[PATCH V2 0/3] at24: parse OF-data

[PATCH V2 0/3] at24: parse OF-data

[Wolfram Sang]

Here is the second round of this series:

* 1/3 now uses __be32 instead of u32.
* 2/3 is new and adds some more sanity checks
* 3/3 is unchanged

Grant, I hope you can pick 2/3 as well. Should make things easier and it is
just a misc-driver (which I maintain) :)

Wolfram Sang (3):
  misc: at24: parse OF-data, too
  misc: at24: add more sanity checks for parameters
  powerpc: pcm030/032: add pagesize to dts

 Documentation/powerpc/dts-bindings/eeprom.txt |   28 ++++++++++++++++
 arch/powerpc/boot/dts/pcm030.dts              |    1 +
 arch/powerpc/boot/dts/pcm032.dts              |    3 +-
 drivers/misc/eeprom/at24.c                    |   43 +++++++++++++++++++++---
 4 files changed, 68 insertions(+), 7 deletions(-)
 create mode 100644 Documentation/powerpc/dts-bindings/eeprom.txt

-- 
1.7.2.3

[PATCH 1/3] misc: at24: parse OF-data, too

[Wolfram Sang]

Information about the pagesize and read-only-status may also come from
the devicetree. Parse this data, too, and act accordingly. While we are
here, change the initialization printout a bit. write_max is useful to
know to detect performance bottlenecks, the rest is superfluous.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
---

Changes since last version:

- use __be32 instead of u32

 Documentation/powerpc/dts-bindings/eeprom.txt |   28 +++++++++++++++++++++
 drivers/misc/eeprom/at24.c                    |   33 ++++++++++++++++++++----
 2 files changed, 55 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/powerpc/dts-bindings/eeprom.txt

diff --git a/Documentation/powerpc/dts-bindings/eeprom.txt b/Documentation/powerpc/dts-bindings/eeprom.txt
new file mode 100644
index 0000000..4342c10
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/eeprom.txt
@@ -0,0 +1,28 @@
+EEPROMs (I2C)
+
+Required properties:
+
+  - compatible : should be "<manufacturer>,<type>"
+		 If there is no specific driver for <manufacturer>, a generic
+		 driver based on <type> is selected. Possible types are:
+		 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
+		 24c128, 24c256, 24c512, 24c1024, spd
+
+  - reg : the I2C address of the EEPROM
+
+Optional properties:
+
+  - pagesize : the length of the pagesize for writing. Please consult the
+               manual of your device, that value varies a lot. A wrong value
+	       may result in data loss! If not specified, a safety value of
+	       '1' is used which will be very slow.
+
+  - read-only: this parameterless property disables writes to the eeprom
+
+Example:
+
+eeprom@52 {
+	compatible = "atmel,24c32";
+	reg = <0x52>;
+	pagesize = <32>;
+};
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 559b0b3..3a53efc 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -20,6 +20,7 @@
 #include <linux/log2.h>
 #include <linux/bitops.h>
 #include <linux/jiffies.h>
+#include <linux/of.h>
 #include <linux/i2c.h>
 #include <linux/i2c/at24.h>
 
@@ -457,6 +458,27 @@ static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
 
 /*-------------------------------------------------------------------------*/
 
+#ifdef CONFIG_OF
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{
+	const __be32 *val;
+	struct device_node *node = client->dev.of_node;
+
+	if (node) {
+		if (of_get_property(node, "read-only", NULL))
+			chip->flags |= AT24_FLAG_READONLY;
+		val = of_get_property(node, "pagesize", NULL);
+		if (val)
+			chip->page_size = be32_to_cpup(val);
+	}
+}
+#else
+static void at24_get_ofdata(struct i2c_client *client,
+		struct at24_platform_data *chip)
+{ }
+#endif /* CONFIG_OF */
+
 static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct at24_platform_data chip;
@@ -485,6 +507,9 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		 */
 		chip.page_size = 1;
 
+		/* update chipdata if OF is present */
+		at24_get_ofdata(client, &chip);
+
 		chip.setup = NULL;
 		chip.context = NULL;
 	}
@@ -597,19 +622,15 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 
 	i2c_set_clientdata(client, at24);
 
