diff mbox

[v5,5/6] nand: spi: Add generic SPI controller support

Message ID 1491810713-27795-6-git-send-email-peterpandong@micron.com
State Superseded
Delegated to: Boris Brezillon
Headers show

Commit Message

Peter Pan 潘栋 (peterpandong) April 10, 2017, 7:51 a.m. UTC 
This commit supports to use generic spi controller
as spi nand controller.

Signed-off-by: Peter Pan <peterpandong@micron.com>
---
 drivers/mtd/nand/spi/Kconfig                   |   2 +
 drivers/mtd/nand/spi/Makefile                  |   1 +
 drivers/mtd/nand/spi/controllers/Kconfig       |   5 +
 drivers/mtd/nand/spi/controllers/Makefile      |   1 +
 drivers/mtd/nand/spi/controllers/generic-spi.c | 159 +++++++++++++++++++++++++
 5 files changed, 168 insertions(+)
 create mode 100644 drivers/mtd/nand/spi/controllers/Kconfig
 create mode 100644 drivers/mtd/nand/spi/controllers/Makefile
 create mode 100644 drivers/mtd/nand/spi/controllers/generic-spi.c

Comments

Marek Vasut April 14, 2017, 1:26 p.m. UTC | #1 
On 04/10/2017 09:51 AM, Peter Pan wrote:
> This commit supports to use generic spi controller
> as spi nand controller.
> 
> Signed-off-by: Peter Pan <peterpandong@micron.com>
> ---
>  drivers/mtd/nand/spi/Kconfig                   |   2 +
>  drivers/mtd/nand/spi/Makefile                  |   1 +
>  drivers/mtd/nand/spi/controllers/Kconfig       |   5 +
>  drivers/mtd/nand/spi/controllers/Makefile      |   1 +
>  drivers/mtd/nand/spi/controllers/generic-spi.c | 159 +++++++++++++++++++++++++
>  5 files changed, 168 insertions(+)
>  create mode 100644 drivers/mtd/nand/spi/controllers/Kconfig
>  create mode 100644 drivers/mtd/nand/spi/controllers/Makefile
>  create mode 100644 drivers/mtd/nand/spi/controllers/generic-spi.c

[...]

> +static int gen_spi_spinand_probe(struct spi_device *spi)
> +{
> +	struct spinand_device *chip;
> +	struct gen_spi_spinand_controller *controller;
> +	struct spinand_controller *spinand_controller;
> +	struct device *dev = &spi->dev;
> +	u16 mode = spi->mode;
> +	int ret;
> +
> +	chip = spinand_alloc(dev);
> +	if (IS_ERR(chip)) {
> +		ret = PTR_ERR(chip);
> +		goto err1;
> +	}

Would it make sense to embed the struct spinand_device into struct
gen_spi_nand_controller , so you'd get rid of one allocation ?

