[PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Christian Gmeiner]

I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
bus driver. This bus driver does not support
I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
to be able to write the eeprom. This patch adds support for
I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
It is quite slow, but it works.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
---
 drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2baeec5..723b411 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -56,6 +56,7 @@ struct at24_data {
 	struct at24_platform_data chip;
 	struct memory_accessor macc;
 	int use_smbus;
+	int use_smbuse_write;
 
 	/*
 	 * Lock protects against activities from other Linux tasks,
@@ -324,7 +325,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
 {
 	struct i2c_client *client;
 	struct i2c_msg msg;
-	ssize_t status;
+	ssize_t status = 0;
 	unsigned long timeout, write_time;
 	unsigned next_page;
 
@@ -365,9 +366,18 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
 	timeout = jiffies + msecs_to_jiffies(write_timeout);
 	do {
 		write_time = jiffies;
-		if (at24->use_smbus) {
-			status = i2c_smbus_write_i2c_block_data(client,
-					offset, count, buf);
+		if (at24->use_smbuse_write) {
+			switch (at24->use_smbuse_write) {
+			case I2C_SMBUS_I2C_BLOCK_DATA:
+				status = i2c_smbus_write_i2c_block_data(client,
+						offset, count, buf);
+				break;
+			case I2C_SMBUS_BYTE_DATA:
+				status = i2c_smbus_write_byte_data(client,
+						offset, buf[0]);
+				break;
+			}
+
 			if (status == 0)
 				status = count;
 		} else {
@@ -484,6 +494,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	struct at24_platform_data chip;
 	bool writable;
 	int use_smbus = 0;
+	int use_smbus_write = 0;
 	struct at24_data *at24;
 	int err;
 	unsigned i, num_addresses;
@@ -547,6 +558,18 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		}
 	}
 
+	/* Use I2C operations unless we're stuck with SMBus extensions. */
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		if (!i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
+			use_smbus_write = I2C_SMBUS_I2C_BLOCK_DATA;
+		} else if (i2c_check_functionality(client->adapter,
+				I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+			use_smbus_write = I2C_SMBUS_BYTE_DATA;
+			chip.page_size = 1;
+		}
+	}
+
 	if (chip.flags & AT24_FLAG_TAKE8ADDR)
 		num_addresses = 8;
 	else
@@ -562,6 +585,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	mutex_init(&at24->lock);
 	at24->use_smbus = use_smbus;
+	at24->use_smbuse_write = use_smbus_write;
 	at24->chip = chip;
 	at24->num_addresses = num_addresses;
 
@@ -579,8 +603,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	writable = !(chip.flags & AT24_FLAG_READONLY);
 	if (writable) {
-		if (!use_smbus || i2c_check_functionality(client->adapter,
-				I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
+		if (!use_smbus || use_smbus_write) {
 
 			unsigned write_max = chip.page_size;
 
-- 
1.7.12.2.421.g261b511

Re: [PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Christian Gmeiner]

ping
--
Christian Gmeiner, MSc


2012/12/19 Christian Gmeiner <christian.gmeiner@gmail.com>:
> I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
> bus driver. This bus driver does not support
> I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
> to be able to write the eeprom. This patch adds support for
> I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
> It is quite slow, but it works.
>
> Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
> ---
>  drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------
>  1 file changed, 29 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 2baeec5..723b411 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -56,6 +56,7 @@ struct at24_data {
>         struct at24_platform_data chip;
>         struct memory_accessor macc;
>         int use_smbus;
> +       int use_smbuse_write;
>
>         /*
>          * Lock protects against activities from other Linux tasks,
> @@ -324,7 +325,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
>  {
>         struct i2c_client *client;
>         struct i2c_msg msg;
> -       ssize_t status;
> +       ssize_t status = 0;
>         unsigned long timeout, write_time;
>         unsigned next_page;
>
> @@ -365,9 +366,18 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf,
>         timeout = jiffies + msecs_to_jiffies(write_timeout);
>         do {
>                 write_time = jiffies;
> -               if (at24->use_smbus) {
> -                       status = i2c_smbus_write_i2c_block_data(client,
> -                                       offset, count, buf);
> +               if (at24->use_smbuse_write) {
> +                       switch (at24->use_smbuse_write) {
> +                       case I2C_SMBUS_I2C_BLOCK_DATA:
> +                               status = i2c_smbus_write_i2c_block_data(client,
> +                                               offset, count, buf);
> +                               break;
> +                       case I2C_SMBUS_BYTE_DATA:
> +                               status = i2c_smbus_write_byte_data(client,
> +                                               offset, buf[0]);
> +                               break;
> +                       }
> +
>                         if (status == 0)
>                                 status = count;
>                 } else {
> @@ -484,6 +494,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>         struct at24_platform_data chip;
>         bool writable;
>         int use_smbus = 0;
> +       int use_smbus_write = 0;
>         struct at24_data *at24;
>         int err;
>         unsigned i, num_addresses;
> @@ -547,6 +558,18 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>                 }
>         }
>
> +       /* Use I2C operations unless we're stuck with SMBus extensions. */
> +       if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> +               if (!i2c_check_functionality(client->adapter,
> +                               I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
> +                       use_smbus_write = I2C_SMBUS_I2C_BLOCK_DATA;
> +               } else if (i2c_check_functionality(client->adapter,
> +                               I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
> +                       use_smbus_write = I2C_SMBUS_BYTE_DATA;
> +                       chip.page_size = 1;
> +               }
> +       }
> +
>         if (chip.flags & AT24_FLAG_TAKE8ADDR)
>                 num_addresses = 8;
>         else
> @@ -562,6 +585,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>
>         mutex_init(&at24->lock);
>         at24->use_smbus = use_smbus;
> +       at24->use_smbuse_write = use_smbus_write;
>         at24->chip = chip;
>         at24->num_addresses = num_addresses;
>
> @@ -579,8 +603,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>
>         writable = !(chip.flags & AT24_FLAG_READONLY);
>         if (writable) {
> -               if (!use_smbus || i2c_check_functionality(client->adapter,
> -                               I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
> +               if (!use_smbus || use_smbus_write) {
>
>                         unsigned write_max = chip.page_size;
>
> --
> 1.7.12.2.421.g261b511
>

