[PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Björn Ardö]

If the slave eeprom has a "firmware-name" in devicetree, then
pre-load the data in the eeprom with this file. Otherwise we
init the eeprom with 0xFF.

Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
---
 drivers/i2c/i2c-slave-eeprom.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
index cb415b10642f..c846c96c25c9 100644
--- a/drivers/i2c/i2c-slave-eeprom.c
+++ b/drivers/i2c/i2c-slave-eeprom.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/firmware.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -120,6 +121,26 @@ static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kob
 	return count;
 }
 
+static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,
+					 unsigned int size)
+{
+	const struct firmware *fw;
+	const char *eeprom_data;
+	int error = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);
+
+	if (!error) {
+		int ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
+						    eeprom->buffer, size);
+		if (ret)
+			return ret;
+		release_firmware(fw);
+	} else {
+		/* An empty eeprom typically has all bits set to 1 */
+		memset(eeprom->buffer, 0xFF, size);
+	}
+	return 0;
+}
+
 static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct eeprom_data *eeprom;
@@ -138,6 +159,10 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
 	spin_lock_init(&eeprom->buffer_lock);
 	i2c_set_clientdata(client, eeprom);
 
+	ret = i2c_slave_init_eeprom_data(eeprom, client, size);
+	if (ret)
+		return ret;
+
 	sysfs_bin_attr_init(&eeprom->bin);
 	eeprom->bin.attr.name = "slave-eeprom";
 	eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;
-- 
2.11.0

Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Wolfram Sang]

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On Fri, Apr 24, 2020 at 11:04:43AM +0200, Björn Ardö wrote:
> If the slave eeprom has a "firmware-name" in devicetree, then
> pre-load the data in the eeprom with this file. Otherwise we
> init the eeprom with 0xFF.
> 
> Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>

I like it a lot, thanks! Maybe we could add a SoB from Patrick for his
0xff-suggestion (but keeping you as the patch author).

Is this okay for everyone?

> ---
>  drivers/i2c/i2c-slave-eeprom.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
> index cb415b10642f..c846c96c25c9 100644
> --- a/drivers/i2c/i2c-slave-eeprom.c
> +++ b/drivers/i2c/i2c-slave-eeprom.c
> @@ -18,6 +18,7 @@
>   */
>  
>  #include <linux/bitfield.h>
> +#include <linux/firmware.h>
>  #include <linux/i2c.h>
>  #include <linux/init.h>
>  #include <linux/module.h>
> @@ -120,6 +121,26 @@ static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kob
>  	return count;
>  }
>  
> +static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,
> +					 unsigned int size)
> +{
> +	const struct firmware *fw;
> +	const char *eeprom_data;
> +	int error = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);
> +
> +	if (!error) {
> +		int ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
> +						    eeprom->buffer, size);
> +		if (ret)
> +			return ret;
> +		release_firmware(fw);
> +	} else {
> +		/* An empty eeprom typically has all bits set to 1 */
> +		memset(eeprom->buffer, 0xFF, size);
> +	}
> +	return 0;
> +}
> +
>  static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  {
>  	struct eeprom_data *eeprom;
> @@ -138,6 +159,10 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
>  	spin_lock_init(&eeprom->buffer_lock);
>  	i2c_set_clientdata(client, eeprom);
>  
> +	ret = i2c_slave_init_eeprom_data(eeprom, client, size);
> +	if (ret)
> +		return ret;
> +
>  	sysfs_bin_attr_init(&eeprom->bin);
>  	eeprom->bin.attr.name = "slave-eeprom";
>  	eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;
> -- 
> 2.11.0
> 

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Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Bjorn Ardo]

On 4/24/20 12:03 PM, Wolfram Sang wrote:
> On Fri, Apr 24, 2020 at 11:04:43AM +0200, Björn Ardö wrote:
>> If the slave eeprom has a "firmware-name" in devicetree, then
>> pre-load the data in the eeprom with this file. Otherwise we
>> init the eeprom with 0xFF.
>>
>> Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
> I like it a lot, thanks! Maybe we could add a SoB from Patrick for his
> 0xff-suggestion (but keeping you as the patch author).
>
> Is this okay for everyone?


