = gpiomtd->chip_index;
 
-	return gpio_get_value(gpiomtd->plat.gpio_rdy);
+	if (!gpio_is_valid(gpiomtd->plat.gpio_rdy[idx]))
+		idx = 0;
+
+	return gpio_get_value(gpiomtd->plat.gpio_rdy[idx]);
+}
+
+static void gpio_nand_select_chip(struct mtd_info *mtd, int chipnr)
+{
+	struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
+
+	switch (chipnr) {
+	case -1:
+		gpio_nand_cmd_ctrl(mtd, NAND_CMD_NONE, 0 | NAND_CTRL_CHANGE);
+		break;
+	default:
+		gpiomtd->chip_index = chipnr;
+		break;
+	}
 }
 
 #ifdef CONFIG_OF
@@ -104,12 +124,14 @@ MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
 static int gpio_nand_get_config_of(const struct device *dev,
 				   struct gpio_nand_platdata *plat)
 {
+	struct device_node *np = dev->of_node;
 	u32 val;
+	int i;
 
 	if (!dev->of_node)
 		return -ENODEV;
 
-	if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
+	if (!of_property_read_u32(np, "bank-width", &val)) {
 		if (val == 2) {
 			plat->options |= NAND_BUSWIDTH_16;
 		} else if (val != 1) {
@@ -117,18 +139,33 @@ static int gpio_nand_get_config_of(const struct device *dev,
 			return -EINVAL;
 		}
 	} else {
-		if (of_get_property(dev->of_node,
+		if (of_get_property(np,
 				    "gpio-control-nand,bank-width-auto", NULL))
 			plat->options |= NAND_BUSWIDTH_AUTO;
 	}
 
-	plat->gpio_rdy = of_get_gpio(dev->of_node, 0);
-	plat->gpio_nce = of_get_gpio(dev->of_node, 1);
-	plat->gpio_ale = of_get_gpio(dev->of_node, 2);
-	plat->gpio_cle = of_get_gpio(dev->of_node, 3);
-	plat->gpio_nwp = of_get_gpio(dev->of_node, 4);
+	if (of_find_property(np, "gpios", NULL)) {
+		dev_notice(dev, "Property \"gpios\" is deprecated");
 
-	if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
+		plat->gpio_rdy[0] = of_get_gpio(np, 0);
+		plat->gpio_nce[0] = of_get_gpio(np, 1);
+		plat->gpio_ale = of_get_gpio(np, 2);
+		plat->gpio_cle = of_get_gpio(np, 3);
+		plat->gpio_nwp = of_get_gpio(np, 4);
+	} else {
+		plat->gpio_ale = of_get_named_gpio(np, "ale-gpios", 0);
+		plat->gpio_cle = of_get_named_gpio(np, "cle-gpios", 0);
+		plat->gpio_nwp = of_get_named_gpio(np, "nwp-gpios", 0);
+
+		for (i = 0; i < MAX_NAND_PER_CHIP; i++) {
+			plat->gpio_nce[i] = of_get_named_gpio(np,
+							      "nce-gpios", i);
+			plat->gpio_rdy[i] = of_get_named_gpio(np,
+							      "rdy-gpios", i);
+		}
+	}
+
+	if (!of_property_read_u32(np, "chip-delay", &val))
 		plat->chip_delay = val;
 
 	return 0;
@@ -199,12 +236,15 @@ static void gpio_nand_set_wp(struct gpiomtd *gpiomtd, int val)
 static int gpio_nand_remove(struct platform_device *pdev)
 {
 	struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
+	int i;
 
 	nand_release(&gpiomtd->mtd_info);
 
 	gpio_nand_set_wp(gpiomtd, 0);
 
-	gpio_set_value(gpiomtd->plat.gpio_nce, 1);
+	for (i = 0; i < MAX_NAND_PER_CHIP; i++)
+		if (gpio_is_valid(gpiomtd->plat.gpio_nce[i]))
+			gpio_set_value(gpiomtd->plat.gpio_nce[i], 1);
 
 	return 0;
 }
@@ -215,7 +255,7 @@ static int gpio_nand_probe(struct platform_device *pdev)
 	struct nand_chip *chip;
 	struct resource *res;
 	struct mtd_part_parser_data ppdata = {};
-	int ret;
+	int i, ret, found = 0;
 
 	if (!pdev->dev.of_node && !pdev->dev.platform_data)
 		return -EINVAL;
@@ -248,18 +288,6 @@ static int gpio_nand_probe(struct platform_device *pdev)
 			return PTR_ERR(gpiomtd->io_sync);
 	}
 
