On Thu, Aug 02, 2012 at 18:42:50, Russell King - ARM Linux wrote:
> On Thu, Aug 02, 2012 at 01:04:37PM +0000, Hiremath, Vaibhav wrote:
> > On Wed, Aug 01, 2012 at 19:44:14, Russell King - ARM Linux wrote:
> > > On Wed, Aug 01, 2012 at 05:50:16PM +0530, Vaibhav Hiremath wrote:
> > > > The clk_get() api will not work, unless we pass both the arguments (dev,
> > > > con_id) properly. Now expecting driver to always label con_id with "fck"
> > > > is undesirable, as the same driver can be reused on multiple platforms,
> > > > which can be non-omap and/or non-ti platforms.
> > >
> > > Why not?
> > >
> > > The connection ID is defined by the driver, and the platform stuff is
> > > expected to provide drivers with what they require. It's not the other
> > > way around (platforms don't tell drivers what they require.)
> > >
> > > In other words, if the device has two clocks, one called ick and one called
> > > fck, then the device _should_ use clk_get() specifying "ick" for one, and
> > > "fck" for the other.
> > >
> > > And platforms better provide an "ick" and a "fck" for the device, even if
> > > they have no respresentation for one or other of them (in which case you
> > > supply a dummy clock.)
> > >
> >
> > Russell, I completely agree with you, infact I am on the same page.
> > Let me give you a real example, which I am dealing with now,
> >
> > On AM335x device we have integrated DCAN, this IP is not from TI.
> > IP is from Bosch and doesn't follow any of the TI IP standards, like
> > HighLander spec. The IP is just integrated with interconnect bus and given a
> > required clocksource (in this case its one clock).
> >
> > The driver for this IP is generic, (drivers/net/can/c_can/c_can_platform.c)
> > obviously used across non-ti devices already and driver is implemented with,
> > clk_get(dev, NULL);
>
> So, elsewhere it only has one clock. Are there any other clocks it needs
> on OMAP?
>
> If the answer is no, then the driver is doing the right thing, and OMAP's
> clk stuff needs to be adjusted to suit the drivers requirements.
>
> I've said many times over the years that clock connection IDs are defined
> by the device or driver and *nothing* else - they're certainly *not* source
> names.
>
> That's why, when I modified OMAP drivers to fix them, and they take an
> interface and function clock, they end up asking for "ick" and "fck" not
> "blah_ick" and "blah_fck".
>
I am in agreement with you and I believe I came to the solution for this
issue, I used "of_dev_auxdata" to manipulate dev_id and updated clock-tree
table with required clock entry and it works, I tried it on BeagleBone
platform.
Can you please review it?
diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
index 6f93a20..893cc0c 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -37,11 +37,24 @@ 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.
+ */
+static const struct of_dev_auxdata omap_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),
+ { },
+};
+
+
static void __init omap_generic_init(void)
{
omap_sdrc_init(NULL, NULL);
- of_platform_populate(NULL, omap_dt_match_table, NULL, NULL);
+ of_platform_populate(NULL, omap_dt_match_table, omap_auxdata_lookup, NULL);
}
#ifdef CONFIG_SOC_OMAP2420
diff --git a/arch/arm/mach-omap2/clock33xx_data.c b/arch/arm/mach-omap2/clock33xx_data.c
index ae27de8..f061834 100644
--- a/arch/arm/mach-omap2/clock33xx_data.c
+++ b/arch/arm/mach-omap2/clock33xx_data.c
@@ -1028,6 +1028,8 @@ static struct omap_clk am33xx_clks[] = {
CLK(NULL, "clkdiv32k_ick", &clkdiv32k_ick, CK_AM33XX),
CLK(NULL, "dcan0_fck", &dcan0_fck, CK_AM33XX),
CLK(NULL, "dcan1_fck", &dcan1_fck, CK_AM33XX),
+ CLK("d_can.0", NULL, &dcan0_fck, CK_AM33XX),
+ CLK("d_can.1", NULL, &dcan1_fck, CK_AM33XX),
CLK(NULL, "debugss_ick", &debugss_ick, CK_AM33XX),
CLK(NULL, "pruss_ocp_gclk", &pruss_ocp_gclk, CK_AM33XX),
CLK("davinci-mcasp.0", NULL, &mcasp0_fck, CK_AM33XX),
--
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