> +	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
> +	if (!controller) {
> +		ret = -ENOMEM;
> +		goto err2;
> +	}
> +	controller->spi = spi;
> +	spinand_controller = &controller->ctrl;
> +	spinand_controller->ops = &gen_spi_spinand_ops;
> +	spinand_controller->caps = SPINAND_CAP_RD_X1 | SPINAND_CAP_WR_X1;
> +
> +	if ((mode & SPI_RX_QUAD) && (mode & SPI_TX_QUAD))
> +		spinand_controller->caps |= SPINAND_CAP_RD_QUAD;
> +	if ((mode & SPI_RX_DUAL) && (mode & SPI_TX_DUAL))
> +		spinand_controller->caps |= SPINAND_CAP_RD_DUAL;
> +	if (mode & SPI_RX_QUAD)
> +		spinand_controller->caps |= SPINAND_CAP_RD_X4;
> +	if (mode & SPI_RX_DUAL)
> +		spinand_controller->caps |= SPINAND_CAP_RD_X2;
> +	if (mode & SPI_TX_QUAD)
> +		spinand_controller->caps |= SPINAND_CAP_WR_QUAD |
> +					    SPINAND_CAP_WR_X4;
> +	if (mode & SPI_TX_DUAL)
> +		spinand_controller->caps |= SPINAND_CAP_WR_DUAL |
> +					    SPINAND_CAP_WR_X2;
> +	chip->controller.controller = spinand_controller;
> +	/*
> +	 * generic spi controller doesn't have ecc capability,
> +	 * so use on-die ecc.
> +	 */
> +	chip->ecc.type = SPINAND_ECC_ONDIE;
> +	spi_set_drvdata(spi, chip);
> +
> +	ret = spinand_register(chip);
> +	if (ret)
> +		goto err3;
> +
> +	return 0;
> +
> +err3:
> +	devm_kfree(dev, controller);
> +err2:
> +	spinand_free(chip);
> +err1:
> +	return ret;
> +}
> +
> +static int gen_spi_spinand_remove(struct spi_device *spi)
> +{
> +	struct spinand_device *chip = spi_get_drvdata(spi);
> +	struct spinand_controller *scontroller = chip->controller.controller;
> +	struct gen_spi_spinand_controller *controller;
> +
> +	spinand_unregister(chip);
> +	controller = to_gen_spi_spinand_controller(scontroller);
> +	devm_kfree(&spi->dev, controller);
> +	spinand_free(chip);
> +
> +	return 0;
> +}
> +
> +static struct spi_driver gen_spi_spinand_driver = {
> +	.driver = {
> +		.name	= "generic_spinand",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= gen_spi_spinand_probe,
> +	.remove	= gen_spi_spinand_remove,
> +};
> +module_spi_driver(gen_spi_spinand_driver);
> +
> +MODULE_DESCRIPTION("Generic SPI controller to support SPI NAND");
> +MODULE_AUTHOR("Peter Pan<peterpandong@micron.com>");
> +MODULE_LICENSE("GPL v2");
>
Boris Brezillon April 18, 2017, 7:26 a.m. UTC | #2 
On Mon, 10 Apr 2017 15:51:52 +0800
Peter Pan <peterpandong@micron.com> wrote:

