diff mbox

[RFC,v6,3/3] drivers: nvmem: Add Vybrid OCOTP support

Message ID 9593ca1f925aff20a6671262efd2f45e256ea676.1435574288.git.maitysanchayan@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sanchayan June 29, 2015, 11:22 a.m. UTC
The patch adds support for the On Chip One Time Programmable Peripheral
(OCOTP) on the Vybrid platform.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
---
 drivers/nvmem/Kconfig       |  10 ++
 drivers/nvmem/Makefile      |   2 +
 drivers/nvmem/vf610-ocotp.c | 250 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 262 insertions(+)
 create mode 100644 drivers/nvmem/vf610-ocotp.c

Comments

Stefan Wahren July 6, 2015, 10:16 a.m. UTC | #1
Hi Sanchayan,

> Sanchayan Maity <maitysanchayan@gmail.com> hat am 29. Juni 2015 um 13:22
> geschrieben:
>
>
> The patch adds support for the On Chip One Time Programmable Peripheral
> (OCOTP) on the Vybrid platform.

please provide a changelog in your cover letter and a new version after changes.

I think it's important to note that the driver only support read-only access.

>
> Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> ---
> drivers/nvmem/Kconfig | 10 ++
> drivers/nvmem/Makefile | 2 +
> drivers/nvmem/vf610-ocotp.c | 250 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 262 insertions(+)
> create mode 100644 drivers/nvmem/vf610-ocotp.c
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 17f1a57..84c830d 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -33,4 +33,14 @@ config NVMEM_SUNXI_SID
> This driver can also be built as a module. If so, the module
> will be called eeprom-sunxi-sid.
>
> +config NVMEM_VF610_OCOTP
> + tristate "VF610 SoCs OCOTP support"
> + depends on SOC_VF610
> + help
> + This is a driver for the 'OCOTP' available on various Vybrid
> + devices.

I don't know much about Vybrid. But this driver is specific for VF610, isn't it?

> +
> + This driver can also be built as a module. If so, the module
> + will be called nvmem-vf610-ocotp.
> +
> endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index cc46791..a9ed113 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -11,3 +11,5 @@ obj-$(CONFIG_QCOM_QFPROM) += nvmem_qfprom.o
> nvmem_qfprom-y := qfprom.o
> obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem-sunxi-sid.o
> nvmem-sunxi-sid-y := sunxi-sid.o
> +obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
> +nvmem-vf610-ocotp-y := vf610-ocotp.o
> diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c
> new file mode 100644
> index 0000000..b7a782c
> --- /dev/null
> +++ b/drivers/nvmem/vf610-ocotp.c
> @@ -0,0 +1,250 @@
> +/*
> + * Copyright (C) 2015 Sanchayan Maity <sanchayan.maity@toradex.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * 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/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +/* OCOTP Register Offsets */
> +#define OCOTP_CTRL_REG 0x00
> +#define OCOTP_CTRL_SET 0x04
> +#define OCOTP_CTRL_CLR 0x08
> +#define OCOTP_TIMING 0x10
> +#define OCOTP_DATA 0x20
> +#define OCOTP_READ_CTRL_REG 0x30
> +#define OCOTP_READ_FUSE_DATA 0x40
> +
> +/* OCOTP Register bits and masks */
> +#define OCOTP_CTRL_WR_UNLOCK 16
> +#define OCOTP_CTRL_WR_UNLOCK_KEY 0x3E77
> +#define OCOTP_CTRL_WR_UNLOCK_MASK 0xFFFF0000
> +#define OCOTP_CTRL_ADDR 0
> +#define OCOTP_CTRL_ADDR_MASK 0x7F
> +#define OCOTP_CTRL_RELOAD_SHADOWS (0x1 << 10)
> +#define OCOTP_CTRL_ERROR (0x1 << 9)
> +#define OCOTP_CTRL_BUSY (0x1 << 8)

You can use the BIT() macro here.

> +
> +#define OCOTP_TIMING_STROBE_READ 16
> +#define OCOTP_TIMING_STROBE_READ_MASK 0x003F0000
> +#define OCOTP_TIMING_RELAX 12
> +#define OCOTP_TIMING_RELAX_MASK 0x0000F000
> +#define OCOTP_TIMING_STROBE_PROG 0
> +#define OCOTP_TIMING_STROBE_PROG_MASK 0x00000FFF
> +
> +#define OCOTP_READ_CTRL_READ_FUSE 0x1
> +
> +#define VF610_OCOTP_TIMEOUT 100000
> +
> +#define BF(value, field) (((value) << field) & field##_MASK)
> +
> +#define DEF_RELAX 20
> +
> +struct vf610_ocotp_dev {
> + void __iomem *base;
> + struct clk *clk;
> + struct device *dev;
> + struct resource *res;
> + struct regmap *regmap;
> + struct nvmem_device *nvmem;
> +};

Some member of this struct seems unnecessary to me. Please
remove the unused one.

> +
> +static int ocotp_timing;

How about storing the timings in struct above?

> +
> +static u8 valid_fuse_addr[] = {
> + 0x00, 0x01, 0x02, 0x04, 0x0F, 0x20, 0x21, 0x22, 0x23, 0x24,
> + 0x25, 0x26, 0x27, 0x28, 0x2F, 0x38, 0x39, 0x3A, 0x3B, 0x3C,
> + 0x3D, 0x3E, 0x3F
> +};

const?

> +
> +static int vf610_ocotp_wait_busy(void __iomem *base)
> +{
> + int timeout = VF610_OCOTP_TIMEOUT;
> +
> + while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
> + udelay(10);
> +
> + if (!timeout) {
> + writel(OCOTP_CTRL_ERROR, base + OCOTP_CTRL_CLR);
> + return -ETIMEDOUT;
> + }
> +
> + udelay(10);
> +
> + return 0;
> +}
> +
> +static int vf610_ocotp_calculate_timing(struct vf610_ocotp_dev *ocotp_dev)
> +{
> + u32 clk_rate;
> + u32 relax, strobe_read, strobe_prog;
> + u32 timing;
> +
> + clk_rate = clk_get_rate(ocotp_dev->clk);

If clk_get_rate() fails, then we should abort with a warning.

