[PATCH] mtd: gpio-nand: add device tree bindings
Jamie Iles
jamie at jamieiles.com
Sun Dec 18 05:00:49 EST 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.
v7: - restore runtime device tree/non device tree detection
v6: - convert to mtd_device_parse_register()
v5: - fold dt config helpers into a single gpio_nand_of_get_config()
v4: - get io sync address from gpio-control-nand,io-sync-reg
property rather than a resource
- clarified a few details in the binding
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>
Cc: Scott Wood <scottwood at freescale.com>
Cc: Grant Likely <grant.likely at secretlab.ca>
Signed-off-by: Jamie Iles <jamie at jamieiles.com>
---
.../devicetree/bindings/mtd/gpio-control-nand.txt | 44 ++++++++
drivers/mtd/nand/gpio.c | 115 ++++++++++++++++++--
2 files changed, 152 insertions(+), 7 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..719f4dc
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpio-control-nand.txt
@@ -0,0 +1,44 @@
+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. The
+ resource describes the data bus connected to the NAND flash and all accesses
+ 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.
+
+Optional properties:
+- bank-width : Width (in bytes) of the device. If not present, the width
+ 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,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
+ GPIO state and before and after command byte writes, this register will be
+ read to ensure that the GPIO accesses have completed.
+
+Examples:
+
+gpio-nand at 1,0 {
+ compatible = "gpio-control-nand";
+ 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 */>;
+
+ partition at 0 {
+ ...
+ };
+};
diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
index 2c2060b..d4b5609 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;
@@ -171,6 +174,96 @@ static int gpio_nand_devready(struct mtd_info *mtd)
return gpio_get_value(gpiomtd->plat.gpio_rdy);
}
+#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_get_config_of(const struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ u32 val;
+
+ if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
+ if (val == 2) {
+ plat->options |= NAND_BUSWIDTH_16;
+ } else if (val != 1) {
+ dev_err(dev, "invalid bank-width %u\n", val);
+ return -EINVAL;
+ }
+ }
+
+ 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_property_read_u32(dev->of_node, "chip-delay", &val))
+ plat->chip_delay = val;
+
+ return 0;
+}
+
+static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
+{
+ struct resource *r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
+ u64 addr;
+
+ if (!r || of_property_read_u64(pdev->dev.of_node,
+ "gpio-control-nand,io-sync-reg", &addr))
+ return NULL;
+
+ r->start = addr;
+ r->end = r->start + 0x3;
+ r->flags = IORESOURCE_MEM;
+
+ return r;
+}
+#else /* CONFIG_OF */
+#define gpio_nand_id_table NULL
+static inline int gpio_nand_get_config_of(const struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ return -ENOSYS;
+}
+
+static inline struct resource *
+gpio_nand_get_io_sync_of(struct platform_device *pdev)
+{
+ return NULL
+}
+#endif /* CONFIG_OF */
+
+static inline int gpio_nand_get_config(const struct device *dev,
+ struct gpio_nand_platdata *plat)
+{
+ int ret = gpio_nand_get_config_of(dev, plat);
+
+ if (!ret)
+ return ret;
+
+ if (dev->platform_data) {
+ memcpy(plat, dev->platform_data, sizeof(*plat));
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static inline struct resource *
+gpio_nand_get_io_sync(struct platform_device *pdev)
+{
+ struct resource *r = gpio_nand_get_io_sync_of(pdev);
+
+ if (r)
+ return r;
+
+ return platform_get_resource(pdev, IORESOURCE_MEM, 1);
+}
+
static int __devexit gpio_nand_remove(struct platform_device *dev)
{
struct gpiomtd *gpiomtd = platform_get_drvdata(dev);
@@ -178,7 +271,7 @@ static int __devexit gpio_nand_remove(struct platform_device *dev)
nand_release(&gpiomtd->mtd_info);
- res = platform_get_resource(dev, IORESOURCE_MEM, 1);
+ res = gpio_nand_get_io_sync(dev);
iounmap(gpiomtd->io_sync);
if (res)
release_mem_region(res->start, resource_size(res));
@@ -226,9 +319,10 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
struct gpiomtd *gpiomtd;
struct nand_chip *this;
struct resource *res0, *res1;
- int ret;
+ struct mtd_part_parser_data ppdata = {};
+ 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);
@@ -248,7 +342,7 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
goto err_map;
}
- res1 = platform_get_resource(dev, IORESOURCE_MEM, 1);
+ res1 = gpio_nand_get_io_sync(dev);
if (res1) {
gpiomtd->io_sync = request_and_remap(res1, 4, "NAND sync", &ret);
if (!gpiomtd->io_sync) {
@@ -257,7 +351,9 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
}
}
- memcpy(&gpiomtd->plat, dev->dev.platform_data, sizeof(gpiomtd->plat));
+ ret = gpio_nand_get_config(&dev->dev, &gpiomtd->plat);
+ if (ret)
+ goto err_nce;
ret = gpio_request(gpiomtd->plat.gpio_nce, "NAND NCE");
if (ret)
@@ -316,8 +412,12 @@ static int __devinit gpio_nand_probe(struct platform_device *dev)
gpiomtd->plat.adjust_parts(&gpiomtd->plat,
gpiomtd->mtd_info.size);
- mtd_device_register(&gpiomtd->mtd_info, gpiomtd->plat.parts,
- gpiomtd->plat.num_parts);
+ ppdata.of_node = dev->dev.of_node;
+ ret = mtd_device_parse_register(&gpiomtd->mtd_info, NULL, &ppdata,
+ gpiomtd->plat.parts,
+ gpiomtd->plat.num_parts);
+ if (ret)
+ goto err_wp;
platform_set_drvdata(dev, gpiomtd);
return 0;
@@ -352,6 +452,7 @@ static struct platform_driver gpio_nand_driver = {
.remove = gpio_nand_remove,
.driver = {
.name = "gpio-nand",
+ .of_match_table = gpio_nand_id_table,
},
};
--
1.7.5.4
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