OK for me!

Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Patrick Williams]

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On Fri, Apr 24, 2020 at 12:06:44PM +0200, Bjorn Ardo wrote:
> 
> On 4/24/20 12:03 PM, Wolfram Sang wrote:
> > On Fri, Apr 24, 2020 at 11:04:43AM +0200, Björn Ardö wrote:
> >> If the slave eeprom has a "firmware-name" in devicetree, then
> >> pre-load the data in the eeprom with this file. Otherwise we
> >> init the eeprom with 0xFF.
> >>
> >> Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
> > I like it a lot, thanks! Maybe we could add a SoB from Patrick for his
> > 0xff-suggestion (but keeping you as the patch author).
> >
> > Is this okay for everyone?
> 
> 
> OK for me!
> 

Fine by me, also.

-- 
Patrick Williams

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Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Wolfram Sang]

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On second look, two questions:

> +	if (!error) {
> +		int ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
> +						    eeprom->buffer, size);
> +		if (ret)
> +			return ret;

Aren't we leaking 'fw' here?

Also, do we need 'error' and 'ret'? Can't we reuse one of them?

> +		release_firmware(fw);


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Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Bjorn Ardo]

On 4/24/20 1:13 PM, Wolfram Sang wrote:

> On second look, two questions:
>
>> +	if (!error) {
>> +		int ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
>> +						    eeprom->buffer, size);
>> +		if (ret)
>> +			return ret;
> Aren't we leaking 'fw' here?


As I can see in drivers/base/firmware_loader/main.c in function 
_request_firmware, then the fw will be released internally if it returns 
an error value.


> Also, do we need 'error' and 'ret'? Can't we reuse one of them?


Yes, I can fix that.


/BA

Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Wolfram Sang]

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> As I can see in drivers/base/firmware_loader/main.c in function
> _request_firmware, then the fw will be released internally if it returns an
> error value.

Ouch, of course!

> > Also, do we need 'error' and 'ret'? Can't we reuse one of them?
> 
> Yes, I can fix that.

Great, thanks!


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Re: [PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Bjorn Ardo]

You got a new patch (ignor the first one, I forgot to update the version 
number).

On 4/24/20 1:27 PM, Wolfram Sang wrote:
>> As I can see in drivers/base/firmware_loader/main.c in function
>> _request_firmware, then the fw will be released internally if it returns an
>> error value.
> Ouch, of course!
>
>>> Also, do we need 'error' and 'ret'? Can't we reuse one of them?
>> Yes, I can fix that.
> Great, thanks!
>

[PATCHv2] i2c: slave-eeprom: Make it possible to pre-load eeprom data

[Björn Ardö]

If the slave eeprom has a "firmware-name" in devicetree, then
pre-load the data in the eeprom with this file. Otherwise we
init the eeprom with 0xFF.

Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
---
 drivers/i2c/i2c-slave-eeprom.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
index cb415b10642f..b425cefea92c 100644
--- a/drivers/i2c/i2c-slave-eeprom.c
+++ b/drivers/i2c/i2c-slave-eeprom.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/firmware.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -120,6 +121,26 @@ static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kob
 	return count;
 }
 
+static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,
+					 unsigned int size)
+{
+	const struct firmware *fw;
+	const char *eeprom_data;
+	int error = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);
+
+	if (!error) {
+		error = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
+						  eeprom->buffer, size);
+		if (error)
+			return error;
+		release_firmware(fw);
+	} else {
+		/* An empty eeprom typically has all bits set to 1 */
+		memset(eeprom->buffer, 0xFF, size);
+	}
+	return 0;
+}
+
 static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct eeprom_data *eeprom;
@@ -138,6 +159,10 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
 	spin_lock_init(&eeprom->buffer_lock);
 	i2c_set_clientdata(client, eeprom);
 
+	ret = i2c_slave_init_eeprom_data(eeprom, client, size);
+	if (ret)
+		return ret;
+
 	sysfs_bin_attr_init(&eeprom->bin);
 	eeprom->bin.attr.name = "slave-eeprom";
 	eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;
-- 
2.11.0