> +
> + relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
> + strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
> + strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;

A little explanation of the calculation would be helpful.

> +
> + timing = BF(relax, OCOTP_TIMING_RELAX);
> + timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
> + timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
> +
> + return timing;
> +}
> +
> +static int vf610_ocotp_set_timing(void __iomem *base, int timing)
> +{
> + writel(timing, base + OCOTP_TIMING);
> +
> + return 0;
> +}
> +
> +static int vf610_ocotp_write(void *context, const void *data, size_t count)
> +{
> + return 0;
> +}
> +
> +static int vf610_ocotp_read(void *context,
> + const void *offset, size_t reg_size,
> + void *val, size_t val_size)
> +{
> + void __iomem *ocotp_base = context;
> + u32 *buf = val;
> + u32 reg;
> + int ret;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(valid_fuse_addr); i++) {
> + vf610_ocotp_set_timing(ocotp_base, ocotp_timing);
> + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> + if (ret)
> + return ret;

Is it really necessary to set the timing in the loop, instead before?

> +
> + reg = readl(ocotp_base + OCOTP_CTRL_REG);
> + reg &= ~OCOTP_CTRL_ADDR_MASK;
> + reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
> + reg |= BF(valid_fuse_addr[i], OCOTP_CTRL_ADDR);
> + writel(reg, ocotp_base + OCOTP_CTRL_REG);
> +
> + writel(OCOTP_READ_CTRL_READ_FUSE,
> + ocotp_base + OCOTP_READ_CTRL_REG);
> + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> + if (ret)
> + return ret;
> +
> + if (readl(ocotp_base) & OCOTP_CTRL_ERROR) {
> + pr_err("Error reading from fuse address %d\n",
> + valid_fuse_addr[i]);

You could use dev_err() when storing vf610_ocotp_dev in the context.

> + writel(OCOTP_CTRL_ERROR, ocotp_base + OCOTP_CTRL_CLR);

Shouldn't the function abort here?

> + }
> +
> + *buf++ = readl(ocotp_base + OCOTP_READ_FUSE_DATA);
> + }
> +
> + return 0;
> +}
> +
> +static struct regmap_bus vf610_ocotp_bus = {
> + .read = vf610_ocotp_read,
> + .write = vf610_ocotp_write,
> + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> + .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static struct regmap_config ocotp_regmap_config = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> +};
> +
> +static struct nvmem_config ocotp_config = {
> + .name = "ocotp",
> + .owner = THIS_MODULE,
> +};
> +
> +static const struct of_device_id ocotp_of_match[] = {
> + { .compatible = "fsl,vf610-ocotp",},
> + {/* sentinel */},
> +};
> +MODULE_DEVICE_TABLE(of, ocotp_of_match);
> +
> +static int vf610_ocotp_remove(struct platform_device *pdev)
> +{
> + struct vf610_ocotp_dev *ocotp_dev = platform_get_drvdata(pdev);
> +
> + return nvmem_unregister(ocotp_dev->nvmem);
> +}
> +
> +static int vf610_ocotp_probe(struct platform_device *pdev)
> +{
> + struct vf610_ocotp_dev *ocotp_dev;
> +
> + ocotp_dev = devm_kzalloc(&pdev->dev,
> + sizeof(struct vf610_ocotp_dev), GFP_KERNEL);
> + if (!ocotp_dev)
> + return -ENOMEM;
> +
> + ocotp_dev->dev = &pdev->dev;
> +
> + ocotp_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + ocotp_dev->base = devm_ioremap_resource(ocotp_dev->dev, ocotp_dev->res);
> + if (IS_ERR(ocotp_dev->base))
> + return PTR_ERR(ocotp_dev->base);
> +
> + ocotp_dev->clk = devm_clk_get(ocotp_dev->dev, "ocotp");
> + if (IS_ERR(ocotp_dev->clk)) {
> + dev_err(ocotp_dev->dev, "failed getting clock, err = %ld\n",
> + PTR_ERR(ocotp_dev->clk));
> + return PTR_ERR(ocotp_dev->clk);
> + }
> +
> + ocotp_regmap_config.max_register = resource_size(ocotp_dev->res) - 1;

Looking at valid_fuse_addr shows me 0x3F as last valid register. So the rest
of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access could be
uninitializied.

Regards
Stefan
Sanchayan July 7, 2015, 5:19 a.m. UTC | #2
Hello Stefan,

On 15-07-06 12:16:34, Stefan Wahren wrote:
> Hi Sanchayan,
> 
> > Sanchayan Maity <maitysanchayan@gmail.com> hat am 29. Juni 2015 um 13:22
> > geschrieben:
> >
> >
> > The patch adds support for the On Chip One Time Programmable Peripheral
> > (OCOTP) on the Vybrid platform.
> 
> please provide a changelog in your cover letter and a new version after changes.
> 
> I think it's important to note that the driver only support read-only access.

Ok. Will mention this explicitly in the next version.

> 
> >
> > Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
> > ---
> > drivers/nvmem/Kconfig | 10 ++
> > drivers/nvmem/Makefile | 2 +
> > drivers/nvmem/vf610-ocotp.c | 250 ++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 262 insertions(+)
> > create mode 100644 drivers/nvmem/vf610-ocotp.c
> >
> > diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> > index 17f1a57..84c830d 100644
> > --- a/drivers/nvmem/Kconfig
> > +++ b/drivers/nvmem/Kconfig
> > @@ -33,4 +33,14 @@ config NVMEM_SUNXI_SID
> > This driver can also be built as a module. If so, the module
> > will be called eeprom-sunxi-sid.
> >
> > +config NVMEM_VF610_OCOTP
> > + tristate "VF610 SoCs OCOTP support"
> > + depends on SOC_VF610
> > + help
> > + This is a driver for the 'OCOTP' available on various Vybrid
> > + devices.
> 
> I don't know much about Vybrid. But this driver is specific for VF610, isn't it?

Sorry. I only checked on VF50 and VF61. Will check if is it available with the
other Vybrid devices and change if it is not so.

