[PATCH] ARM: AM33XX: board-generic: Add of_dev_auxdata to fix dev_id for CAN module

Op 7 aug. 2012, om 17:53 heeft "Hiremath, Vaibhav" [off-list ref] het volgende geschreven:

On Tue, Aug 07, 2012 at 20:49:48, Rob Herring wrote:

quoted

On 08/07/2012 08:37 AM, Vaibhav Hiremath wrote:

quoted

If the module requires only one clocksource to function, then
driver can very well call clk_get() api with "con_id = NULL",

      clk = clk_get(dev, NULL);

And platform code should respect this and return valid clk handle.
That means, now the clk_get() api would rely on dev_id, and platform
code should either have clk node with matching dev_id (with con_id=NULL)
or return dummy clk node.

With DT support, we can fix the dev_id for particular module
using "struct of_dev_auxdata" to satisfy above clk framework requirement.

In case of AM33XX, we required this for the DCAN module, so this
patch adds "of_dev_auxdata" for both DCAN_0/1 instances.

Signed-off-by: Vaibhav Hiremath <redacted>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <redacted>
Cc: Grant Likely <redacted>
---
This patch is boot tested on BeagleBone platform, and checked for
clk_get() return value in d_can module driver.

arch/arm/mach-omap2/board-generic.c |   18 +++++++++++++++++-
1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
index 6f93a20..c9b7903 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c

@@ -37,11 +37,27 @@ static struct of_device_id omap_dt_match_table[] __initdata = {

	{ }
};

+/*
+ * Lookup table for attaching a specific name and platform_data pointer to
+ * devices as they get created by of_platform_populate(). Ideally this table
+ * would not exist, but the current clock implementation depends on some devices
+ * having a specific name OR to satisfy NULL con_id requirement from driver.
+ */
+static const struct of_dev_auxdata am33xx_auxdata_lookup[] __initconst = {
+	OF_DEV_AUXDATA("bosch,d_can", 0x481cc000, "d_can.0", NULL),
+	OF_DEV_AUXDATA("bosch,d_can", 0x481d0000, "d_can.1", NULL),
+	{ },
+};

Adding an additional clkdev lookup accomplishes the same thing and is a
cleaner solution.

That is also required and I have submitted patch for the same -

http://www.spinics.net/lists/arm-kernel/msg187998.html


With DT support, I am getting dev_id as -

- Without "reg" property: d_can.16 and d_can.17,
  (I believe it changes dynamically here)

- With "reg" property: 481cc000.d_can and 481d0000.d_can

Which is not so intuitive, I would like to see them as per Spec/TRM, so 
doesn't this patch make sense?

Similar thing has already been done for other platforms too.

Davinci-mdio has a similar problem

regards,

Koen