Hi Rob,

On 12/14/2011 5:58 PM, Rob Herring wrote:
Benoit,

On 12/09/2011 08:02 AM, Benoit Cousson wrote:
Add initial DT support to retrieve the frequency using a
DT attribute instead of the pdata pointer if of_node exist.

Add documentation for omap i2c controller binding.

Based on original patches from Manju and Grant.

Signed-off-by: Benoit Cousson<b-cous...@ti.com>
Cc: Ben Dooks<ben-li...@fluff.org>
---
  Documentation/devicetree/bindings/i2c/omap-i2c.txt |   42 ++++++++
  drivers/i2c/busses/i2c-omap.c                      |  100 +++++++++++++-------
  2 files changed, 107 insertions(+), 35 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/i2c/omap-i2c.txt

diff --git a/Documentation/devicetree/bindings/i2c/omap-i2c.txt 
b/Documentation/devicetree/bindings/i2c/omap-i2c.txt
new file mode 100644
index 0000000..d259a17
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/omap-i2c.txt
@@ -0,0 +1,42 @@
+I2C for OMAP platforms
+
+Required properties :
+- compatible : Must be "ti,omap3-i2c" or "ti,omap4-i2c"
+- ti,hwmods : Must be "i2c<n>", n being the instance number (1-based)
+- #address-cells =<1>;
+- #size-cells =<0>;
+
+Recommended properties :
+- clock-frequency : Desired I2C bus clock frequency in Hz. Otherwise
+  the default 100 kHz frequency will be used.
+
+Optional properties:
+- Child nodes conforming to i2c bus binding
+- ti,flags : u32: settings or errata relative to the i2c
+    0x1:   OMAP_I2C_FLAG_NO_FIFO
+    0x2:   OMAP_I2C_FLAG_SIMPLE_CLOCK
+    0x4:   OMAP_I2C_FLAG_16BIT_DATA_REG
+    0x8:   OMAP_I2C_FLAG_RESET_REGS_POSTIDLE
+    0x10:  OMAP_I2C_FLAG_APPLY_ERRATA_I207
+    0x20:  OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK
+    0x40:  OMAP_I2C_FLAG_FORCE_19200_INT_CLK
+  Valid for ti,omap3-i2c only:
+    0x80:  OMAP_I2C_FLAG_BUS_SHIFT_1: 8 bits registers
+    0x100: OMAP_I2C_FLAG_BUS_SHIFT_2: 16 bits registers

It's generally preferred to split these out to separate properties since
there is not yet define capability in dts.

Yeah, I was hoping that Stephen's DTC patches were accepted to avoid that.

Can some of these be removed
by having more specific compatible strings? That is the whole point in
having compatible strings not be generic. omap4-i2c and omap3-i2c is
still kind of generic.

Do you mean creating some attributes like that:

+    ti,16bits_shift;
+    ti,reset_postidle;
+    ti,errata_i207;

Or using some omap3-i2c or omap4-i2c to determine the proper version and thus populate the right flags during probe.

[...]

@@ -965,6 +956,31 @@ static const struct i2c_algorithm omap_i2c_algo = {
        .functionality  = omap_i2c_func,
  };

+#ifdef CONFIG_OF
+static struct omap_i2c_bus_platform_data omap3_pdata = {
+       .rev = OMAP_I2C_IP_VERSION_1,
+};
+
+static struct omap_i2c_bus_platform_data omap4_pdata = {
+       .rev = OMAP_I2C_IP_VERSION_2,
+};

This is redundant. The ip version can be determined from the compatible
string.

I'm confused...
I'm using the compatible string below to chose the proper value.
This flag is then used later at runtime.
I'm using a pseudo pdata because that driver is still used in old platform that does and will never not have DT support.

+static const struct of_device_id omap_i2c_of_match[] = {
+       {
+               .compatible = "ti,omap4-i2c",
+               .data =&omap4_pdata,
+       },
+       {
+               .compatible = "ti,omap3-i2c",
+               .data =&omap3_pdata,
+       },
+       { },
+};
+MODULE_DEVICE_TABLE(of, omap_i2c_of_match);
+#else
+#define omap_i2c_of_match NULL

Use of_match_ptr instead of the #else.

OK, good point.

Thanks,
Benoit
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