> 
> > +
> > + This driver can also be built as a module. If so, the module
> > + will be called nvmem-vf610-ocotp.
> > +
> > endif
> > diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> > index cc46791..a9ed113 100644
> > --- a/drivers/nvmem/Makefile
> > +++ b/drivers/nvmem/Makefile
> > @@ -11,3 +11,5 @@ obj-$(CONFIG_QCOM_QFPROM) += nvmem_qfprom.o
> > nvmem_qfprom-y := qfprom.o
> > obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem-sunxi-sid.o
> > nvmem-sunxi-sid-y := sunxi-sid.o
> > +obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
> > +nvmem-vf610-ocotp-y := vf610-ocotp.o
> > diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c
> > new file mode 100644
> > index 0000000..b7a782c
> > --- /dev/null
> > +++ b/drivers/nvmem/vf610-ocotp.c
> > @@ -0,0 +1,250 @@
> > +/*
> > + * Copyright (C) 2015 Sanchayan Maity <sanchayan.maity@toradex.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 and
> > + * only version 2 as published by the Free Software Foundation.
> > + *
> > + * 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/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/nvmem-provider.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +
> > +/* OCOTP Register Offsets */
> > +#define OCOTP_CTRL_REG 0x00
> > +#define OCOTP_CTRL_SET 0x04
> > +#define OCOTP_CTRL_CLR 0x08
> > +#define OCOTP_TIMING 0x10
> > +#define OCOTP_DATA 0x20
> > +#define OCOTP_READ_CTRL_REG 0x30
> > +#define OCOTP_READ_FUSE_DATA 0x40
> > +
> > +/* OCOTP Register bits and masks */
> > +#define OCOTP_CTRL_WR_UNLOCK 16
> > +#define OCOTP_CTRL_WR_UNLOCK_KEY 0x3E77
> > +#define OCOTP_CTRL_WR_UNLOCK_MASK 0xFFFF0000
> > +#define OCOTP_CTRL_ADDR 0
> > +#define OCOTP_CTRL_ADDR_MASK 0x7F
> > +#define OCOTP_CTRL_RELOAD_SHADOWS (0x1 << 10)
> > +#define OCOTP_CTRL_ERROR (0x1 << 9)
> > +#define OCOTP_CTRL_BUSY (0x1 << 8)
> 
> You can use the BIT() macro here.

Ok.

> 
> > +
> > +#define OCOTP_TIMING_STROBE_READ 16
> > +#define OCOTP_TIMING_STROBE_READ_MASK 0x003F0000
> > +#define OCOTP_TIMING_RELAX 12
> > +#define OCOTP_TIMING_RELAX_MASK 0x0000F000
> > +#define OCOTP_TIMING_STROBE_PROG 0
> > +#define OCOTP_TIMING_STROBE_PROG_MASK 0x00000FFF
> > +
> > +#define OCOTP_READ_CTRL_READ_FUSE 0x1
> > +
> > +#define VF610_OCOTP_TIMEOUT 100000
> > +
> > +#define BF(value, field) (((value) << field) & field##_MASK)
> > +
> > +#define DEF_RELAX 20
> > +
> > +struct vf610_ocotp_dev {
> > + void __iomem *base;
> > + struct clk *clk;
> > + struct device *dev;
> > + struct resource *res;
> > + struct regmap *regmap;
> > + struct nvmem_device *nvmem;
> > +};
> 
> Some member of this struct seems unnecessary to me. Please
> remove the unused one.
> 
> > +
> > +static int ocotp_timing;
> 
> How about storing the timings in struct above?

Ok.

> 
> > +
> > +static u8 valid_fuse_addr[] = {
> > + 0x00, 0x01, 0x02, 0x04, 0x0F, 0x20, 0x21, 0x22, 0x23, 0x24,
> > + 0x25, 0x26, 0x27, 0x28, 0x2F, 0x38, 0x39, 0x3A, 0x3B, 0x3C,
> > + 0x3D, 0x3E, 0x3F
> > +};
> 
> const?

Right.

> 
> > +
> > +static int vf610_ocotp_wait_busy(void __iomem *base)
> > +{
> > + int timeout = VF610_OCOTP_TIMEOUT;
> > +
> > + while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
> > + udelay(10);
> > +
> > + if (!timeout) {
> > + writel(OCOTP_CTRL_ERROR, base + OCOTP_CTRL_CLR);
> > + return -ETIMEDOUT;
> > + }
> > +
> > + udelay(10);
> > +
> > + return 0;
> > +}
> > +
> > +static int vf610_ocotp_calculate_timing(struct vf610_ocotp_dev *ocotp_dev)
> > +{
> > + u32 clk_rate;
> > + u32 relax, strobe_read, strobe_prog;
> > + u32 timing;
> > +
> > + clk_rate = clk_get_rate(ocotp_dev->clk);
> 
> If clk_get_rate() fails, then we should abort with a warning.

Correct. Will fix this.

> 
> > +
> > + relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
> > + strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
> > + strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
> 
> A little explanation of the calculation would be helpful.

Ok. Will add the relevant comments.

For now just to be clear, this is taken from from Barebox and as per Section 35.3.2.
DEF_RELAX is defined to be 20 as tRELAX is expected to be greated than 16.2ns with
the first primary equation being

tRELAX = tHP_PG = (OCOTP_TIMING[RELAX]+1)/ipg_frequency > 16.2ns

The rest of the equations follow the relax value defined.

> 
> > +
> > + timing = BF(relax, OCOTP_TIMING_RELAX);
> > + timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
> > + timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
> > +
> > + return timing;
> > +}
> > +
> > +static int vf610_ocotp_set_timing(void __iomem *base, int timing)
> > +{
> > + writel(timing, base + OCOTP_TIMING);
> > +
> > + return 0;
> > +}
> > +
> > +static int vf610_ocotp_write(void *context, const void *data, size_t count)
> > +{
> > + return 0;
> > +}
> > +
> > +static int vf610_ocotp_read(void *context,
> > + const void *offset, size_t reg_size,
> > + void *val, size_t val_size)
> > +{
> > + void __iomem *ocotp_base = context;
> > + u32 *buf = val;
> > + u32 reg;
> > + int ret;
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(valid_fuse_addr); i++) {
> > + vf610_ocotp_set_timing(ocotp_base, ocotp_timing);
> > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > + if (ret)
> > + return ret;
> 
> Is it really necessary to set the timing in the loop, instead before?

I will test it once. From my understanding of 35.3.1.5 I thought the timing
needs to explicitly programmed on every read. Perhaps I took it too literally.

> 
> > +
> > + reg = readl(ocotp_base + OCOTP_CTRL_REG);
> > + reg &= ~OCOTP_CTRL_ADDR_MASK;
> > + reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
> > + reg |= BF(valid_fuse_addr[i], OCOTP_CTRL_ADDR);
> > + writel(reg, ocotp_base + OCOTP_CTRL_REG);
> > +
> > + writel(OCOTP_READ_CTRL_READ_FUSE,
> > + ocotp_base + OCOTP_READ_CTRL_REG);
> > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > + if (ret)
> > + return ret;
> > +
> > + if (readl(ocotp_base) & OCOTP_CTRL_ERROR) {
> > + pr_err("Error reading from fuse address %d\n",
> > + valid_fuse_addr[i]);
> 
> You could use dev_err() when storing vf610_ocotp_dev in the context.

Ok.

> 
> > + writel(OCOTP_CTRL_ERROR, ocotp_base + OCOTP_CTRL_CLR);
> 
> Shouldn't the function abort here?

I am not sure about what usage I should follow here. I went for an
explicit error message and since 0xBADABADA is expected to be returned
on a read locked shadow register, the user would get the above for this
particular fuse address and the rest can still be valid since the TRM
mentions "subsequent reads to unlocked shadow locations will still work
successfully." So I did not abort on the error. Should I?

> 
> > + }
> > +
> > + *buf++ = readl(ocotp_base + OCOTP_READ_FUSE_DATA);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct regmap_bus vf610_ocotp_bus = {
> > + .read = vf610_ocotp_read,
> > + .write = vf610_ocotp_write,
> > + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> > + .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> > +};
> > +
> > +static struct regmap_config ocotp_regmap_config = {
> > + .reg_bits = 32,
> > + .val_bits = 32,
> > + .reg_stride = 4,
> > +};
> > +
> > +static struct nvmem_config ocotp_config = {
> > + .name = "ocotp",
> > + .owner = THIS_MODULE,
> > +};
> > +
> > +static const struct of_device_id ocotp_of_match[] = {
> > + { .compatible = "fsl,vf610-ocotp",},
> > + {/* sentinel */},
> > +};
> > +MODULE_DEVICE_TABLE(of, ocotp_of_match);
> > +
> > +static int vf610_ocotp_remove(struct platform_device *pdev)
> > +{
> > + struct vf610_ocotp_dev *ocotp_dev = platform_get_drvdata(pdev);
> > +
> > + return nvmem_unregister(ocotp_dev->nvmem);
> > +}
> > +
> > +static int vf610_ocotp_probe(struct platform_device *pdev)
> > +{
> > + struct vf610_ocotp_dev *ocotp_dev;
> > +
> > + ocotp_dev = devm_kzalloc(&pdev->dev,
> > + sizeof(struct vf610_ocotp_dev), GFP_KERNEL);
> > + if (!ocotp_dev)
> > + return -ENOMEM;
> > +
> > + ocotp_dev->dev = &pdev->dev;
> > +
> > + ocotp_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > + ocotp_dev->base = devm_ioremap_resource(ocotp_dev->dev, ocotp_dev->res);
> > + if (IS_ERR(ocotp_dev->base))
> > + return PTR_ERR(ocotp_dev->base);
> > +
> > + ocotp_dev->clk = devm_clk_get(ocotp_dev->dev, "ocotp");
> > + if (IS_ERR(ocotp_dev->clk)) {
> > + dev_err(ocotp_dev->dev, "failed getting clock, err = %ld\n",
> > + PTR_ERR(ocotp_dev->clk));
> > + return PTR_ERR(ocotp_dev->clk);
> > + }
> > +
> > + ocotp_regmap_config.max_register = resource_size(ocotp_dev->res) - 1;
> 
> Looking at valid_fuse_addr shows me 0x3F as last valid register. So the rest
> of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access could be
> uninitializied.

Sorry I did not exactly get you here. The intention behind using the valid_fuse_addr
is to allow reading only from valid fuse addresses and avoid reading from all other
locations as per the Fuse map address table 35-1.

Thanks for the review.

Regards,
Sanchayan.
Stefan Wahren July 7, 2015, 12:49 p.m. UTC | #3
Hi Sanchayan,

> maitysanchayan@gmail.com hat am 7. Juli 2015 um 07:19 geschrieben:
>
>
> [...]
> > > diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> > > index 17f1a57..84c830d 100644
> > > --- a/drivers/nvmem/Kconfig
> > > +++ b/drivers/nvmem/Kconfig
> > > @@ -33,4 +33,14 @@ config NVMEM_SUNXI_SID
> > > This driver can also be built as a module. If so, the module
> > > will be called eeprom-sunxi-sid.
> > >
> > > +config NVMEM_VF610_OCOTP
> > > + tristate "VF610 SoCs OCOTP support"
> > > + depends on SOC_VF610
> > > + help
> > > + This is a driver for the 'OCOTP' available on various Vybrid
> > > + devices.
> >
> > I don't know much about Vybrid. But this driver is specific for VF610, isn't
> > it?
>
> Sorry. I only checked on VF50 and VF61. Will check if is it available with the
> other Vybrid devices and change if it is not so.

no problem. If you spend time in testing your driver with different devices, you
could mention
this in your patch description. The naming VF610 suggests that the driver is
very specific.
That confuses me a little bit.