> This commit supports to use generic spi controller
> as spi nand controller.
> 
> Signed-off-by: Peter Pan <peterpandong@micron.com>
> ---
>  drivers/mtd/nand/spi/Kconfig                   |   2 +
>  drivers/mtd/nand/spi/Makefile                  |   1 +
>  drivers/mtd/nand/spi/controllers/Kconfig       |   5 +
>  drivers/mtd/nand/spi/controllers/Makefile      |   1 +
>  drivers/mtd/nand/spi/controllers/generic-spi.c | 159 +++++++++++++++++++++++++
>  5 files changed, 168 insertions(+)
>  create mode 100644 drivers/mtd/nand/spi/controllers/Kconfig
>  create mode 100644 drivers/mtd/nand/spi/controllers/Makefile
>  create mode 100644 drivers/mtd/nand/spi/controllers/generic-spi.c
> 
> diff --git a/drivers/mtd/nand/spi/Kconfig b/drivers/mtd/nand/spi/Kconfig
> index d77c46e..6bd1c65 100644
> --- a/drivers/mtd/nand/spi/Kconfig
> +++ b/drivers/mtd/nand/spi/Kconfig
> @@ -3,3 +3,5 @@ menuconfig MTD_SPI_NAND
>  	depends on MTD_NAND
>  	help
>  	  This is the framework for the SPI NAND device drivers.
> +
> +source "drivers/mtd/nand/spi/controllers/Kconfig"
> diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
> index df6c2ea..822e48d 100644
> --- a/drivers/mtd/nand/spi/Makefile
> +++ b/drivers/mtd/nand/spi/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_MTD_SPI_NAND) += core.o
>  obj-$(CONFIG_MTD_SPI_NAND) += micron.o
> +obj-$(CONFIG_MTD_SPI_NAND) += controllers/
> diff --git a/drivers/mtd/nand/spi/controllers/Kconfig b/drivers/mtd/nand/spi/controllers/Kconfig
> new file mode 100644
> index 0000000..8ab7023
> --- /dev/null
> +++ b/drivers/mtd/nand/spi/controllers/Kconfig
> @@ -0,0 +1,5 @@
> +config GENERIC_SPI_NAND
> +	tristate "SPI NAND with generic SPI bus Support"
> +	depends on MTD_SPI_NAND && SPI
> +	help
> +	  This is to support SPI NAND device with generic SPI bus.
> diff --git a/drivers/mtd/nand/spi/controllers/Makefile b/drivers/mtd/nand/spi/controllers/Makefile
> new file mode 100644
> index 0000000..46cbf29
> --- /dev/null
> +++ b/drivers/mtd/nand/spi/controllers/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_GENERIC_SPI_NAND) += generic-spi.o
> diff --git a/drivers/mtd/nand/spi/controllers/generic-spi.c b/drivers/mtd/nand/spi/controllers/generic-spi.c
> new file mode 100644
> index 0000000..d354874
> --- /dev/null
> +++ b/drivers/mtd/nand/spi/controllers/generic-spi.c
> @@ -0,0 +1,159 @@
> +/*
> + * Copyright (c) 2009-2017 Micron Technology, Inc.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/mtd/spinand.h>
> +
> +struct gen_spi_spinand_controller {
> +	struct spinand_controller ctrl;
> +	struct spi_device *spi;
> +};
> +
> +#define to_gen_spi_spinand_controller(c) \
> +	container_of(c, struct gen_spi_spinand_controller, ctrl)
> +
> +/*
> + * gen_spi_spinand_exec_op - to process a command to send to the
> + * SPI NAND by generic SPI bus
> + * @chip: SPI NAND device structure
> + * @op: SPI NAND operation descriptor
> + */
> +static int gen_spi_spinand_exec_op(struct spinand_device *chip,
> +				   struct spinand_op *op)
> +{
> +	struct spi_message message;
> +	struct spi_transfer x[3];
> +	struct spinand_controller *scontroller = chip->controller.controller;
> +	struct gen_spi_spinand_controller *controller;
> +
> +	controller = to_gen_spi_spinand_controller(scontroller);
> +	spi_message_init(&message);
> +	memset(x, 0, sizeof(x));
> +	x[0].len = 1;
> +	x[0].tx_nbits = 1;
> +	x[0].tx_buf = &op->cmd;
> +	spi_message_add_tail(&x[0], &message);
> +
> +	if (op->n_addr + op->dummy_bytes) {
> +		x[1].len = op->n_addr + op->dummy_bytes;
> +		x[1].tx_nbits = op->addr_nbits;
> +		x[1].tx_buf = op->addr;
> +		spi_message_add_tail(&x[1], &message);
> +	}

Can you add empty lines to separate each block of code (this comment
applies to the whole contribution).

> +	if (op->n_tx) {
> +		x[2].len = op->n_tx;
> +		x[2].tx_nbits = op->data_nbits;
> +		x[2].tx_buf = op->tx_buf;
> +		spi_message_add_tail(&x[2], &message);
> +	} else if (op->n_rx) {
> +		x[2].len = op->n_rx;
> +		x[2].rx_nbits = op->data_nbits;
> +		x[2].rx_buf = op->rx_buf;
> +		spi_message_add_tail(&x[2], &message);
> +	}

Empty line here too.

> +	return spi_sync(controller->spi, &message);
> +}
> +
> +static struct spinand_controller_ops gen_spi_spinand_ops = {
> +	.exec_op = gen_spi_spinand_exec_op,
> +};
> +
> +static int gen_spi_spinand_probe(struct spi_device *spi)
> +{
> +	struct spinand_device *chip;
> +	struct gen_spi_spinand_controller *controller;
> +	struct spinand_controller *spinand_controller;
> +	struct device *dev = &spi->dev;
> +	u16 mode = spi->mode;
> +	int ret;
> +
> +	chip = spinand_alloc(dev);
> +	if (IS_ERR(chip)) {
> +		ret = PTR_ERR(chip);
> +		goto err1;
> +	}

Ditto.

> +	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
> +	if (!controller) {
> +		ret = -ENOMEM;
> +		goto err2;
> +	}

Ditto (I think you got it now, so I'll stop here ;)).