-	ret = devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_nce,
-				    GPIOF_OUT_INIT_HIGH, "NAND NCE");
-	if (ret)
-		return ret;
-
-	if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
-		ret = devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_nwp,
-					    GPIOF_OUT_INIT_LOW, "NAND NWP");
-		if (ret)
-			return ret;
-	}
-
 	ret = devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_ale,
 				    GPIOF_OUT_INIT_LOW, "NAND ALE");
 	if (ret)
@@ -270,19 +298,41 @@ static int gpio_nand_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	if (gpio_is_valid(gpiomtd->plat.gpio_rdy)) {
-		ret = devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_rdy,
-					    GPIOF_IN, "NAND RDY");
+	if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
+		ret = devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_nwp,
+					    GPIOF_OUT_INIT_LOW, "NAND NWP");
 		if (ret)
 			return ret;
-		chip->dev_ready = gpio_nand_devready;
 	}
 
+	for (i = 0; i < MAX_NAND_PER_CHIP; i++) {
+		if (!gpio_is_valid(gpiomtd->plat.gpio_nce[i]))
+			break;
+		if (devm_gpio_request_one(&pdev->dev, gpiomtd->plat.gpio_nce[i],
+					  GPIOF_OUT_INIT_HIGH, NULL))
+			break;
+
+		found++;
+
+		if (gpio_is_valid(gpiomtd->plat.gpio_rdy[i])) {
+			if (devm_gpio_request_one(&pdev->dev,
+						  gpiomtd->plat.gpio_rdy[i],
+						  GPIOF_IN, NULL))
+				gpiomtd->plat.gpio_rdy[i] = -1;
+			else if (!i)
+				chip->dev_ready = gpio_nand_devready;
+		}
+	}
+
+	if (!found)
+		return -EINVAL;
+
 	chip->IO_ADDR_W		= chip->IO_ADDR_R;
 	chip->ecc.mode		= NAND_ECC_SOFT;
 	chip->options		= gpiomtd->plat.options;
 	chip->chip_delay	= gpiomtd->plat.chip_delay;
 	chip->cmd_ctrl		= gpio_nand_cmd_ctrl;
+	chip->select_chip	= gpio_nand_select_chip;
 
 	gpiomtd->mtd_info.priv	= chip;
 	gpiomtd->mtd_info.owner	= THIS_MODULE;
@@ -291,7 +341,7 @@ static int gpio_nand_probe(struct platform_device *pdev)
 
 	gpio_nand_set_wp(gpiomtd, 1);
 
-	ret = nand_scan(&gpiomtd->mtd_info, 1);
+	ret = nand_scan(&gpiomtd->mtd_info, found);
 	if (ret)
 		goto err_wp;
 
diff --git a/include/linux/mtd/nand-gpio.h b/include/linux/mtd/nand-gpio.h
index 51534e5..bb1d7e7 100644
--- a/include/linux/mtd/nand-gpio.h
+++ b/include/linux/mtd/nand-gpio.h
@@ -3,12 +3,14 @@
 
 #include <linux/mtd/nand.h>
 
+#define MAX_NAND_PER_CHIP	4
+
 struct gpio_nand_platdata {
-	int	gpio_nce;
-	int	gpio_nwp;
-	int	gpio_cle;
-	int	gpio_ale;
-	int	gpio_rdy;
+	int	gpio_ale;			/* ALE */
+	int	gpio_cle;			/* CLE */
+	int	gpio_nwp;			/* NWP (Optional) */
+	int	gpio_nce[MAX_NAND_PER_CHIP];	/* NCE */
+	int	gpio_rdy[MAX_NAND_PER_CHIP];	/* RDY (Optional) */
 	void	(*adjust_parts)(struct gpio_nand_platdata *, size_t);
 	struct mtd_partition *parts;
 	unsigned int num_parts;
-- 
1.8.1.5