>
> >
> > > +
> > > +
> > > +static int vf610_ocotp_write(void *context, const void *data, size_t
> > > count)
> > > +{
> > > + return 0;
> > > +}
> > > +
> > > +static int vf610_ocotp_read(void *context,
> > > + const void *offset, size_t reg_size,
> > > + void *val, size_t val_size)
> > > +{
> > > + void __iomem *ocotp_base = context;
> > > + u32 *buf = val;
> > > + u32 reg;
> > > + int ret;
> > > + int i;
> > > +
> > > + for (i = 0; i < ARRAY_SIZE(valid_fuse_addr); i++) {
> > > + vf610_ocotp_set_timing(ocotp_base, ocotp_timing);
> > > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > > + if (ret)
> > > + return ret;
> >
> > Is it really necessary to set the timing in the loop, instead before?
>
> I will test it once. From my understanding of 35.3.1.5 I thought the timing
> needs to explicitly programmed on every read. Perhaps I took it too literally.

It was only a question. If barebox does the same, it should be okay.

>
> >
> > > +
> > > + reg = readl(ocotp_base + OCOTP_CTRL_REG);
> > > + reg &= ~OCOTP_CTRL_ADDR_MASK;
> > > + reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
> > > + reg |= BF(valid_fuse_addr[i], OCOTP_CTRL_ADDR);
> > > + writel(reg, ocotp_base + OCOTP_CTRL_REG);
> > > +
> > > + writel(OCOTP_READ_CTRL_READ_FUSE,
> > > + ocotp_base + OCOTP_READ_CTRL_REG);
> > > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + if (readl(ocotp_base) & OCOTP_CTRL_ERROR) {
> > > + pr_err("Error reading from fuse address %d\n",
> > > + valid_fuse_addr[i]);
> >
> > You could use dev_err() when storing vf610_ocotp_dev in the context.
>
> Ok.
>
> >
> > > + writel(OCOTP_CTRL_ERROR, ocotp_base + OCOTP_CTRL_CLR);
> >
> > Shouldn't the function abort here?
>
> I am not sure about what usage I should follow here. I went for an
> explicit error message and since 0xBADABADA is expected to be returned
> on a read locked shadow register, the user would get the above for this
> particular fuse address and the rest can still be valid since the TRM
> mentions "subsequent reads to unlocked shadow locations will still work
> successfully." So I did not abort on the error. Should I?

In case you don't want to abort, a comment about the 0xBADABADA behavior would
be helpful.

>
> >
> > > +
> > > +
> > > +static int vf610_ocotp_probe(struct platform_device *pdev)
> > > +{
> > > + struct vf610_ocotp_dev *ocotp_dev;
> > > +
> > > + ocotp_dev = devm_kzalloc(&pdev->dev,
> > > + sizeof(struct vf610_ocotp_dev), GFP_KERNEL);
> > > + if (!ocotp_dev)
> > > + return -ENOMEM;
> > > +
> > > + ocotp_dev->dev = &pdev->dev;
> > > +
> > > + ocotp_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > + ocotp_dev->base = devm_ioremap_resource(ocotp_dev->dev, ocotp_dev->res);
> > > + if (IS_ERR(ocotp_dev->base))
> > > + return PTR_ERR(ocotp_dev->base);
> > > +
> > > + ocotp_dev->clk = devm_clk_get(ocotp_dev->dev, "ocotp");
> > > + if (IS_ERR(ocotp_dev->clk)) {
> > > + dev_err(ocotp_dev->dev, "failed getting clock, err = %ld\n",
> > > + PTR_ERR(ocotp_dev->clk));
> > > + return PTR_ERR(ocotp_dev->clk);
> > > + }
> > > +
> > > + ocotp_regmap_config.max_register = resource_size(ocotp_dev->res) - 1;
> >
> > Looking at valid_fuse_addr shows me 0x3F as last valid register. So the rest
> > of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access
> > could be
> > uninitializied.
>
> Sorry I did not exactly get you here. The intention behind using the
> valid_fuse_addr
> is to allow reading only from valid fuse addresses and avoid reading from all
> other
> locations as per the Fuse map address table 35-1.

Yes, i got your intention. But from my unterstand the read function should fill
up
the complete buffer with defined values. My MXS OCOTP driver have the same
problem
and fill up the invalid registers with zero.

Regards
Stefan

>
> Thanks for the review.
>
> Regards,
> Sanchayan.
Sanchayan July 8, 2015, 5:39 a.m. UTC | #4
Hi Stefan,

On 15-07-07 14:49:06, Stefan Wahren wrote:
> Hi Sanchayan,
> 
> > maitysanchayan@gmail.com hat am 7. Juli 2015 um 07:19 geschrieben:
> >
> >
> > [...]
> > > > diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> > > > index 17f1a57..84c830d 100644
> > > > --- a/drivers/nvmem/Kconfig
> > > > +++ b/drivers/nvmem/Kconfig
> > > > @@ -33,4 +33,14 @@ config NVMEM_SUNXI_SID
> > > > This driver can also be built as a module. If so, the module
> > > > will be called eeprom-sunxi-sid.
> > > >
> > > > +config NVMEM_VF610_OCOTP
> > > > + tristate "VF610 SoCs OCOTP support"
> > > > + depends on SOC_VF610
> > > > + help
> > > > + This is a driver for the 'OCOTP' available on various Vybrid
> > > > + devices.
> > >
> > > I don't know much about Vybrid. But this driver is specific for VF610, isn't
> > > it?
> >
> > Sorry. I only checked on VF50 and VF61. Will check if is it available with the
> > other Vybrid devices and change if it is not so.
> 
> no problem. If you spend time in testing your driver with different devices, you
> could mention
> this in your patch description. The naming VF610 suggests that the driver is
> very specific.
> That confuses me a little bit.

Sorry about that. Will add the necessary information in the next respin for sure.

> 
> >
> > >
> > > > +
> > > > +
> > > > +static int vf610_ocotp_write(void *context, const void *data, size_t
> > > > count)
> > > > +{
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static int vf610_ocotp_read(void *context,
> > > > + const void *offset, size_t reg_size,
> > > > + void *val, size_t val_size)
> > > > +{
> > > > + void __iomem *ocotp_base = context;
> > > > + u32 *buf = val;
> > > > + u32 reg;
> > > > + int ret;
> > > > + int i;
> > > > +
> > > > + for (i = 0; i < ARRAY_SIZE(valid_fuse_addr); i++) {
> > > > + vf610_ocotp_set_timing(ocotp_base, ocotp_timing);
> > > > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > > > + if (ret)
> > > > + return ret;
> > >
> > > Is it really necessary to set the timing in the loop, instead before?
> >
> > I will test it once. From my understanding of 35.3.1.5 I thought the timing
> > needs to explicitly programmed on every read. Perhaps I took it too literally.
> 
> It was only a question. If barebox does the same, it should be okay.
>

Yes, the code logic is completely similar to barebox except for changes like
how timeout is handled here in the wait busy function.

