On Tue, Mar 1, 2011 at 12:07 PM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
> On Tue, 2011-03-01 at 00:27 -0600, Semwal, Sumit wrote:
>> On Tue, Mar 1, 2011 at 11:49 AM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>> > On Mon, 2011-02-28 at 23:42 -0600, Semwal, Sumit wrote:
>> >> On Mon, Feb 28, 2011 at 9:33 PM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>> >> > On Mon, 2011-02-28 at 09:02 -0600, Semwal, Sumit wrote:
>> >> >> Provide a function in pdata to allow dss submodules to check if a given
>> >> >> clock is available on a platform as an optional clock.
>> >> >>
>> >> >> Signed-off-by: Senthilvadivu Guruswamy <svadivu@xxxxxx>
>> >> >> (based on implementation from Senthil)
>> >> >>
>> >> >> Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxx>
>> >> >> ---
>> >> >> arch/arm/mach-omap2/display.c | 20 ++++++++++++++++++++
>> >> >> arch/arm/plat-omap/include/plat/display.h | 2 ++
>> >> >> 2 files changed, 22 insertions(+), 0 deletions(-)
>> >> >>
>> >> >> diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
>> >> >> index 5ab6a74..9f4f862 100644
>> >> >> --- a/arch/arm/mach-omap2/display.c
>> >> >> +++ b/arch/arm/mach-omap2/display.c
>> >> >> @@ -42,6 +42,25 @@ static struct omap_device_pm_latency omap_dss_latency[] = {
>> >> >> },
>> >> >> };
>> >> >>
>> >> >> +static bool opt_clock_available(const char *clk_role)
>> >> >> +{
>> >> >> + int i;
>> >> >> + struct omap_hwmod *oh;
>> >> >> +
>> >> >> + /* opt_clks are always associated with dss hwmod */
>> >> >> + oh = omap_hwmod_lookup("dss_core");
>> >> >> + if (!oh) {
>> >> >> + pr_err("Could not look up dss_core.\n");
>> >> >> + return -ENODEV;
>> >> >
>> >> > The function returns a bool. Perhaps the lookup would be better done in
>> >> > omap_display_init(), and stored in a static variable.
>> >> Yes; I guess I should go with your earlier suggestion - of keeping
>> >> this 'oh' as part of pdata, and then use it here.
>> >
>> > I don't think it needs to be part of pdata. It's internal to this file,
>> > and if I'm not mistaken, omap_display_init() is called just once from
>> > the current board file. Thus the data could as well be stored in a
>> > static variable.
>> :) ok, that's correct; though we might need to make 'oh' part of pdata
>> based on our adaptation to the reset functionality - but that will
>> come later.
>> >
>> >> > Or if it's clear that this should never happen, BUG_ON(!oh);
>> >> Well, multiple people have 'frowned' upon using BUG_ON in dss -
>> >> especially because some people might still want their kernel to keep
>> >> working despite a display failure?
>> >
>> > Yes, BUG is an easy, not good, way out =).
>> :) hmmm... should I just return 'false' and print out a warning?
>
> From opt_clock_available() if the hwmod was not found? Well, preferably
> opt_clock_available() will never be called, if the hwmod is not found in
> omap_display_init(). So omap_display_init() should fail -> DSS driver
> refuses to start -> opt_clock_available() is never called.
:) Yes, that's true. will leave out the check then.
>
> Tomi
>
>
>
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