Re: [PATCH v4 3/3] powerpc: doc/dts-bindings: update doc of FSL I2C bindings

On Tue, Feb 9, 2010 at 12:23 PM, Wolfgang Grandegger [off-list ref] wrote:

Wolfgang Grandegger wrote:

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Hi Grant,

Grant Likely wrote:

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On Thu, Jan 28, 2010 at 6:25 AM, Wolfgang Grandegger [off-list ref] wrote:

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From: Wolfgang Grandegger <redacted>

This patch adds the MPC5121 to the list of supported devices,
enhances the doc of the "clock-frequency" property and removes
the obsolete "cell-index" property from the example nodes.
Furthermore and example for the MPC5121 has been added.

Signed-off-by: Wolfgang Grandegger <redacted>

Thanks Wolfgang.  Comments below.

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---
 Documentation/powerpc/dts-bindings/fsl/i2c.txt |   30 +++++++++++++++++++----
 1 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/Documentation/powerpc/dts-bindings/fsl/i2c.txt b/Documentation/powerpc/dts-bindings/fsl/i2c.txt
index b6d2e21..2f62dae 100644
--- a/Documentation/powerpc/dts-bindings/fsl/i2c.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/i2c.txt

@@ -9,8 +9,9 @@ Recommended properties :

 - compatible : compatibility list with 2 entries, the first should
   be "fsl,CHIP-i2c" where CHIP is the name of a compatible processor,
-   e.g. mpc8313, mpc8543, mpc8544, mpc5200 or mpc5200b. The second one
-   should be "fsl-i2c".
+   e.g. mpc8313, mpc8543, mpc8544, mpc5121, mpc5200 or mpc5200b. The
+   second one should be "fsl-i2c". For the mpc5121, an additional node
+   "fsl,mpc5121-i2c-ctrl" is required as shown in the example below.

While you're editing this line; drop the requirement for the second
value to be 'fsl-i2c'.  We don't use it anymore, and only preserve it
for backwards compatibility with old trees.

OK.

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 - interrupts : <a b> where a is the interrupt number and b is a
   field that represents an encoding of the sense and level
   information for the interrupt.  This should be encoded based on

@@ -20,29 +21,46 @@ Recommended properties :

   services interrupts for this device.
 - fsl,preserve-clocking : boolean; if defined, the clock settings
   from the bootloader are preserved (not touched).
- - clock-frequency : desired I2C bus clock frequency in Hz.
+ - clock-frequency : desired I2C bus clock frequency in Hz.  If this
+   property and "fsl,preserve-clocking" is not defined, a safe fixed
+   clock divider value is used (resulting in a small clock frequency).

Nah, leave this as is.  Don't make it sound like omitting both
properties is a valid option.  The driver may (and should!) handle the
situation gracefully, but that fact does not need to be documented.

The safe value is not a good choice, indeed. Then it will also change
MPC_I2C_CLOCK_SAFE to MPC_I2C_CLOCK_LEGACY in i2c-mpc.c.

I will also fix the other issues you commented on.

And I will also remove the "device_type" line from:

 -------------
 Required properties :

 - device_type : Should be "i2c"
 - reg : Offset and length of the register set for the device

Yes, please.

Hmmm.  compatible should also be in the 'required properties' section.

Thanks,
g.