LinuxLists.cc - [PATCH v2] mtd: nand: Add OX820 NAND Support

2016-10-20 08:49:13

Subject: [PATCH v2] mtd: nand: Add OX820 NAND Support

Add NAND driver to support the Oxford Semiconductor OX820 NAND Controller.
This is a simple memory mapped NAND controller with single chip select and
software ECC.

Acked-by: Rob Herring <[email protected]>
Signed-off-by: Neil Armstrong <[email protected]>
---
.../devicetree/bindings/mtd/oxnas-nand.txt | 41 +++++
drivers/mtd/nand/Kconfig | 5 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/oxnas_nand.c | 196 +++++++++++++++++++++
4 files changed, 243 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mtd/oxnas-nand.txt
create mode 100644 drivers/mtd/nand/oxnas_nand.c

Changes since v1 http://lkml.kernel.org/r/[email protected] :
- Simplify cmd_ctrl command and drop the ctrl address offset
- Change oxnas_nand struct name to oxnas_nand_ctrl
- Update DT-Bindings example to reflect the ctrl->chip->partitions hierarchy

Changes since RFC http://lkml.kernel.org/r/[email protected] :
- Avoid using chip->IO_ADDR*
- Use new DT structure
- Assign a chip for the subnode
- Use the nand_hw_control structure
- Cleanup probe
- Cleanup cmd_ctrl by using a context ctrl offset used in write_bytes

diff --git a/Documentation/devicetree/bindings/mtd/oxnas-nand.txt b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
new file mode 100644
index 0000000..33a77b8
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
@@ -0,0 +1,41 @@
+* Oxford Semiconductor OXNAS NAND Controller
+
+Please refer to nand.txt for generic information regarding MTD NAND bindings.
+
+Required properties:
+ - compatible: "oxsemi,ox820-nand"
+ - reg: Base address and length for NAND mapped memory.
+
+Optional Properties:
+ - clocks: phandle to the NAND gate clock if needed.
+ - resets: phandle to the NAND reset control if needed.
+
+Example:
+
+nand: nand-controller@41000000 {
+ compatible = "oxsemi,ox820-nand";
+ reg = <0x41000000 0x100000>;
+ clocks = <&stdclk CLK_820_NAND>;
+ resets = <&reset RESET_NAND>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ nand@0 {
+ reg = <0>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ nand-ecc-mode = "soft";
+ nand-ecc-algo = "hamming";
+
+ partition@0 {
+ label = "boot";
+ reg = <0x00000000 0x00e00000>;
+ read-only;
+ };
+
+ partition@e00000 {
+ label = "ubi";
+ reg = <0x00e00000 0x07200000>;
+ };
+ };
+};
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 7b7a887..c023125 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -426,6 +426,11 @@ config MTD_NAND_ORION
No board specific support is done by this driver, each board
must advertise a platform_device for the driver to attach.