> +	controller->spi = spi;
> +	spinand_controller = &controller->ctrl;
> +	spinand_controller->ops = &gen_spi_spinand_ops;
> +	spinand_controller->caps = SPINAND_CAP_RD_X1 | SPINAND_CAP_WR_X1;
> +
> +	if ((mode & SPI_RX_QUAD) && (mode & SPI_TX_QUAD))
> +		spinand_controller->caps |= SPINAND_CAP_RD_QUAD;
> +	if ((mode & SPI_RX_DUAL) && (mode & SPI_TX_DUAL))
> +		spinand_controller->caps |= SPINAND_CAP_RD_DUAL;
> +	if (mode & SPI_RX_QUAD)
> +		spinand_controller->caps |= SPINAND_CAP_RD_X4;
> +	if (mode & SPI_RX_DUAL)
> +		spinand_controller->caps |= SPINAND_CAP_RD_X2;
> +	if (mode & SPI_TX_QUAD)
> +		spinand_controller->caps |= SPINAND_CAP_WR_QUAD |
> +					    SPINAND_CAP_WR_X4;
> +	if (mode & SPI_TX_DUAL)
> +		spinand_controller->caps |= SPINAND_CAP_WR_DUAL |
> +					    SPINAND_CAP_WR_X2;
> +	chip->controller.controller = spinand_controller;
> +	/*
> +	 * generic spi controller doesn't have ecc capability,
> +	 * so use on-die ecc.
> +	 */
> +	chip->ecc.type = SPINAND_ECC_ONDIE;

Hm, can't we use the DT property to select that? It seems a bit weird
to have on-die ECC enabled by default.

> +	spi_set_drvdata(spi, chip);
> +
> +	ret = spinand_register(chip);
> +	if (ret)
> +		goto err3;
> +
> +	return 0;
> +
> +err3:
> +	devm_kfree(dev, controller);
> +err2:

Already said that earlier, try to find better names for your labels.
Here, err_free_spinand. But anyway, since everything is allocated with
devm_, I think you can just skip these steps.

> +	spinand_free(chip);
> +err1:
> +	return ret;
> +}
> +
> +static int gen_spi_spinand_remove(struct spi_device *spi)
> +{
> +	struct spinand_device *chip = spi_get_drvdata(spi);
> +	struct spinand_controller *scontroller = chip->controller.controller;
> +	struct gen_spi_spinand_controller *controller;
> +
> +	spinand_unregister(chip);
> +	controller = to_gen_spi_spinand_controller(scontroller);
> +	devm_kfree(&spi->dev, controller);
> +	spinand_free(chip);
> +
> +	return 0;
> +}
> +
> +static struct spi_driver gen_spi_spinand_driver = {
> +	.driver = {
> +		.name	= "generic_spinand",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= gen_spi_spinand_probe,
> +	.remove	= gen_spi_spinand_remove,
> +};
> +module_spi_driver(gen_spi_spinand_driver);
> +
> +MODULE_DESCRIPTION("Generic SPI controller to support SPI NAND");
> +MODULE_AUTHOR("Peter Pan<peterpandong@micron.com>");
> +MODULE_LICENSE("GPL v2");
Boris Brezillon April 18, 2017, 7:41 a.m. UTC | #3 
On Fri, 14 Apr 2017 15:26:24 +0200
Marek Vasut <marex@denx.de> wrote:

> On 04/10/2017 09:51 AM, Peter Pan wrote:
> > This commit supports to use generic spi controller
> > as spi nand controller.
> > 
> > Signed-off-by: Peter Pan <peterpandong@micron.com>
> > ---
> >  drivers/mtd/nand/spi/Kconfig                   |   2 +
> >  drivers/mtd/nand/spi/Makefile                  |   1 +
> >  drivers/mtd/nand/spi/controllers/Kconfig       |   5 +
> >  drivers/mtd/nand/spi/controllers/Makefile      |   1 +
> >  drivers/mtd/nand/spi/controllers/generic-spi.c | 159 +++++++++++++++++++++++++
> >  5 files changed, 168 insertions(+)
> >  create mode 100644 drivers/mtd/nand/spi/controllers/Kconfig
> >  create mode 100644 drivers/mtd/nand/spi/controllers/Makefile
> >  create mode 100644 drivers/mtd/nand/spi/controllers/generic-spi.c  
> 
> [...]
> 
> > +static int gen_spi_spinand_probe(struct spi_device *spi)
> > +{
> > +	struct spinand_device *chip;
> > +	struct gen_spi_spinand_controller *controller;
> > +	struct spinand_controller *spinand_controller;
> > +	struct device *dev = &spi->dev;
> > +	u16 mode = spi->mode;
> > +	int ret;
> > +
> > +	chip = spinand_alloc(dev);
> > +	if (IS_ERR(chip)) {
> > +		ret = PTR_ERR(chip);
> > +		goto err1;
> > +	}  
> 
> Would it make sense to embed the struct spinand_device into struct
> gen_spi_nand_controller , so you'd get rid of one allocation ?