Re: [PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1236 bytes --]

On Wed, Dec 19, 2012 at 05:07:09PM +0100, Christian Gmeiner wrote:
> I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
> bus driver. This bus driver does not support
> I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
> to be able to write the eeprom. This patch adds support for
> I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
> It is quite slow, but it works.
> 
> Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
> ---
>  drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------
>  1 file changed, 29 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 2baeec5..723b411 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -56,6 +56,7 @@ struct at24_data {
>  	struct at24_platform_data chip;
>  	struct memory_accessor macc;
>  	int use_smbus;
> +	int use_smbuse_write;

Can't you use the same 'use_smbus' variable and do a similar switch-case
as in the read function?

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

[-- Attachment #2: Digital signature --]
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Re: [PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Christian Gmeiner]

2013/1/24 Wolfram Sang <w.sang@pengutronix.de>:
> On Wed, Dec 19, 2012 at 05:07:09PM +0100, Christian Gmeiner wrote:
>> I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
>> bus driver. This bus driver does not support
>> I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
>> to be able to write the eeprom. This patch adds support for
>> I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
>> It is quite slow, but it works.
>>
>> Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
>> ---
>>  drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------
>>  1 file changed, 29 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index 2baeec5..723b411 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -56,6 +56,7 @@ struct at24_data {
>>       struct at24_platform_data chip;
>>       struct memory_accessor macc;
>>       int use_smbus;
>> +     int use_smbuse_write;
>
> Can't you use the same 'use_smbus' variable and do a similar switch-case
> as in the read function?
>

Sorry for the really late answer.

I am not sure if there exits some i2c buses which have different
access methods for read and write.
E.g. I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and I2C_FUNC_SMBUS_READ_BYTE_DATA

If there will never be such a combination then I can reuse the same
'use_smbus' variable.

--
Christian Gmeiner, MSc

Re: [PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Christian Gmeiner]

Using the new mail address of wolfram sang - got the following error:


Delivery to the following recipient failed permanently:

     w.sang@pengutronix.de

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the
server for the recipient domainpengutronix.de by mail.pengutronix.de.
[2001:6f8:1178:4:290:27ff:fe1d:cc33].

The error that the other server returned was:
550 Account closed - please contact info@pengutronix.de instead


2013/3/27 Christian Gmeiner <christian.gmeiner@gmail.com>:
> 2013/1/24 Wolfram Sang <w.sang@pengutronix.de>:
>> On Wed, Dec 19, 2012 at 05:07:09PM +0100, Christian Gmeiner wrote:
>>> I have a at24 EEPROM connected via i2c bus provided by ISCH i2c
>>> bus driver. This bus driver does not support
>>> I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way
>>> to be able to write the eeprom. This patch adds support for
>>> I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data.
>>> It is quite slow, but it works.
>>>
>>> Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
>>> ---
>>>  drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------
>>>  1 file changed, 29 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>>> index 2baeec5..723b411 100644
>>> --- a/drivers/misc/eeprom/at24.c
>>> +++ b/drivers/misc/eeprom/at24.c
>>> @@ -56,6 +56,7 @@ struct at24_data {
>>>       struct at24_platform_data chip;
>>>       struct memory_accessor macc;
>>>       int use_smbus;
>>> +     int use_smbuse_write;
>>
>> Can't you use the same 'use_smbus' variable and do a similar switch-case
>> as in the read function?
>>
>
> Sorry for the really late answer.
>
> I am not sure if there exits some i2c buses which have different
> access methods for read and write.
> E.g. I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and I2C_FUNC_SMBUS_READ_BYTE_DATA
>
> If there will never be such a combination then I can reuse the same
> 'use_smbus' variable.
>

--
Christian Gmeiner, MSc

Re: [PATCH] at24: extend driver to allow writing via i2c_smbus_write_byte_data

[Robert Schwebel]

Hi Christian,

On Mon, Apr 08, 2013 at 08:56:03AM +0200, Christian Gmeiner wrote:
> Using the new mail address of wolfram sang - got the following error:
> 
> 
> Delivery to the following recipient failed permanently:
> 
>      w.sang@pengutronix.de
> 
> Technical details of permanent failure:
> Google tried to deliver your message, but it was rejected by the
> server for the recipient domainpengutronix.de by mail.pengutronix.de.
> [2001:6f8:1178:4:290:27ff:fe1d:cc33].
> 
> The error that the other server returned was:
> 550 Account closed - please contact info@pengutronix.de instead

Using wsa@the-dreams.de is correct. Mainline is already up to date.

rsc <- info@pengutronix.de
-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |