[PATCH 0/2] nvmem: meson-efuse: add write support

[PATCH 0/2] nvmem: meson-efuse: add write support

[Jerome Brunet]

This changeset adds write support to meson efuse driver.
The first patch just changes the way the nvmem data are allocated w/o
any functional changes. The second patches actually adds write support.

The memory being an OTP, it is safer if it remains read-only by default,
which is why I also submitted this DT patch [0].

If a user knows what he is doing, it should be easy to remove the
read-only property from the board DT. This can be done in u-boot, before
starting linux:

 > fdt rm /efuse read-only

Tested on the gxl libretech-cc

[0]: https://lkml.kernel.org/r/20180316145021.8517-1-jbrunet@baylibre.com

Jerome Brunet (2):
  nvmem: meson-efuse: remove econfig global
  nvmem: meson-efuse: add write support

 drivers/nvmem/meson-efuse.c | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)

-- 
2.14.3

[PATCH 1/2] nvmem: meson-efuse: remove econfig global

[Jerome Brunet]

Having a global structure holding a reference to the device
structure is not very nice. Allocate the econfig instead and fill
the nvmem information as before

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/nvmem/meson-efuse.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c
index a43c68f90937..7ad80b80b293 100644
--- a/drivers/nvmem/meson-efuse.c
+++ b/drivers/nvmem/meson-efuse.c
@@ -35,13 +35,6 @@ static int meson_efuse_read(void *context, unsigned int offset,
 	return 0;
 }
 
-static struct nvmem_config econfig = {
-	.name = "meson-efuse",
-	.stride = 1,
-	.word_size = 1,
-	.read_only = true,
-};
-
 static const struct of_device_id meson_efuse_match[] = {
 	{ .compatible = "amlogic,meson-gxbb-efuse", },
 	{ /* sentinel */ },
@@ -50,17 +43,27 @@ MODULE_DEVICE_TABLE(of, meson_efuse_match);
 
 static int meson_efuse_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct nvmem_device *nvmem;
+	struct nvmem_config *econfig;
 	unsigned int size;
 
 	if (meson_sm_call(SM_EFUSE_USER_MAX, &size, 0, 0, 0, 0, 0) < 0)
 		return -EINVAL;
 
-	econfig.dev = &pdev->dev;
-	econfig.reg_read = meson_efuse_read;
-	econfig.size = size;
+	econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL);
+	if (!econfig)
+		return -ENOMEM;
+
+	econfig->dev = dev;
+	econfig->name = dev_name(dev);
+	econfig->stride = 1;
+	econfig->word_size = 1;
+	econfig->read_only = true;
+	econfig->reg_read = meson_efuse_read;
+	econfig->size = size;
 
-	nvmem = nvmem_register(&econfig);
+	nvmem = nvmem_register(econfig);
 	if (IS_ERR(nvmem))
 		return PTR_ERR(nvmem);
 
-- 
2.14.3

[PATCH 2/2] nvmem: meson-efuse: add write support

[Jerome Brunet]

Add write support to the meson-gx efuse driver.
Beware, this efuse is one time programmable !

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/nvmem/meson-efuse.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c
index 7ad80b80b293..30da5e1abf84 100644
--- a/drivers/nvmem/meson-efuse.c
+++ b/drivers/nvmem/meson-efuse.c
@@ -35,6 +35,20 @@ static int meson_efuse_read(void *context, unsigned int offset,
 	return 0;
 }
 