I have other plans. I'd like drivers to only register their
SPI NAND controller, and let the core parse the DT (or board info) to
create the spinand devices and inform the controller that a new device
is being added (using a ->add() hook).

With this model, the core does not know anything about driver-specific
private data, and thus has to allocate a spinand device no matter what.

Even if we're not here yet, I'd like to keep that in mind, and already
force SPI NAND controller drivers to use spinand_alloc instead of
embedding the struct.

> 
> > +	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
> > +	if (!controller) {
> > +		ret = -ENOMEM;
> > +		goto err2;
> > +	}
> > +	controller->spi = spi;
> > +	spinand_controller = &controller->ctrl;
> > +	spinand_controller->ops = &gen_spi_spinand_ops;
> > +	spinand_controller->caps = SPINAND_CAP_RD_X1 | SPINAND_CAP_WR_X1;
> > +
> > +	if ((mode & SPI_RX_QUAD) && (mode & SPI_TX_QUAD))
> > +		spinand_controller->caps |= SPINAND_CAP_RD_QUAD;
> > +	if ((mode & SPI_RX_DUAL) && (mode & SPI_TX_DUAL))
> > +		spinand_controller->caps |= SPINAND_CAP_RD_DUAL;
> > +	if (mode & SPI_RX_QUAD)
> > +		spinand_controller->caps |= SPINAND_CAP_RD_X4;
> > +	if (mode & SPI_RX_DUAL)
> > +		spinand_controller->caps |= SPINAND_CAP_RD_X2;
> > +	if (mode & SPI_TX_QUAD)
> > +		spinand_controller->caps |= SPINAND_CAP_WR_QUAD |
> > +					    SPINAND_CAP_WR_X4;
> > +	if (mode & SPI_TX_DUAL)
> > +		spinand_controller->caps |= SPINAND_CAP_WR_DUAL |
> > +					    SPINAND_CAP_WR_X2;
> > +	chip->controller.controller = spinand_controller;
> > +	/*
> > +	 * generic spi controller doesn't have ecc capability,
> > +	 * so use on-die ecc.
> > +	 */
> > +	chip->ecc.type = SPINAND_ECC_ONDIE;
> > +	spi_set_drvdata(spi, chip);
> > +
> > +	ret = spinand_register(chip);
> > +	if (ret)
> > +		goto err3;
> > +
> > +	return 0;
> > +
> > +err3:
> > +	devm_kfree(dev, controller);
> > +err2:
> > +	spinand_free(chip);
> > +err1:
> > +	return ret;
> > +}
> > +
> > +static int gen_spi_spinand_remove(struct spi_device *spi)
> > +{
> > +	struct spinand_device *chip = spi_get_drvdata(spi);
> > +	struct spinand_controller *scontroller = chip->controller.controller;
> > +	struct gen_spi_spinand_controller *controller;
> > +
> > +	spinand_unregister(chip);
> > +	controller = to_gen_spi_spinand_controller(scontroller);
> > +	devm_kfree(&spi->dev, controller);
> > +	spinand_free(chip);
> > +
> > +	return 0;
> > +}
> > +
> > +static struct spi_driver gen_spi_spinand_driver = {
> > +	.driver = {
> > +		.name	= "generic_spinand",
> > +		.owner	= THIS_MODULE,
> > +	},
> > +	.probe	= gen_spi_spinand_probe,
> > +	.remove	= gen_spi_spinand_remove,
> > +};
> > +module_spi_driver(gen_spi_spinand_driver);
> > +
> > +MODULE_DESCRIPTION("Generic SPI controller to support SPI NAND");
> > +MODULE_AUTHOR("Peter Pan<peterpandong@micron.com>");
> > +MODULE_LICENSE("GPL v2");
> >   
> 
>
diff mbox

