[PATCHv3] mtd: gpio-nand: add device tree bindings
Jamie Iles
jamie at jamieiles.com
Mon Aug 1 10:02:54 EDT 2011
Add device tree bindings so that the gpio-nand driver may be
instantiated from the device tree. This also allows the partitions
to be specified in the device tree.
v3:
- remove redundant cast and a couple of whitespace/naming
changes
v2:
- add CONFIG_OF guards for non-dt platforms
- compatible becomes gpio-control-nand
- clarify some binding details
Cc: David Woodhouse <dwmw2 at infradead.org>
Cc: Artem Bityutskiy <dedekind1 at gmail.com>
Acked-by: Grant Likely <grant.likely at secretlab.ca>
Signed-off-by: Jamie Iles <jamie at jamieiles.com>
---
.../devicetree/bindings/mtd/gpio-control-nand.txt | 40 ++++++++
drivers/mtd/nand/gpio.c | 95 ++++++++++++++++++--
2 files changed, 129 insertions(+), 6 deletions(-)
create mode 100644 Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
diff --git a/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
new file mode 100644
index 0000000..2dc52de
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
@@ -0,0 +1,40 @@
+GPIO assisted NAND flash
+
+The GPIO assisted NAND flash uses a memory mapped interface to
+read/write the NAND commands and data and GPIO pins for the control
+signals.
+
+Required properties:
+- compatible : "gpio-control-nand"
+- reg : should specify localbus chip select and size used for the chip. For
+ ARM platforms where a dummy read is needed to provide synchronisation with
+ regards to bus reordering, an optional second resource describes the
+ location to read from.
+- #address-cells, #size-cells : Must be present if the device has sub-nodes
+ representing partitions. In this case, both #address-cells and #size-cells
+ must be equal to 1.
+- gpios : specifies the gpio pins to control the NAND device. nwp is an
+ optional gpio and may be set to 0 if not present.
+
+Optional properties:
+- bank-width : Width (in bytes) of the device.
+- chip-delay : chip dependent delay for transferring data from array to
+ read registers (tR).
+
+Examples:
+
+gpio-nand at 1,0 {
+ compatible = "gpio-control-nand";
+ reg = <1 0x0000 0x1000>;
+ #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 */>;
+
+ partition at 0 {
+ ...
+ };
+};
diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
index 2c2060b..045426b 100644
--- a/drivers/mtd/nand/gpio.c
+++ b/drivers/mtd/nand/gpio.c
@@ -27,6 +27,9 @@
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand-gpio.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_gpio.h>
struct gpiomtd {
void __iomem *io_sync;
@@ -221,14 +224,79 @@ static void __iomem *request_and_remap(struct resource *res, size_t size,
return ptr;
}
+#ifdef CONFIG_OF
+static const struct of_device_id gpio_nand_id_table[] = {
+ { .compatible = "gpio-control-nand" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
+
+static int gpio_nand_of_get_options(struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ u32 width;
+
+ if (!of_property_read_u32(dev->of_node, "bank-width", &width)) {
+ if (width == 2) {
+ plat->options |= NAND_BUSWIDTH_16;
+ } else if (width != 1) {
+ dev_err(dev, "invalid bank-width %u\n", width);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static void gpio_nand_of_get_gpio(struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ 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);
+}
+
+static void gpio_nand_of_get_chip_delay(struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ u32 chip_delay;
+
+ if (!of_property_read_u32(dev->of_node, "chip-delay", &chip_delay))
+ plat->chip_delay = (int)chip_delay;
+}
+
+static int gpio_nand_of_get_config(struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ int ret = gpio_nand_of_get_options(dev, plat);
+
+ if (ret < 0)
+ return ret;
+
+ gpio_nand_of_get_gpio(dev, plat);
+ gpio_nand_of_get_chip_delay(dev, plat);
+
+ return 0;
+}
+#else /* CONFIG_OF */
+#define gpio_nand_id_table NULL
+static inline int gpio_nand_of_get_config(struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ return -ENODEV;
+}
+#endif /* CONFIG_OF */
+
static int __devinit gpio_nand_probe(struct platform_device *dev)
{
struct gpiomtd *gpiomtd;
struct nand_chip *this;
struct resource *res0, *res1;
- int ret;
+ int ret = 0;
- if (!dev->dev.platform_data)
+ if (!dev->dev.of_node && !dev->dev.platform_data)
return -EINVAL;
res0 = platform_get_resource(dev, IORESOURCE_MEM, 0);
@@ -257,7 +325,13 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
}
}
- memcpy(&gpiomtd->plat, dev->dev.platform_data, sizeof(gpiomtd->plat));
+ if (dev->dev.platform_data)
+ memcpy(&gpiomtd->plat, dev->dev.platform_data,
+ sizeof(gpiomtd->plat));
+ else
+ ret = gpio_nand_of_get_config(&dev->dev, &gpiomtd->plat);
+ if (ret)
+ goto err_nce;
ret = gpio_request(gpiomtd->plat.gpio_nce, "NAND NCE");
if (ret)
@@ -312,10 +386,18 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
goto err_wp;
}
- if (gpiomtd->plat.adjust_parts)
- gpiomtd->plat.adjust_parts(&gpiomtd->plat,
- gpiomtd->mtd_info.size);
+ if (dev->dev.platform_data) {
+ if (gpiomtd->plat.adjust_parts)
+ gpiomtd->plat.adjust_parts(&gpiomtd->plat,
+ gpiomtd->mtd_info.size);
+ } else {
+ ret = of_mtd_parse_partitions(&dev->dev, dev->dev.of_node,
+ &gpiomtd->plat.parts);
+ if (ret < 0)
+ goto err_wp;
+ gpiomtd->plat.num_parts = ret;
+ }
mtd_device_register(&gpiomtd->mtd_info, gpiomtd->plat.parts,
gpiomtd->plat.num_parts);
platform_set_drvdata(dev, gpiomtd);
@@ -352,6 +434,7 @@ static struct platform_driver gpio_nand_driver = {
.remove = gpio_nand_remove,
.driver = {
.name = "gpio-nand",
+ .of_match_table = gpio_nand_id_table,
},
};
--
1.7.4.1
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