+config MTD_NAND_OXNAS
+ tristate "NAND Flash support for Oxford Semiconductor SoC"
+ help
+ This enables the NAND flash controller on Oxford Semiconductor SoCs.
+
config MTD_NAND_FSL_ELBC
tristate "NAND support for Freescale eLBC controllers"
depends on FSL_SOC
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index cafde6f..05fc054 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_MTD_NAND_TMIO) += tmio_nand.o
obj-$(CONFIG_MTD_NAND_PLATFORM) += plat_nand.o
obj-$(CONFIG_MTD_NAND_PASEMI) += pasemi_nand.o
obj-$(CONFIG_MTD_NAND_ORION) += orion_nand.o
+obj-$(CONFIG_MTD_NAND_OXNAS) += oxnas_nand.o
obj-$(CONFIG_MTD_NAND_FSL_ELBC) += fsl_elbc_nand.o
obj-$(CONFIG_MTD_NAND_FSL_IFC) += fsl_ifc_nand.o
obj-$(CONFIG_MTD_NAND_FSL_UPM) += fsl_upm.o
diff --git a/drivers/mtd/nand/oxnas_nand.c b/drivers/mtd/nand/oxnas_nand.c
new file mode 100644
index 0000000..35c94af
--- /dev/null
+++ b/drivers/mtd/nand/oxnas_nand.c
@@ -0,0 +1,196 @@
+/*
+ * Oxford Semiconductor OXNAS NAND driver
+
+ * Copyright (C) 2016 Neil Armstrong <[email protected]>
+ * Heavily based on plat_nand.c :
+ * Author: Vitaly Wool <[email protected]>
+ * Copyright (C) 2013 Ma Haijun <[email protected]>
+ * Copyright (C) 2012 John Crispin <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/reset.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/of.h>
+
+/* Nand commands */
+#define OXNAS_NAND_CMD_ALE BIT(18)
+#define OXNAS_NAND_CMD_CLE BIT(19)
+
+#define OXNAS_NAND_MAX_CHIPS 1
+
+struct oxnas_nand_ctrl {
+ struct nand_hw_control base;
+ void __iomem *io_base;
+ struct clk *clk;
+ struct nand_chip *chips[OXNAS_NAND_MAX_CHIPS];
+};
+
+static uint8_t oxnas_nand_read_byte(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+ struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
+
+ return readb(oxnas->io_base);
+}
+
+static void oxnas_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+ struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
+
+ ioread8_rep(oxnas->io_base, buf, len);
+}
+
+static void oxnas_nand_write_buf(struct mtd_info *mtd,
+ const uint8_t *buf, int len)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+ struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
+
+ iowrite8_rep(oxnas->io_base, buf, len);
+}
+
+/* Single CS command control */
+static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
+ unsigned int ctrl)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+ struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
+
+ if (ctrl & NAND_CLE)
+ writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_CLE);
+ else if (ctrl & NAND_ALE)
+ writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_ALE);
+}
+
+/*
+ * Probe for the NAND device.
+ */
+static int oxnas_nand_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device_node *nand_np;
+ struct oxnas_nand_ctrl *oxnas;
+ struct nand_chip *chip;
+ struct mtd_info *mtd;
+ struct resource *res;
+ int nchips = 0;
+ int count = 0;
+ int err = 0;
+
+ /* Allocate memory for the device structure (and zero it) */
+ oxnas = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
+ GFP_KERNEL);
+ if (!oxnas)
+ return -ENOMEM;
+
+ nand_hw_control_init(&oxnas->base);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ oxnas->io_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(oxnas->io_base))
+ return PTR_ERR(oxnas->io_base);
+
+ oxnas->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(oxnas->clk))
+ oxnas->clk = NULL;
+
+ /* Only a single chip node is supported */
+ count = of_get_child_count(np);
+ if (count > 1)
+ return -EINVAL;
+
+ clk_prepare_enable(oxnas->clk);
+ device_reset_optional(&pdev->dev);
+
+ for_each_child_of_node(np, nand_np) {
+ chip = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
+ GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->controller = &oxnas->base;
+
+ nand_set_flash_node(chip, nand_np);
+ nand_set_controller_data(chip, oxnas);
+
+ mtd = nand_to_mtd(chip);
+ mtd->dev.parent = &pdev->dev;
+ mtd->priv = chip;
+
+ chip->cmd_ctrl = oxnas_nand_cmd_ctrl;
+ chip->read_buf = oxnas_nand_read_buf;
+ chip->read_byte = oxnas_nand_read_byte;
+ chip->write_buf = oxnas_nand_write_buf;
+ chip->chip_delay = 30;
+
+ /* Scan to find existence of the device */
+ err = nand_scan(mtd, 1);
+ if (err)
+ return err;
+
+ err = mtd_device_register(mtd, NULL, 0);
+ if (err) {
+ nand_release(mtd);
+ return err;
+ }
+
+ oxnas->chips[nchips] = chip;
+ ++nchips;
+ }
+
+ /* Exit if no chips found */
+ if (!nchips)
+ return -ENODEV;
+
+ platform_set_drvdata(pdev, oxnas);
+
+ return 0;
+}
+
+static int oxnas_nand_remove(struct platform_device *pdev)
+{
+ struct oxnas_nand_ctrl *oxnas = platform_get_drvdata(pdev);
+
+ if (oxnas->chips[0])
+ nand_release(nand_to_mtd(oxnas->chips[0]));
+
+ clk_disable_unprepare(oxnas->clk);
+
+ return 0;
+}
+
+static const struct of_device_id oxnas_nand_match[] = {
+ { .compatible = "oxsemi,ox820-nand" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, oxnas_nand_match);
+
+static struct platform_driver oxnas_nand_driver = {
+ .probe = oxnas_nand_probe,
+ .remove = oxnas_nand_remove,
+ .driver = {
+ .name = "oxnas_nand",
+ .of_match_table = oxnas_nand_match,
+ },
+};
+
+module_platform_driver(oxnas_nand_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Neil Armstrong <[email protected]>");
+MODULE_DESCRIPTION("Oxnas NAND driver");
+MODULE_ALIAS("platform:oxnas_nand");
--
2.7.0