Patch

diff --git a/drivers/mtd/nand/spi/Kconfig b/drivers/mtd/nand/spi/Kconfig
index d77c46e..6bd1c65 100644
--- a/drivers/mtd/nand/spi/Kconfig
+++ b/drivers/mtd/nand/spi/Kconfig
@@ -3,3 +3,5 @@  menuconfig MTD_SPI_NAND
 	depends on MTD_NAND
 	help
 	  This is the framework for the SPI NAND device drivers.
+
+source "drivers/mtd/nand/spi/controllers/Kconfig"
diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
index df6c2ea..822e48d 100644
--- a/drivers/mtd/nand/spi/Makefile
+++ b/drivers/mtd/nand/spi/Makefile
@@ -1,2 +1,3 @@ 
 obj-$(CONFIG_MTD_SPI_NAND) += core.o
 obj-$(CONFIG_MTD_SPI_NAND) += micron.o
+obj-$(CONFIG_MTD_SPI_NAND) += controllers/
diff --git a/drivers/mtd/nand/spi/controllers/Kconfig b/drivers/mtd/nand/spi/controllers/Kconfig
new file mode 100644
index 0000000..8ab7023
--- /dev/null
+++ b/drivers/mtd/nand/spi/controllers/Kconfig
@@ -0,0 +1,5 @@ 
+config GENERIC_SPI_NAND
+	tristate "SPI NAND with generic SPI bus Support"
+	depends on MTD_SPI_NAND && SPI
+	help
+	  This is to support SPI NAND device with generic SPI bus.
diff --git a/drivers/mtd/nand/spi/controllers/Makefile b/drivers/mtd/nand/spi/controllers/Makefile
new file mode 100644
index 0000000..46cbf29
--- /dev/null
+++ b/drivers/mtd/nand/spi/controllers/Makefile
@@ -0,0 +1 @@ 
+obj-$(CONFIG_GENERIC_SPI_NAND) += generic-spi.o
diff --git a/drivers/mtd/nand/spi/controllers/generic-spi.c b/drivers/mtd/nand/spi/controllers/generic-spi.c
new file mode 100644
index 0000000..d354874
--- /dev/null
+++ b/drivers/mtd/nand/spi/controllers/generic-spi.c
@@ -0,0 +1,159 @@ 
+/*
+ * Copyright (c) 2009-2017 Micron Technology, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/mtd/spinand.h>
+
+struct gen_spi_spinand_controller {
+	struct spinand_controller ctrl;
+	struct spi_device *spi;
+};
+
+#define to_gen_spi_spinand_controller(c) \
+	container_of(c, struct gen_spi_spinand_controller, ctrl)
+
+/*
+ * gen_spi_spinand_exec_op - to process a command to send to the
+ * SPI NAND by generic SPI bus
+ * @chip: SPI NAND device structure
+ * @op: SPI NAND operation descriptor
+ */
+static int gen_spi_spinand_exec_op(struct spinand_device *chip,
+				   struct spinand_op *op)
+{
+	struct spi_message message;
+	struct spi_transfer x[3];
+	struct spinand_controller *scontroller = chip->controller.controller;
+	struct gen_spi_spinand_controller *controller;
+
+	controller = to_gen_spi_spinand_controller(scontroller);
+	spi_message_init(&message);
+	memset(x, 0, sizeof(x));
+	x[0].len = 1;
+	x[0].tx_nbits = 1;
+	x[0].tx_buf = &op->cmd;
+	spi_message_add_tail(&x[0], &message);
+
+	if (op->n_addr + op->dummy_bytes) {
+		x[1].len = op->n_addr + op->dummy_bytes;
+		x[1].tx_nbits = op->addr_nbits;
+		x[1].tx_buf = op->addr;
+		spi_message_add_tail(&x[1], &message);
+	}
+	if (op->n_tx) {
+		x[2].len = op->n_tx;