-	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
+	dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
 		at24->bin.size, client->name,
-		writable ? "(writable)" : "(read-only)");
+		writable ? "writable" : "read-only", at24->write_max);
 	if (use_smbus == I2C_SMBUS_WORD_DATA ||
 	    use_smbus == I2C_SMBUS_BYTE_DATA) {
 		dev_notice(&client->dev, "Falling back to %s reads, "
 			   "performance will suffer\n", use_smbus ==
 			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
 	}
-	dev_dbg(&client->dev,
-		"page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
-		chip.page_size, num_addresses,
-		at24->write_max, use_smbus);
 
 	/* export data to kernel code */
 	if (chip.setup)
-- 
1.7.2.3

[PATCH 2/3] misc: at24: add more sanity checks for parameters

[Wolfram Sang]

Side-effects happen when passing 0 to either io_limit or page_size. Give
an error in case of this misconfiguration.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
---
 drivers/misc/eeprom/at24.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 3a53efc..ab1ad41 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -517,6 +517,11 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (!is_power_of_2(chip.byte_len))
 		dev_warn(&client->dev,
 			"byte_len looks suspicious (no power of 2)!\n");
+	if (!chip.page_size) {
+		dev_err(&client->dev, "page_size must not be 0!\n");
+		err = -EINVAL;
+		goto err_out;
+	}
 	if (!is_power_of_2(chip.page_size))
 		dev_warn(&client->dev,
 			"page_size looks suspicious (no power of 2)!\n");
@@ -681,6 +686,11 @@ static struct i2c_driver at24_driver = {
 
 static int __init at24_init(void)
 {
+	if (!io_limit) {
+		pr_err("at24: io_limit must not be 0!\n");
+		return -EINVAL;
+	}
+
 	io_limit = rounddown_pow_of_two(io_limit);
 	return i2c_add_driver(&at24_driver);
 }
-- 
1.7.2.3

[PATCH 3/3] powerpc: pcm030/032: add pagesize to dts

[Wolfram Sang]

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
---
 arch/powerpc/boot/dts/pcm030.dts |    1 +
 arch/powerpc/boot/dts/pcm032.dts |    3 ++-
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/boot/dts/pcm030.dts b/arch/powerpc/boot/dts/pcm030.dts
index 8a4ec30..e7c36bc 100644
--- a/arch/powerpc/boot/dts/pcm030.dts
+++ b/arch/powerpc/boot/dts/pcm030.dts
@@ -259,6 +259,7 @@
 			eeprom@52 {
 				compatible = "catalyst,24c32";
 				reg = <0x52>;
+				pagesize = <32>;
 			};
 		};
 
diff --git a/arch/powerpc/boot/dts/pcm032.dts b/arch/powerpc/boot/dts/pcm032.dts
index 85d857a..e175e2c 100644
--- a/arch/powerpc/boot/dts/pcm032.dts
+++ b/arch/powerpc/boot/dts/pcm032.dts
@@ -257,8 +257,9 @@
 				reg = <0x51>;
 			};
 			eeprom@52 {
-				compatible = "at24,24c32";
+				compatible = "catalyst,24c32";
 				reg = <0x52>;
+				pagesize = <32>;
 			};
 		};
 
-- 
1.7.2.3

Re: [PATCH 1/3] misc: at24: parse OF-data, too

[Stijn Devriendt]

Hi Wolfram,

I'm surprised that this would work. I've patched the at24 driver as well
to use OF data, but took a different approach.

As far as I could tell, using compatible = <24c64>; didn't load the right 
module
(module name is at24) and using at24 caused a device id mismatch because
at24 is not a known device ID. I could be wrong here and if so, I'd very 
much
like a source code hint as to why...

My patch worked by changing drivers/of/of_i2c.c to allow a generic
kind = " " statement that was filled in as i2c_board_info.type, to allow
the module name and the device id to be different.
This makes the at24 driver no longer rely on probing (which it claims
is buggy anyway) and also benefits other drivers that support multiple
devices, but where probing is difficult (e.g. lm90 driver).

I'm in the process of getting employer approval to get these patches 
upstream.