2016-10-20 09:00:33

by Boris Brezillon

[permalink] [raw]

Subject: Re: [PATCH v2] mtd: nand: Add OX820 NAND Support

2016-10-20 09:04:45

by Neil Armstrong

[permalink] [raw]

Subject: Re: [PATCH v2] mtd: nand: Add OX820 NAND Support

On 10/20/2016 11:00 AM, Boris Brezillon wrote:
> On Thu, 20 Oct 2016 10:49:01 +0200
> Neil Armstrong <[email protected]> wrote:
>
>> Add NAND driver to support the Oxford Semiconductor OX820 NAND Controller.
>> This is a simple memory mapped NAND controller with single chip select and
>> software ECC.
>>
>> Acked-by: Rob Herring <[email protected]>
>> Signed-off-by: Neil Armstrong <[email protected]>
>> ---
>> .../devicetree/bindings/mtd/oxnas-nand.txt | 41 +++++
>> drivers/mtd/nand/Kconfig | 5 +
>> drivers/mtd/nand/Makefile | 1 +
>> drivers/mtd/nand/oxnas_nand.c | 196 +++++++++++++++++++++
>> 4 files changed, 243 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/mtd/oxnas-nand.txt
>> create mode 100644 drivers/mtd/nand/oxnas_nand.c
>>
>> Changes since v1 http://lkml.kernel.org/r/[email protected] :
>> - Simplify cmd_ctrl command and drop the ctrl address offset
>> - Change oxnas_nand struct name to oxnas_nand_ctrl
>> - Update DT-Bindings example to reflect the ctrl->chip->partitions hierarchy
>>
>> Changes since RFC http://lkml.kernel.org/r/[email protected] :
>> - Avoid using chip->IO_ADDR*
>> - Use new DT structure
>> - Assign a chip for the subnode
>> - Use the nand_hw_control structure
>> - Cleanup probe
>> - Cleanup cmd_ctrl by using a context ctrl offset used in write_bytes
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/oxnas-nand.txt b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
>> new file mode 100644
>> index 0000000..33a77b8
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
>> @@ -0,0 +1,41 @@
>> +* Oxford Semiconductor OXNAS NAND Controller
>> +
>> +Please refer to nand.txt for generic information regarding MTD NAND bindings.
>> +
>> +Required properties:
>> + - compatible: "oxsemi,ox820-nand"
>> + - reg: Base address and length for NAND mapped memory.
>> +
>> +Optional Properties:
>> + - clocks: phandle to the NAND gate clock if needed.
>> + - resets: phandle to the NAND reset control if needed.
>> +
>> +Example:
>> +
>> +nand: nand-controller@41000000 {
>
> 'nandc:' or 'nand_ctrl:'
>
> Otherwise it may conflict with a NAND chip alias.
> The rest looks good, so no need to send a new version (I can fix it when
> applying the patch).

OK, thanks, I will fix in the dtsi accordingly.

>
> One last thing, I saw there was other people owning boards with this
> controller. Can I get one or two Tested-by?

I would like too, but it seems I'm the only one working upstream for now....
I hope it will change in near future once there is enough upstream for booting the platform.

>
> Thanks taking my reviews into account.

Thanks for reviewing !

Neil
>
> Regards,
>
> Boris
>

2016-10-22 12:36:44

by Boris Brezillon

[permalink] [raw]

Subject: Re: [PATCH v2] mtd: nand: Add OX820 NAND Support

On Thu, 20 Oct 2016 10:49:01 +0200
Neil Armstrong <[email protected]> wrote:

> Add NAND driver to support the Oxford Semiconductor OX820 NAND Controller.
> This is a simple memory mapped NAND controller with single chip select and
> software ECC.
>
> Acked-by: Rob Herring <[email protected]>
> Signed-off-by: Neil Armstrong <[email protected]>

Applied.