> >
> > >
> > > > +
> > > > + reg = readl(ocotp_base + OCOTP_CTRL_REG);
> > > > + reg &= ~OCOTP_CTRL_ADDR_MASK;
> > > > + reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
> > > > + reg |= BF(valid_fuse_addr[i], OCOTP_CTRL_ADDR);
> > > > + writel(reg, ocotp_base + OCOTP_CTRL_REG);
> > > > +
> > > > + writel(OCOTP_READ_CTRL_READ_FUSE,
> > > > + ocotp_base + OCOTP_READ_CTRL_REG);
> > > > + ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + if (readl(ocotp_base) & OCOTP_CTRL_ERROR) {
> > > > + pr_err("Error reading from fuse address %d\n",
> > > > + valid_fuse_addr[i]);
> > >
> > > You could use dev_err() when storing vf610_ocotp_dev in the context.
> >
> > Ok.
> >
> > >
> > > > + writel(OCOTP_CTRL_ERROR, ocotp_base + OCOTP_CTRL_CLR);
> > >
> > > Shouldn't the function abort here?
> >
> > I am not sure about what usage I should follow here. I went for an
> > explicit error message and since 0xBADABADA is expected to be returned
> > on a read locked shadow register, the user would get the above for this
> > particular fuse address and the rest can still be valid since the TRM
> > mentions "subsequent reads to unlocked shadow locations will still work
> > successfully." So I did not abort on the error. Should I?
> 
> In case you don't want to abort, a comment about the 0xBADABADA behavior would
> be helpful.

Ok. Will add the same.

> 
> >
> > >
> > > > +
> > > > +
> > > > +static int vf610_ocotp_probe(struct platform_device *pdev)
> > > > +{
> > > > + struct vf610_ocotp_dev *ocotp_dev;
> > > > +
> > > > + ocotp_dev = devm_kzalloc(&pdev->dev,
> > > > + sizeof(struct vf610_ocotp_dev), GFP_KERNEL);
> > > > + if (!ocotp_dev)
> > > > + return -ENOMEM;
> > > > +
> > > > + ocotp_dev->dev = &pdev->dev;
> > > > +
> > > > + ocotp_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > > + ocotp_dev->base = devm_ioremap_resource(ocotp_dev->dev, ocotp_dev->res);
> > > > + if (IS_ERR(ocotp_dev->base))
> > > > + return PTR_ERR(ocotp_dev->base);
> > > > +
> > > > + ocotp_dev->clk = devm_clk_get(ocotp_dev->dev, "ocotp");
> > > > + if (IS_ERR(ocotp_dev->clk)) {
> > > > + dev_err(ocotp_dev->dev, "failed getting clock, err = %ld\n",
> > > > + PTR_ERR(ocotp_dev->clk));
> > > > + return PTR_ERR(ocotp_dev->clk);
> > > > + }
> > > > +
> > > > + ocotp_regmap_config.max_register = resource_size(ocotp_dev->res) - 1;
> > >
> > > Looking at valid_fuse_addr shows me 0x3F as last valid register. So the rest
> > > of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access
> > > could be
> > > uninitializied.
> >
> > Sorry I did not exactly get you here. The intention behind using the
> > valid_fuse_addr
> > is to allow reading only from valid fuse addresses and avoid reading from all
> > other
> > locations as per the Fuse map address table 35-1.
> 
> Yes, i got your intention. But from my unterstand the read function should fill
> up
> the complete buffer with defined values. My MXS OCOTP driver have the same
> problem
> and fill up the invalid registers with zero.

I must admit I had not thought of that. Thats a valid point. I dont know at the
moment however what would be the correct approach here. Perhaps filling locations
other than the valid fuse addresses as per the fuse map table with 0xBADABADA is
the right thing? Anyways that's what is going to be returned if we were to read
a location which is read locked or reserved.

However since the fuse address and base address mapping is not exactly linear,
this would require some additional logic than the simple thing I did. Also OCOTP
requires the fuse address to be written. May be using the nvmem consumer DT property
gets something?! Not sure atm.

- Sanchayan.
Stefan Wahren July 8, 2015, 8:55 p.m. UTC | #5
Hi Sanchayan,

> maitysanchayan@gmail.com hat am 8. Juli 2015 um 07:39 geschrieben:
>
>
> [...]
> > > >
> > > > Looking at valid_fuse_addr shows me 0x3F as last valid register. So the
> > > > rest
> > > > of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access
> > > > could be
> > > > uninitializied.
> > >
> > > Sorry I did not exactly get you here. The intention behind using the
> > > valid_fuse_addr
> > > is to allow reading only from valid fuse addresses and avoid reading from
> > > all
> > > other
> > > locations as per the Fuse map address table 35-1.
> >
> > Yes, i got your intention. But from my unterstand the read function should
> > fill
> > up
> > the complete buffer with defined values. My MXS OCOTP driver have the same
> > problem
> > and fill up the invalid registers with zero.
>
> I must admit I had not thought of that. Thats a valid point. I dont know at
> the
> moment however what would be the correct approach here. Perhaps filling
> locations
> other than the valid fuse addresses as per the fuse map table with 0xBADABADA
> is
> the right thing? Anyways that's what is going to be returned if we were to
> read
> a location which is read locked or reserved.

since we are operating in userspace the behavior shouldn't be specific to the
device.
It would be good when all drivers behave the same. But i think it would be much
better
as the nvmem framework take care of it and preinit the buffer with a defined
value.

>
> However since the fuse address and base address mapping is not exactly linear,
> this would require some additional logic than the simple thing I did. 

I defined a regmap_access_table for valid read registers in my case. But i think
in your case
an implementation of the readable_reg callback in the regmap_config would be
more elegant.

You can validate your implementation under /sys/kernel/debug/regmap/

Sorry, i'm a newbie to regmap.

Stefan

> Also OCOTP requires the fuse address to be written. May be using the nvmem
> consumer DT property
> gets something?! Not sure atm.
>
> - Sanchayan.
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Sanchayan July 10, 2015, 6:09 p.m. UTC | #6
Hello Stefan,

On 15-07-08 22:55:23, Stefan Wahren wrote:
> Hi Sanchayan,
> 
> > maitysanchayan@gmail.com hat am 8. Juli 2015 um 07:39 geschrieben:
> >
> >
> > [...]
> > > > >
> > > > > Looking at valid_fuse_addr shows me 0x3F as last valid register. So the
> > > > > rest
> > > > > of the buffer ( 0xD00 - sizeof(valid_fuse_addr) ) in case of raw access
> > > > > could be
> > > > > uninitializied.
> > > >
> > > > Sorry I did not exactly get you here. The intention behind using the
> > > > valid_fuse_addr
> > > > is to allow reading only from valid fuse addresses and avoid reading from
> > > > all
> > > > other
> > > > locations as per the Fuse map address table 35-1.
> > >
> > > Yes, i got your intention. But from my unterstand the read function should
> > > fill
> > > up
> > > the complete buffer with defined values. My MXS OCOTP driver have the same
> > > problem
> > > and fill up the invalid registers with zero.
> >
> > I must admit I had not thought of that. Thats a valid point. I dont know at
> > the
> > moment however what would be the correct approach here. Perhaps filling
> > locations
> > other than the valid fuse addresses as per the fuse map table with 0xBADABADA
> > is
> > the right thing? Anyways that's what is going to be returned if we were to
> > read
> > a location which is read locked or reserved.
> 
> since we are operating in userspace the behavior shouldn't be specific to the
> device.
> It would be good when all drivers behave the same. But i think it would be much
> better
> as the nvmem framework take care of it and preinit the buffer with a defined
> value.

There is a v7 now. Yet to give that a try or look at it.

> 
> >
> > However since the fuse address and base address mapping is not exactly linear,
> > this would require some additional logic than the simple thing I did. 
> 
> I defined a regmap_access_table for valid read registers in my case. But i think
> in your case
> an implementation of the readable_reg callback in the regmap_config would be
> more elegant.
> 
> You can validate your implementation under /sys/kernel/debug/regmap/

Thank you for the input. I will have a look at it and give it a try.

> 
> Sorry, i'm a newbie to regmap.

Same here as well :)

Regards,
Sanchayan.
diff mbox

Patch

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 17f1a57..84c830d 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -33,4 +33,14 @@  config NVMEM_SUNXI_SID
 	  This driver can also be built as a module. If so, the module
 	  will be called eeprom-sunxi-sid.
 
+config NVMEM_VF610_OCOTP
+	tristate "VF610 SoCs OCOTP support"
+	depends on SOC_VF610
+	help
+	  This is a driver for the 'OCOTP' available on various Vybrid
+	  devices.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem-vf610-ocotp.
+
 endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index cc46791..a9ed113 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -11,3 +11,5 @@  obj-$(CONFIG_QCOM_QFPROM)	+= nvmem_qfprom.o
 nvmem_qfprom-y			:= qfprom.o
 obj-$(CONFIG_NVMEM_SUNXI_SID)	+= nvmem-sunxi-sid.o
 nvmem-sunxi-sid-y		:= sunxi-sid.o
+obj-$(CONFIG_NVMEM_VF610_OCOTP)	+= nvmem-vf610-ocotp.o
+nvmem-vf610-ocotp-y		:= vf610-ocotp.o
diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c
new file mode 100644
index 0000000..b7a782c
--- /dev/null
+++ b/drivers/nvmem/vf610-ocotp.c
@@ -0,0 +1,250 @@ 
+/*
+ * Copyright (C) 2015 Sanchayan Maity <sanchayan.maity@toradex.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/nvmem-provider.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* OCOTP Register Offsets */
+#define OCOTP_CTRL_REG          0x00
+#define OCOTP_CTRL_SET          0x04
+#define OCOTP_CTRL_CLR          0x08
+#define OCOTP_TIMING            0x10
+#define OCOTP_DATA              0x20
+#define OCOTP_READ_CTRL_REG     0x30
+#define OCOTP_READ_FUSE_DATA    0x40
+
+/* OCOTP Register bits and masks */
+#define OCOTP_CTRL_WR_UNLOCK         16
+#define OCOTP_CTRL_WR_UNLOCK_KEY     0x3E77
+#define OCOTP_CTRL_WR_UNLOCK_MASK    0xFFFF0000
+#define OCOTP_CTRL_ADDR              0
+#define OCOTP_CTRL_ADDR_MASK         0x7F
+#define OCOTP_CTRL_RELOAD_SHADOWS    (0x1 << 10)
+#define OCOTP_CTRL_ERROR             (0x1 << 9)
+#define OCOTP_CTRL_BUSY              (0x1 << 8)
+
+#define OCOTP_TIMING_STROBE_READ        16
+#define OCOTP_TIMING_STROBE_READ_MASK   0x003F0000
+#define OCOTP_TIMING_RELAX              12
+#define OCOTP_TIMING_RELAX_MASK         0x0000F000
+#define OCOTP_TIMING_STROBE_PROG        0
+#define OCOTP_TIMING_STROBE_PROG_MASK   0x00000FFF
+
+#define OCOTP_READ_CTRL_READ_FUSE    0x1
+
+#define VF610_OCOTP_TIMEOUT          100000
+
+#define BF(value, field)             (((value) << field) & field##_MASK)
+
+#define DEF_RELAX                    20
+
+struct vf610_ocotp_dev {
+	void __iomem *base;
+	struct clk *clk;
+	struct device *dev;
+	struct resource *res;
+	struct regmap *regmap;
+	struct nvmem_device *nvmem;
+};
+
+static int ocotp_timing;
+
+static u8 valid_fuse_addr[] = {
+	0x00, 0x01, 0x02, 0x04, 0x0F, 0x20, 0x21, 0x22, 0x23, 0x24,
+	0x25, 0x26, 0x27, 0x28, 0x2F, 0x38, 0x39, 0x3A, 0x3B, 0x3C,
+	0x3D, 0x3E, 0x3F
+};
+
+static int vf610_ocotp_wait_busy(void __iomem *base)
+{
+	int timeout = VF610_OCOTP_TIMEOUT;
+
+	while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
+		udelay(10);
+
+	if (!timeout) {
+		writel(OCOTP_CTRL_ERROR, base + OCOTP_CTRL_CLR);
+		return -ETIMEDOUT;
+	}
+
+	udelay(10);
+
+	return 0;
+}
+
+static int vf610_ocotp_calculate_timing(struct vf610_ocotp_dev *ocotp_dev)
+{
+	u32 clk_rate;
+	u32 relax, strobe_read, strobe_prog;
+	u32 timing;
+
+	clk_rate = clk_get_rate(ocotp_dev->clk);
+
+	relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
+	strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
+	strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
+
+	timing = BF(relax, OCOTP_TIMING_RELAX);
+	timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
+	timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
+
+	return timing;
+}
+
+static int vf610_ocotp_set_timing(void __iomem *base, int timing)
+{
+	writel(timing, base + OCOTP_TIMING);
+
+	return 0;
+}
+
+static int vf610_ocotp_write(void *context, const void *data, size_t count)
+{
+	return 0;
+}
+
+static int vf610_ocotp_read(void *context,
+					const void *offset, size_t reg_size,
+					void *val, size_t val_size)
+{
+	void __iomem *ocotp_base = context;
+	u32 *buf = val;
+	u32 reg;
+	int ret;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(valid_fuse_addr); i++) {
+		vf610_ocotp_set_timing(ocotp_base, ocotp_timing);
+		ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
+		if (ret)
+			return ret;
+
+		reg = readl(ocotp_base + OCOTP_CTRL_REG);
+		reg &= ~OCOTP_CTRL_ADDR_MASK;
+		reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
+		reg |= BF(valid_fuse_addr[i], OCOTP_CTRL_ADDR);
+		writel(reg, ocotp_base + OCOTP_CTRL_REG);
+
+		writel(OCOTP_READ_CTRL_READ_FUSE,
+			ocotp_base + OCOTP_READ_CTRL_REG);
+		ret = vf610_ocotp_wait_busy(ocotp_base + OCOTP_CTRL_REG);
+		if (ret)
+			return ret;
+
+		if (readl(ocotp_base) & OCOTP_CTRL_ERROR) {
+			pr_err("Error reading from fuse address %d\n",
+				valid_fuse_addr[i]);
+			writel(OCOTP_CTRL_ERROR, ocotp_base + OCOTP_CTRL_CLR);
+		}
+
+		*buf++ = readl(ocotp_base + OCOTP_READ_FUSE_DATA);
+	}
+
+	return 0;
+}
+
+static struct regmap_bus vf610_ocotp_bus = {
+	.read = vf610_ocotp_read,
+	.write = vf610_ocotp_write,
+	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static struct regmap_config ocotp_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static struct nvmem_config ocotp_config = {
+	.name = "ocotp",
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id ocotp_of_match[] = {
+	{ .compatible = "fsl,vf610-ocotp",},
+	{/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, ocotp_of_match);
+
+static int vf610_ocotp_remove(struct platform_device *pdev)
+{
+	struct vf610_ocotp_dev *ocotp_dev = platform_get_drvdata(pdev);
+
+	return nvmem_unregister(ocotp_dev->nvmem);
+}
+
+static int vf610_ocotp_probe(struct platform_device *pdev)
+{
+	struct vf610_ocotp_dev *ocotp_dev;
+
+	ocotp_dev = devm_kzalloc(&pdev->dev,
+			sizeof(struct vf610_ocotp_dev), GFP_KERNEL);
+	if (!ocotp_dev)
+		return -ENOMEM;
+
+	ocotp_dev->dev = &pdev->dev;
+
+	ocotp_dev->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ocotp_dev->base = devm_ioremap_resource(ocotp_dev->dev, ocotp_dev->res);
+	if (IS_ERR(ocotp_dev->base))
+		return PTR_ERR(ocotp_dev->base);
+
+	ocotp_dev->clk = devm_clk_get(ocotp_dev->dev, "ocotp");
+	if (IS_ERR(ocotp_dev->clk)) {
+		dev_err(ocotp_dev->dev, "failed getting clock, err = %ld\n",
+			PTR_ERR(ocotp_dev->clk));
+		return PTR_ERR(ocotp_dev->clk);
+	}
+
+	ocotp_regmap_config.max_register = resource_size(ocotp_dev->res) - 1;
+
+	ocotp_dev->regmap = devm_regmap_init(ocotp_dev->dev,
+		&vf610_ocotp_bus, ocotp_dev->base, &ocotp_regmap_config);
+	if (IS_ERR(ocotp_dev->regmap)) {
+		dev_err(ocotp_dev->dev, "regmap init failed\n");
+		return PTR_ERR(ocotp_dev->regmap);
+	}
+	ocotp_config.dev = ocotp_dev->dev;
+
+	ocotp_dev->nvmem = nvmem_register(&ocotp_config);
+	if (IS_ERR(ocotp_dev->nvmem))
+		return PTR_ERR(ocotp_dev->nvmem);
+
+	platform_set_drvdata(pdev, ocotp_dev);
+
+	ocotp_timing = vf610_ocotp_calculate_timing(ocotp_dev);
+
+	return 0;
+}
+
+static struct platform_driver vf610_ocotp_driver = {
+	.probe = vf610_ocotp_probe,
+	.remove = vf610_ocotp_remove,
+	.driver = {
+		.name = "vf610-ocotp",
+		.of_match_table = ocotp_of_match,
+	},
+};
+module_platform_driver(vf610_ocotp_driver);
+MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
+MODULE_DESCRIPTION("Vybrid OCOTP driver");
+MODULE_LICENSE("GPL v2");