Regards,
Stijn

-----Oorspronkelijk bericht----- 
From: Wolfram Sang
Sent: Wednesday, November 17, 2010 1:00 PM
To: devicetree-discuss@ozlabs.org
Cc: linuxppc-dev@ozlabs.org
Subject: [PATCH 1/3] misc: at24: parse OF-data, too

Information about the pagesize and read-only-status may also come from
the devicetree. Parse this data, too, and act accordingly. While we are
here, change the initialization printout a bit. write_max is useful to
know to detect performance bottlenecks, the rest is superfluous.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
---

Changes since last version:

- use __be32 instead of u32

Documentation/powerpc/dts-bindings/eeprom.txt |   28 +++++++++++++++++++++
drivers/misc/eeprom/at24.c                    |   33 
++++++++++++++++++++----
2 files changed, 55 insertions(+), 6 deletions(-)
create mode 100644 Documentation/powerpc/dts-bindings/eeprom.txt

diff --git a/Documentation/powerpc/dts-bindings/eeprom.txt 
b/Documentation/powerpc/dts-bindings/eeprom.txt
new file mode 100644
index 0000000..4342c10
--- /dev/null
+++ b/Documentation/powerpc/dts-bindings/eeprom.txt
@@ -0,0 +1,28 @@
+EEPROMs (I2C)
+
+Required properties:
+
+  - compatible : should be "<manufacturer>,<type>"
+ If there is no specific driver for <manufacturer>, a generic
+ driver based on <type> is selected. Possible types are:
+ 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
+ 24c128, 24c256, 24c512, 24c1024, spd
+
+  - reg : the I2C address of the EEPROM
+
+Optional properties:
+
+  - pagesize : the length of the pagesize for writing. Please consult the
+               manual of your device, that value varies a lot. A wrong 
value
+        may result in data loss! If not specified, a safety value of
+        '1' is used which will be very slow.
+
+  - read-only: this parameterless property disables writes to the eeprom
+
+Example:
+
+eeprom@52 {
+ compatible = "atmel,24c32";
+ reg = <0x52>;
+ pagesize = <32>;
+};
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 559b0b3..3a53efc 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -20,6 +20,7 @@
#include <linux/log2.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>
+#include <linux/of.h>
#include <linux/i2c.h>
#include <linux/i2c/at24.h>

@@ -457,6 +458,27 @@ static ssize_t at24_macc_write(struct memory_accessor 
*macc, const char *buf,

/*-------------------------------------------------------------------------*/

+#ifdef CONFIG_OF
+static void at24_get_ofdata(struct i2c_client *client,
+ struct at24_platform_data *chip)
+{
+ const __be32 *val;
+ struct device_node *node = client->dev.of_node;
+
+ if (node) {
+ if (of_get_property(node, "read-only", NULL))
+ chip->flags |= AT24_FLAG_READONLY;
+ val = of_get_property(node, "pagesize", NULL);
+ if (val)
+ chip->page_size = be32_to_cpup(val);
+ }
+}
+#else
+static void at24_get_ofdata(struct i2c_client *client,
+ struct at24_platform_data *chip)
+{ }
+#endif /* CONFIG_OF */
+
static int at24_probe(struct i2c_client *client, const struct i2c_device_id 
*id)
{
  struct at24_platform_data chip;
@@ -485,6 +507,9 @@ static int at24_probe(struct i2c_client *client, const 
struct i2c_device_id *id)
  */
  chip.page_size = 1;

+ /* update chipdata if OF is present */
+ at24_get_ofdata(client, &chip);
+
  chip.setup = NULL;
  chip.context = NULL;
  }
@@ -597,19 +622,15 @@ static int at24_probe(struct i2c_client *client, const 
struct i2c_device_id *id)

  i2c_set_clientdata(client, at24);

- dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
+ dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
  at24->bin.size, client->name,
- writable ? "(writable)" : "(read-only)");
+ writable ? "writable" : "read-only", at24->write_max);
  if (use_smbus == I2C_SMBUS_WORD_DATA ||
      use_smbus == I2C_SMBUS_BYTE_DATA) {
  dev_notice(&client->dev, "Falling back to %s reads, "
     "performance will suffer\n", use_smbus ==
     I2C_SMBUS_WORD_DATA ? "word" : "byte");
  }
- dev_dbg(&client->dev,
- "page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
- chip.page_size, num_addresses,
- at24->write_max, use_smbus);

  /* export data to kernel code */
  if (chip.setup)
-- 
1.7.2.3

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Linuxppc-dev@lists.ozlabs.org
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Re: [PATCH 1/3] misc: at24: parse OF-data, too

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1288 bytes --]

Hi,

> As far as I could tell, using compatible = <24c64>; didn't load the right
> module (module name is at24) and using at24 caused a device id mismatch
> because at24 is not a known device ID. I could be wrong here and if so, I'd
> very  much like a source code hint as to why...