+		x[2].tx_nbits = op->data_nbits;
+		x[2].tx_buf = op->tx_buf;
+		spi_message_add_tail(&x[2], &message);
+	} else if (op->n_rx) {
+		x[2].len = op->n_rx;
+		x[2].rx_nbits = op->data_nbits;
+		x[2].rx_buf = op->rx_buf;
+		spi_message_add_tail(&x[2], &message);
+	}
+	return spi_sync(controller->spi, &message);
+}
+
+static struct spinand_controller_ops gen_spi_spinand_ops = {
+	.exec_op = gen_spi_spinand_exec_op,
+};
+
+static int gen_spi_spinand_probe(struct spi_device *spi)
+{
+	struct spinand_device *chip;
+	struct gen_spi_spinand_controller *controller;
+	struct spinand_controller *spinand_controller;
+	struct device *dev = &spi->dev;
+	u16 mode = spi->mode;
+	int ret;
+
+	chip = spinand_alloc(dev);
+	if (IS_ERR(chip)) {
+		ret = PTR_ERR(chip);
+		goto err1;
+	}
+	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
+	if (!controller) {
+		ret = -ENOMEM;
+		goto err2;
+	}
+	controller->spi = spi;
+	spinand_controller = &controller->ctrl;
+	spinand_controller->ops = &gen_spi_spinand_ops;
+	spinand_controller->caps = SPINAND_CAP_RD_X1 | SPINAND_CAP_WR_X1;
+
+	if ((mode & SPI_RX_QUAD) && (mode & SPI_TX_QUAD))
+		spinand_controller->caps |= SPINAND_CAP_RD_QUAD;
+	if ((mode & SPI_RX_DUAL) && (mode & SPI_TX_DUAL))
+		spinand_controller->caps |= SPINAND_CAP_RD_DUAL;
+	if (mode & SPI_RX_QUAD)
+		spinand_controller->caps |= SPINAND_CAP_RD_X4;
+	if (mode & SPI_RX_DUAL)
+		spinand_controller->caps |= SPINAND_CAP_RD_X2;
+	if (mode & SPI_TX_QUAD)
+		spinand_controller->caps |= SPINAND_CAP_WR_QUAD |
+					    SPINAND_CAP_WR_X4;
+	if (mode & SPI_TX_DUAL)
+		spinand_controller->caps |= SPINAND_CAP_WR_DUAL |
+					    SPINAND_CAP_WR_X2;
+	chip->controller.controller = spinand_controller;
+	/*
+	 * generic spi controller doesn't have ecc capability,
+	 * so use on-die ecc.
+	 */
+	chip->ecc.type = SPINAND_ECC_ONDIE;
+	spi_set_drvdata(spi, chip);
+
+	ret = spinand_register(chip);
+	if (ret)
+		goto err3;
+
+	return 0;
+
+err3:
+	devm_kfree(dev, controller);
+err2:
+	spinand_free(chip);
+err1:
+	return ret;
+}
+
+static int gen_spi_spinand_remove(struct spi_device *spi)
+{
+	struct spinand_device *chip = spi_get_drvdata(spi);
+	struct spinand_controller *scontroller = chip->controller.controller;
+	struct gen_spi_spinand_controller *controller;
+
+	spinand_unregister(chip);
+	controller = to_gen_spi_spinand_controller(scontroller);
+	devm_kfree(&spi->dev, controller);
+	spinand_free(chip);
+
+	return 0;
+}
+
+static struct spi_driver gen_spi_spinand_driver = {
+	.driver = {
+		.name	= "generic_spinand",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= gen_spi_spinand_probe,
+	.remove	= gen_spi_spinand_remove,
+};
+module_spi_driver(gen_spi_spinand_driver);
+
+MODULE_DESCRIPTION("Generic SPI controller to support SPI NAND");
+MODULE_AUTHOR("Peter Pan<peterpandong@micron.com>");
+MODULE_LICENSE("GPL v2");