Re: [PATCH v3 4/4] mtd: nand: gpio: Add support for multichip devices

[Pawel Moll]

On Tue, 2013-08-06 at 09:57 +0100, Alexander Shiyan wrote:
> This patch adds support for multichip NAND devices controlled through GPIOs.
> To implement this, the properties of tree have been renamed. All current
> boards and DTS files converted to use an updated driver. Also driver
> temporarily keep support for DTS files which use the previous names scheme.
> 
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> ---
>  .../devicetree/bindings/mtd/gpio-control-nand.txt  |  16 +--
>  arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts       |  10 +-
>  arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts       |  10 +-

For the bindings part:

Acked-by: Pawel Moll <pawel.moll@arm.com>

Re: [PATCH v3 4/4] mtd: nand: gpio: Add support for multichip devices

[Mark Rutland]

On Tue, Aug 06, 2013 at 09:57:39AM +0100, Alexander Shiyan wrote:
> This patch adds support for multichip NAND devices controlled through GPIOs.
> To implement this, the properties of tree have been renamed. All current
> boards and DTS files converted to use an updated driver. Also driver
> temporarily keep support for DTS files which use the previous names scheme.
> 
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> ---
>  .../devicetree/bindings/mtd/gpio-control-nand.txt  |  16 +--
>  arch/arm/boot/dts/picoxcell-pc7302-pc3x2.dts       |  10 +-
>  arch/arm/boot/dts/picoxcell-pc7302-pc3x3.dts       |  10 +-
>  arch/arm/mach-clps711x/board-autcpu12.c            |   4 +-
>  arch/arm/mach-clps711x/board-p720t.c               |   4 +-
>  arch/arm/mach-pxa/cm-x255.c                        |  10 +-
>  drivers/mtd/nand/gpio.c                            | 108 +++++++++++++++------
>  include/linux/mtd/nand-gpio.h                      |  12 ++-
>  8 files changed, 112 insertions(+), 62 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
> index 91070d0..c58210a 100644
> --- a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
> +++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
> @@ -11,8 +11,11 @@ Required properties:
>    are made in native endianness.

Unrelated, but the above like sounds mighty suspicious and possibly
meaningless...

>  - #address-cells, #size-cells : Must be present if the device has sub-nodes
>    representing partitions.
> -- gpios : specifies the gpio pins to control the NAND device.  nwp is an
> -  optional gpio and may be set to 0 if not present.

I'm not against deprecating this property, as the new mechanism is far
more flexible, and gets rid of the odd nwp case. However I think the
documentation for the old property should be kept (though marked as
deprecated). I'd be happy with a "Deprecated properties" section as with
the regulator bindings.

I'm not sure about changing the dts immediately as this prevents using
them with an old kernel, and creates a lot of churn, given the existing
binding will be supported for the transitionary period...

> +- ale-gpios : specifies the ALE gpio pin.
> +- cle-gpios : specifies the CLE gpio pin.
> +- nwp-gpios : specifies the NWP gpio pin (Optional).
> +- nce-gpios : specifies the NCE gpio pin or several NCE GPIOs for multichip NAND.
> +- rdy-gpios : specifies the RDY gpio pin or several RDY GPIOs for multichip NAND.
> 
>  Optional properties:
>  - bank-width : Width (in bytes) of the device.  If not present, the width
> @@ -37,11 +40,10 @@ gpio-nand@1,0 {
>         reg = <1 0x0000 0x2>;
>         #address-cells = <1>;
>         #size-cells = <1>;
> -       gpios = <&banka 1 0     /* rdy */
> -                &banka 2 0     /* nce */
> -                &banka 3 0     /* ale */
> -                &banka 4 0     /* cle */
> -                0              /* nwp */>;
> +       ale-gpios = <&banka 3 0>;
> +       cle-gpios = <&banka 4 0>;
> +       nce-gpios = <&banka 2 0>;
> +       rdy-gpios = <&banka 1 0>;

It would be nice to have a multichip NAND example, also.

Thanks,
Mark.