Have you tried "<vendor>, 24c64"? All I can say is that it works for me. Plain
at24 worked for years with pcm030.dts and pcm032.dts, so I don't know which
issue you are facing. This patch is just about extending the support.

> My patch worked by changing drivers/of/of_i2c.c to allow a generic
> kind = " " statement that was filled in as i2c_board_info.type, to allow
> the module name and the device id to be different.
> This makes the at24 driver no longer rely on probing (which it claims
> is buggy anyway) and also benefits other drivers that support multiple
> devices, but where probing is difficult (e.g. lm90 driver).
>
> I'm in the process of getting employer approval to get these patches  
> upstream.

I hope you will get it approved, it is a lot easier to talk about code :)

Best regards,

   Wolfram

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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 197 bytes --]

Re: [PATCH 1/3] misc: at24: parse OF-data, too

[Stijn Devriendt]

On Sat, Nov 20, 2010 at 1:42 PM, Wolfram Sang <w.sang@pengutronix.de> wrote=
:
> Hi,
>
>> As far as I could tell, using compatible =3D <24c64>; didn't load the ri=
ght
>> module (module name is at24) and using at24 caused a device id mismatch
>> because at24 is not a known device ID. I could be wrong here and if so, =
I'd
>> very =A0much like a source code hint as to why...
>
> Have you tried "<vendor>, 24c64"? All I can say is that it works for me. =
Plain
> at24 worked for years with pcm030.dts and pcm032.dts, so I don't know whi=
ch
> issue you are facing. This patch is just about extending the support.

According to of_modalias_node, the prefix is stripped anyway, so that
wouldn't help.
The code probably worked using the buggy probing...
>
>> My patch worked by changing drivers/of/of_i2c.c to allow a generic
>> kind =3D " " statement that was filled in as i2c_board_info.type, to all=
ow
>> the module name and the device id to be different.
>> This makes the at24 driver no longer rely on probing (which it claims
>> is buggy anyway) and also benefits other drivers that support multiple
>> devices, but where probing is difficult (e.g. lm90 driver).
>>
>> I'm in the process of getting employer approval to get these patches
>> upstream.
>

It'll get approved ;) It's the first time I'm taking these steps, but
the procedures
are there, so at most it'll take some extra time.

> I hope you will get it approved, it is a lot easier to talk about code :)
>
> Best regards,
>
> =A0 Wolfram
>
> --
> Pengutronix e.K. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | Wo=
lfram Sang =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|
> Industrial Linux Solutions =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | http://www.p=
engutronix.de/ =A0|
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.9 (GNU/Linux)
>
> iEYEARECAAYFAkznwjIACgkQD27XaX1/VRssnwCgg55UCwZFLcMI8kJI3mhCJQxL
> N7kAoJHpLn5BJpNjET+ngaQFrGxUBQm1
> =3DtyTb
> -----END PGP SIGNATURE-----
>
>

Re: [PATCH 1/3] misc: at24: parse OF-data, too

[Stijn Devriendt]

Hi Wolfram,

I seem to be mistaken. I retried "compatible=3D<linux,24c64>" and it did
all the right
things. I was mistaken that request_module() only takes the driver
name, at24 in this
case, and not all device names in the table_ids.

This pretty much makes my patch redundant. Thanks for helping me clear
things out.

Regards,
Stijn

On Sat, Nov 20, 2010 at 1:42 PM, Wolfram Sang <w.sang@pengutronix.de> wrote=
:
> Hi,
>
>> As far as I could tell, using compatible =3D <24c64>; didn't load the ri=
ght
>> module (module name is at24) and using at24 caused a device id mismatch
>> because at24 is not a known device ID. I could be wrong here and if so, =
I'd
>> very =A0much like a source code hint as to why...
>
> Have you tried "<vendor>, 24c64"? All I can say is that it works for me. =
Plain
> at24 worked for years with pcm030.dts and pcm032.dts, so I don't know whi=
ch
> issue you are facing. This patch is just about extending the support.
>
>> My patch worked by changing drivers/of/of_i2c.c to allow a generic
>> kind =3D " " statement that was filled in as i2c_board_info.type, to all=
ow
>> the module name and the device id to be different.
>> This makes the at24 driver no longer rely on probing (which it claims
>> is buggy anyway) and also benefits other drivers that support multiple
>> devices, but where probing is difficult (e.g. lm90 driver).
>>
>> I'm in the process of getting employer approval to get these patches
>> upstream.
>
> I hope you will get it approved, it is a lot easier to talk about code :)
>
> Best regards,
>
> =A0 Wolfram
>
> --
> Pengutronix e.K. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | Wo=
lfram Sang =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0|
> Industrial Linux Solutions =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | http://www.p=
engutronix.de/ =A0|
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.9 (GNU/Linux)
>
> iEYEARECAAYFAkznwjIACgkQD27XaX1/VRssnwCgg55UCwZFLcMI8kJI3mhCJQxL
> N7kAoJHpLn5BJpNjET+ngaQFrGxUBQm1
> =3DtyTb
> -----END PGP SIGNATURE-----
>
>