Thanks,

Boris

> ---
> .../devicetree/bindings/mtd/oxnas-nand.txt | 41 +++++
> drivers/mtd/nand/Kconfig | 5 +
> drivers/mtd/nand/Makefile | 1 +
> drivers/mtd/nand/oxnas_nand.c | 196 +++++++++++++++++++++
> 4 files changed, 243 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mtd/oxnas-nand.txt
> create mode 100644 drivers/mtd/nand/oxnas_nand.c
>
> Changes since v1 http://lkml.kernel.org/r/[email protected] :
> - Simplify cmd_ctrl command and drop the ctrl address offset
> - Change oxnas_nand struct name to oxnas_nand_ctrl
> - Update DT-Bindings example to reflect the ctrl->chip->partitions hierarchy
>
> Changes since RFC http://lkml.kernel.org/r/[email protected] :
> - Avoid using chip->IO_ADDR*
> - Use new DT structure
> - Assign a chip for the subnode
> - Use the nand_hw_control structure
> - Cleanup probe
> - Cleanup cmd_ctrl by using a context ctrl offset used in write_bytes
>
> diff --git a/Documentation/devicetree/bindings/mtd/oxnas-nand.txt b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
> new file mode 100644
> index 0000000..33a77b8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
> @@ -0,0 +1,41 @@
> +* Oxford Semiconductor OXNAS NAND Controller
> +
> +Please refer to nand.txt for generic information regarding MTD NAND bindings.
> +
> +Required properties:
> + - compatible: "oxsemi,ox820-nand"
> + - reg: Base address and length for NAND mapped memory.
> +
> +Optional Properties:
> + - clocks: phandle to the NAND gate clock if needed.
> + - resets: phandle to the NAND reset control if needed.
> +
> +Example:
> +
> +nand: nand-controller@41000000 {
> + compatible = "oxsemi,ox820-nand";
> + reg = <0x41000000 0x100000>;
> + clocks = <&stdclk CLK_820_NAND>;
> + resets = <&reset RESET_NAND>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + nand@0 {
> + reg = <0>;
> + #address-cells = <1>;
> + #size-cells = <1>;
> + nand-ecc-mode = "soft";
> + nand-ecc-algo = "hamming";
> +
> + partition@0 {
> + label = "boot";
> + reg = <0x00000000 0x00e00000>;
> + read-only;
> + };
> +
> + partition@e00000 {
> + label = "ubi";
> + reg = <0x00e00000 0x07200000>;
> + };
> + };
> +};
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 7b7a887..c023125 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -426,6 +426,11 @@ config MTD_NAND_ORION
> No board specific support is done by this driver, each board
> must advertise a platform_device for the driver to attach.
>
> +config MTD_NAND_OXNAS
> + tristate "NAND Flash support for Oxford Semiconductor SoC"
> + help
> + This enables the NAND flash controller on Oxford Semiconductor SoCs.
> +
> config MTD_NAND_FSL_ELBC
> tristate "NAND support for Freescale eLBC controllers"
> depends on FSL_SOC
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index cafde6f..05fc054 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_MTD_NAND_TMIO) += tmio_nand.o
> obj-$(CONFIG_MTD_NAND_PLATFORM) += plat_nand.o
> obj-$(CONFIG_MTD_NAND_PASEMI) += pasemi_nand.o
> obj-$(CONFIG_MTD_NAND_ORION) += orion_nand.o
> +obj-$(CONFIG_MTD_NAND_OXNAS) += oxnas_nand.o
> obj-$(CONFIG_MTD_NAND_FSL_ELBC) += fsl_elbc_nand.o
> obj-$(CONFIG_MTD_NAND_FSL_IFC) += fsl_ifc_nand.o
> obj-$(CONFIG_MTD_NAND_FSL_UPM) += fsl_upm.o
> diff --git a/drivers/mtd/nand/oxnas_nand.c b/drivers/mtd/nand/oxnas_nand.c
> new file mode 100644
> index 0000000..35c94af
> --- /dev/null
> +++ b/drivers/mtd/nand/oxnas_nand.c
> @@ -0,0 +1,196 @@
> +/*
> + * Oxford Semiconductor OXNAS NAND driver
> +
> + * Copyright (C) 2016 Neil Armstrong <[email protected]>
> + * Heavily based on plat_nand.c :
> + * Author: Vitaly Wool <[email protected]>
> + * Copyright (C) 2013 Ma Haijun <[email protected]>
> + * Copyright (C) 2012 John Crispin <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/of.h>
> +
> +/* Nand commands */
> +#define OXNAS_NAND_CMD_ALE BIT(18)
> +#define OXNAS_NAND_CMD_CLE BIT(19)
> +
> +#define OXNAS_NAND_MAX_CHIPS 1
> +
> +struct oxnas_nand_ctrl {
> + struct nand_hw_control base;