+static int meson_efuse_write(void *context, unsigned int offset,
+			     void *val, size_t bytes)
+{
+	u8 *buf = val;
+	int ret;
+
+	ret = meson_sm_call_write(buf, bytes, SM_EFUSE_WRITE, offset,
+				  bytes, 0, 0, 0);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static const struct of_device_id meson_efuse_match[] = {
 	{ .compatible = "amlogic,meson-gxbb-efuse", },
 	{ /* sentinel */ },
@@ -59,8 +73,8 @@ static int meson_efuse_probe(struct platform_device *pdev)
 	econfig->name = dev_name(dev);
 	econfig->stride = 1;
 	econfig->word_size = 1;
-	econfig->read_only = true;
 	econfig->reg_read = meson_efuse_read;
+	econfig->reg_write = meson_efuse_write;
 	econfig->size = size;
 
 	nvmem = nvmem_register(econfig);
-- 
2.14.3

Re: [PATCH 0/2] nvmem: meson-efuse: add write support

[Jerome Brunet]

On Fri, 2018-03-16 at 16:01 +0100, Jerome Brunet wrote:
> This changeset adds write support to meson efuse driver.
> The first patch just changes the way the nvmem data are allocated w/o
> any functional changes. The second patches actually adds write support.
> 
> The memory being an OTP, it is safer if it remains read-only by default,
> which is why I also submitted this DT patch [0].
> 
> If a user knows what he is doing, it should be easy to remove the
> read-only property from the board DT. This can be done in u-boot, before
> starting linux:
> 
>  > fdt rm /efuse read-only
> 
> Tested on the gxl libretech-cc

Hi Srinivas,

Is this patchset ok with you ? Do you want to me to change something ?

Regards
Jerome

> 
> [0]: https://lkml.kernel.org/r/20180316145021.8517-1-jbrunet@baylibre.com
> 
> Jerome Brunet (2):
>   nvmem: meson-efuse: remove econfig global
>   nvmem: meson-efuse: add write support
> 
>  drivers/nvmem/meson-efuse.c | 37 +++++++++++++++++++++++++++----------
>  1 file changed, 27 insertions(+), 10 deletions(-)
> 

Re: [PATCH 0/2] nvmem: meson-efuse: add write support

[Srinivas Kandagatla]

On 19/04/18 15:13, Jerome Brunet wrote:
> On Fri, 2018-03-16 at 16:01 +0100, Jerome Brunet wrote:
>> This changeset adds write support to meson efuse driver.
>> The first patch just changes the way the nvmem data are allocated w/o
>> any functional changes. The second patches actually adds write support.
>>
>> The memory being an OTP, it is safer if it remains read-only by default,
>> which is why I also submitted this DT patch [0].
>>
>> If a user knows what he is doing, it should be easy to remove the
>> read-only property from the board DT. This can be done in u-boot, before
>> starting linux:
>>
>>   > fdt rm /efuse read-only
>>
>> Tested on the gxl libretech-cc
> 
> Hi Srinivas,
> 
> Is this patchset ok with you ? Do you want to me to change something ?
> 
Patches look good to me, Can you rebase them on top of 4.17, I will send 
it to Greg once rc4 is out.

thanks,
srini
> Regards
> Jerome
> 
>>
>> [0]: https://lkml.kernel.org/r/20180316145021.8517-1-jbrunet@baylibre.com
>>
>> Jerome Brunet (2):
>>    nvmem: meson-efuse: remove econfig global
>>    nvmem: meson-efuse: add write support
>>
>>   drivers/nvmem/meson-efuse.c | 37 +++++++++++++++++++++++++++----------
>>   1 file changed, 27 insertions(+), 10 deletions(-)
>>
> 

Re: [PATCH 0/2] nvmem: meson-efuse: add write support

[Kevin Hilman]

Jerome Brunet <jbrunet@baylibre.com> writes:

> This changeset adds write support to meson efuse driver.
> The first patch just changes the way the nvmem data are allocated w/o
> any functional changes. The second patches actually adds write support.
>
> The memory being an OTP, it is safer if it remains read-only by default,
> which is why I also submitted this DT patch [0].
>
> If a user knows what he is doing, it should be easy to remove the
> read-only property from the board DT. This can be done in u-boot, before
> starting linux:
>
>  > fdt rm /efuse read-only
>
> Tested on the gxl libretech-cc

For the series,

Reviewed-by: Kevin Hilman <khilman@baylibre.com>