Re: [PATCH 2/3] misc: at24: add more sanity checks for parameters

[Grant Likely]

On Wed, Nov 17, 2010 at 01:00:49PM +0100, Wolfram Sang wrote:
> Side-effects happen when passing 0 to either io_limit or page_size. Give
> an error in case of this misconfiguration.
> 
> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
> ---

Applied for -next, thanks.

g.

>  drivers/misc/eeprom/at24.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 3a53efc..ab1ad41 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -517,6 +517,11 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  	if (!is_power_of_2(chip.byte_len))
>  		dev_warn(&client->dev,
>  			"byte_len looks suspicious (no power of 2)!\n");
> +	if (!chip.page_size) {
> +		dev_err(&client->dev, "page_size must not be 0!\n");
> +		err = -EINVAL;
> +		goto err_out;
> +	}
>  	if (!is_power_of_2(chip.page_size))
>  		dev_warn(&client->dev,
>  			"page_size looks suspicious (no power of 2)!\n");
> @@ -681,6 +686,11 @@ static struct i2c_driver at24_driver = {
>  
>  static int __init at24_init(void)
>  {
> +	if (!io_limit) {
> +		pr_err("at24: io_limit must not be 0!\n");
> +		return -EINVAL;
> +	}
> +
>  	io_limit = rounddown_pow_of_two(io_limit);
>  	return i2c_add_driver(&at24_driver);
>  }
> -- 
> 1.7.2.3
> 

Re: [PATCH 1/3] misc: at24: parse OF-data, too

[Grant Likely]

On Wed, Nov 17, 2010 at 01:00:48PM +0100, Wolfram Sang wrote:
> Information about the pagesize and read-only-status may also come from
> the devicetree. Parse this data, too, and act accordingly. While we are
> here, change the initialization printout a bit. write_max is useful to
> know to detect performance bottlenecks, the rest is superfluous.
> 
> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Applied for -next, thanks.

g.