> + void __iomem *io_base;
> + struct clk *clk;
> + struct nand_chip *chips[OXNAS_NAND_MAX_CHIPS];
> +};
> +
> +static uint8_t oxnas_nand_read_byte(struct mtd_info *mtd)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
> +
> + return readb(oxnas->io_base);
> +}
> +
> +static void oxnas_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
> +
> + ioread8_rep(oxnas->io_base, buf, len);
> +}
> +
> +static void oxnas_nand_write_buf(struct mtd_info *mtd,
> + const uint8_t *buf, int len)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
> +
> + iowrite8_rep(oxnas->io_base, buf, len);
> +}
> +
> +/* Single CS command control */
> +static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
> + unsigned int ctrl)
> +{
> + struct nand_chip *chip = mtd_to_nand(mtd);
> + struct oxnas_nand_ctrl *oxnas = nand_get_controller_data(chip);
> +
> + if (ctrl & NAND_CLE)
> + writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_CLE);
> + else if (ctrl & NAND_ALE)
> + writeb(cmd, oxnas->io_base + OXNAS_NAND_CMD_ALE);
> +}
> +
> +/*
> + * Probe for the NAND device.
> + */
> +static int oxnas_nand_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct device_node *nand_np;
> + struct oxnas_nand_ctrl *oxnas;
> + struct nand_chip *chip;
> + struct mtd_info *mtd;
> + struct resource *res;
> + int nchips = 0;
> + int count = 0;
> + int err = 0;
> +
> + /* Allocate memory for the device structure (and zero it) */
> + oxnas = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
> + GFP_KERNEL);
> + if (!oxnas)
> + return -ENOMEM;
> +
> + nand_hw_control_init(&oxnas->base);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + oxnas->io_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(oxnas->io_base))
> + return PTR_ERR(oxnas->io_base);
> +
> + oxnas->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(oxnas->clk))
> + oxnas->clk = NULL;
> +
> + /* Only a single chip node is supported */
> + count = of_get_child_count(np);
> + if (count > 1)
> + return -EINVAL;
> +
> + clk_prepare_enable(oxnas->clk);
> + device_reset_optional(&pdev->dev);
> +
> + for_each_child_of_node(np, nand_np) {
> + chip = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
> + GFP_KERNEL);
> + if (!chip)
> + return -ENOMEM;
> +
> + chip->controller = &oxnas->base;
> +
> + nand_set_flash_node(chip, nand_np);
> + nand_set_controller_data(chip, oxnas);
> +
> + mtd = nand_to_mtd(chip);
> + mtd->dev.parent = &pdev->dev;
> + mtd->priv = chip;
> +
> + chip->cmd_ctrl = oxnas_nand_cmd_ctrl;
> + chip->read_buf = oxnas_nand_read_buf;
> + chip->read_byte = oxnas_nand_read_byte;
> + chip->write_buf = oxnas_nand_write_buf;
> + chip->chip_delay = 30;
> +
> + /* Scan to find existence of the device */
> + err = nand_scan(mtd, 1);
> + if (err)
> + return err;
> +
> + err = mtd_device_register(mtd, NULL, 0);
> + if (err) {
> + nand_release(mtd);
> + return err;
> + }
> +
> + oxnas->chips[nchips] = chip;
> + ++nchips;
> + }
> +
> + /* Exit if no chips found */
> + if (!nchips)
> + return -ENODEV;
> +
> + platform_set_drvdata(pdev, oxnas);
> +
> + return 0;
> +}
> +
> +static int oxnas_nand_remove(struct platform_device *pdev)
> +{
> + struct oxnas_nand_ctrl *oxnas = platform_get_drvdata(pdev);
> +
> + if (oxnas->chips[0])
> + nand_release(nand_to_mtd(oxnas->chips[0]));
> +
> + clk_disable_unprepare(oxnas->clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id oxnas_nand_match[] = {
> + { .compatible = "oxsemi,ox820-nand" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, oxnas_nand_match);
> +
> +static struct platform_driver oxnas_nand_driver = {
> + .probe = oxnas_nand_probe,
> + .remove = oxnas_nand_remove,
> + .driver = {
> + .name = "oxnas_nand",
> + .of_match_table = oxnas_nand_match,
> + },
> +};
> +
> +module_platform_driver(oxnas_nand_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Neil Armstrong <[email protected]>");
> +MODULE_DESCRIPTION("Oxnas NAND driver");
> +MODULE_ALIAS("platform:oxnas_nand");