> ---
> 
> Changes since last version:
> 
> - use __be32 instead of u32
> 
>  Documentation/powerpc/dts-bindings/eeprom.txt |   28 +++++++++++++++++++++
>  drivers/misc/eeprom/at24.c                    |   33 ++++++++++++++++++++----
>  2 files changed, 55 insertions(+), 6 deletions(-)
>  create mode 100644 Documentation/powerpc/dts-bindings/eeprom.txt
> 
> diff --git a/Documentation/powerpc/dts-bindings/eeprom.txt b/Documentation/powerpc/dts-bindings/eeprom.txt
> new file mode 100644
> index 0000000..4342c10
> --- /dev/null
> +++ b/Documentation/powerpc/dts-bindings/eeprom.txt
> @@ -0,0 +1,28 @@
> +EEPROMs (I2C)
> +
> +Required properties:
> +
> +  - compatible : should be "<manufacturer>,<type>"
> +		 If there is no specific driver for <manufacturer>, a generic
> +		 driver based on <type> is selected. Possible types are:
> +		 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
> +		 24c128, 24c256, 24c512, 24c1024, spd
> +
> +  - reg : the I2C address of the EEPROM
> +
> +Optional properties:
> +
> +  - pagesize : the length of the pagesize for writing. Please consult the
> +               manual of your device, that value varies a lot. A wrong value
> +	       may result in data loss! If not specified, a safety value of
> +	       '1' is used which will be very slow.
> +
> +  - read-only: this parameterless property disables writes to the eeprom
> +
> +Example:
> +
> +eeprom@52 {
> +	compatible = "atmel,24c32";
> +	reg = <0x52>;
> +	pagesize = <32>;
> +};
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 559b0b3..3a53efc 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -20,6 +20,7 @@
>  #include <linux/log2.h>
>  #include <linux/bitops.h>
>  #include <linux/jiffies.h>
> +#include <linux/of.h>
>  #include <linux/i2c.h>
>  #include <linux/i2c/at24.h>
>  
> @@ -457,6 +458,27 @@ static ssize_t at24_macc_write(struct memory_accessor *macc, const char *buf,
>  
>  /*-------------------------------------------------------------------------*/
>  
> +#ifdef CONFIG_OF
> +static void at24_get_ofdata(struct i2c_client *client,
> +		struct at24_platform_data *chip)
> +{
> +	const __be32 *val;
> +	struct device_node *node = client->dev.of_node;
> +
> +	if (node) {
> +		if (of_get_property(node, "read-only", NULL))
> +			chip->flags |= AT24_FLAG_READONLY;
> +		val = of_get_property(node, "pagesize", NULL);
> +		if (val)
> +			chip->page_size = be32_to_cpup(val);
> +	}
> +}
> +#else
> +static void at24_get_ofdata(struct i2c_client *client,
> +		struct at24_platform_data *chip)
> +{ }
> +#endif /* CONFIG_OF */
> +
>  static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  {
>  	struct at24_platform_data chip;
> @@ -485,6 +507,9 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  		 */
>  		chip.page_size = 1;
>  
> +		/* update chipdata if OF is present */
> +		at24_get_ofdata(client, &chip);
> +
>  		chip.setup = NULL;
>  		chip.context = NULL;
>  	}
> @@ -597,19 +622,15 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  
>  	i2c_set_clientdata(client, at24);
>  
> -	dev_info(&client->dev, "%zu byte %s EEPROM %s\n",
> +	dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n",
>  		at24->bin.size, client->name,
> -		writable ? "(writable)" : "(read-only)");
> +		writable ? "writable" : "read-only", at24->write_max);
>  	if (use_smbus == I2C_SMBUS_WORD_DATA ||
>  	    use_smbus == I2C_SMBUS_BYTE_DATA) {
>  		dev_notice(&client->dev, "Falling back to %s reads, "
>  			   "performance will suffer\n", use_smbus ==
>  			   I2C_SMBUS_WORD_DATA ? "word" : "byte");
>  	}
> -	dev_dbg(&client->dev,
> -		"page_size %d, num_addresses %d, write_max %d, use_smbus %d\n",
> -		chip.page_size, num_addresses,
> -		at24->write_max, use_smbus);
>  
>  	/* export data to kernel code */
>  	if (chip.setup)
> -- 
> 1.7.2.3
> 

Re: [PATCH 3/3] powerpc: pcm030/032: add pagesize to dts

[Grant Likely]

On Wed, Nov 17, 2010 at 01:00:50PM +0100, Wolfram Sang wrote:
> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

Applied for -next, thanks.

g.

> ---
>  arch/powerpc/boot/dts/pcm030.dts |    1 +
>  arch/powerpc/boot/dts/pcm032.dts |    3 ++-
>  2 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/boot/dts/pcm030.dts b/arch/powerpc/boot/dts/pcm030.dts
> index 8a4ec30..e7c36bc 100644
> --- a/arch/powerpc/boot/dts/pcm030.dts
> +++ b/arch/powerpc/boot/dts/pcm030.dts
> @@ -259,6 +259,7 @@
>  			eeprom@52 {
>  				compatible = "catalyst,24c32";
>  				reg = <0x52>;
> +				pagesize = <32>;
>  			};
>  		};
>  
> diff --git a/arch/powerpc/boot/dts/pcm032.dts b/arch/powerpc/boot/dts/pcm032.dts
> index 85d857a..e175e2c 100644
> --- a/arch/powerpc/boot/dts/pcm032.dts
> +++ b/arch/powerpc/boot/dts/pcm032.dts
> @@ -257,8 +257,9 @@
>  				reg = <0x51>;
>  			};
>  			eeprom@52 {
> -				compatible = "at24,24c32";
> +				compatible = "catalyst,24c32";
>  				reg = <0x52>;
> +				pagesize = <32>;
>  			};
>  		};
>  
> -- 
> 1.7.2.3
>