Hi Sylwester
You are right, no problem if clkdev is used instead of
plat-samsung/clock.c. I didn't aware of recently trend.(I couldn't
afford to having interest in open source) and I will look over clkdev
feature Thomas introduced.
Thank you.
Sylwester Nawrocki 쓴 글:
Hi Inki
On 06/20/2011 12:09 PM, daeinki wrote:
Hi, Mr. Han and Sylwester.
below is my opinion.
JinGoo Han 쓴 글:
...
Please, refer to the LCD contoller clock table as follows:
- s3c2440 uses 's3c2410fb.c', not 's3c-fb.c' since LCD controller IP is
different.
However, s3c2443 uses 's3c-fb.c'. So I add s3c2443 to table instead of
s3c2440.
- s3c6410 has SCLK_LCD, but, clock name is not defined.
- Exynos4 does not use name "HCLK".
| LCD controller | |
| (IP core) clock | LCD pixel clock |
----------+------------------------+-----------------------+
s3c2443 | HCLK (lcd) | x | DISPCLK (display-if) |
----------+------------------------+-----------------------+
s3c6410 | HCLK (lcd) | x | SCLK_LCD (N/A) |
----------+------------------------+-----------------------+
s5pc100 | HCLK (lcd) | x | SCLK_LCD (sclk_lcd) |
----------+------------------------+-----------------------+
s5pv210 | HCLK_DSYS (lcd) | x | SCLK_FIMD (sclk_fimd)|
----------+-----------------------+------------------------+
exynos4 | ACLK_160 (fimd) | O | SCLK_FIMD (sclk_fimd)|
----------+------------------------+-----------------------+
...
I think we could try to create two clock connection ids to the framebuffer
device in the first place, e.g. "bus_ck", "pix_ck".
And then think about how handle that in the driver.
But this requires conversion to the omap-style clock registration method,
something like in the attached patch. The patch is only for s5pv210 and
and compile tested only as I didn't have any board to test it here.
It's based on for-next branch at http://tinyurl.com/6yzravy I think there
might be more issues to convert the old s3c24xx platforms, nevertheless
the attached patch should not affect them.
...
when someone adds new board file with new SoC, he doesn't need to know
this SoC chip has hclk and sclk_fimd or only sclk_fimd(such as exynos4).
using implicit clock means it should know that this SoC chip has both
clocks(bus clock, sclk_fimd) or only sclk_fimd.
for example, if any driver needs fimd clock frequency then this driver
should know that this SoC chip is exynos4 or not and has both clock
source(bus clock, soure clock fimd) or not(only source clock fimd)
so I think we shoule see only a clock "lcd" regardless of which clock is
used and if exynos4 then sclk_fimd would be set by machine code.
and Sylwester,
it appears that your patch has one issue about clk_get function call.
your patch adds "bus_ck" to list head "clocks" of plat-samsung/clock.c
Why do you think so ? In fact the "clocks" list in plat-samsung/clock.c
is not used any more, AFAIU it should have been removed altogether with
clk_get/clk_put functions in Thomas' clkdev patches.
When you comment out the line declaring the list everything compiles fine
there.
and "pix_ck" to list head "clocks" of drivers/clk/clkdev.c and I am
afraid that if some machine(such as s3c24xx, s3c64xx and s5pc1xx) has
CLKDEV_LOOKUP configuration then clk_get() would fail to get clock
object because in this case, clock lookup could be done through list
head "clocks" of driver/clk/clkdev.c.(it's right from
plat-samsung/clock.c) so I think it needs more patch for resolving this
As I indicated earlier the framebuffer driver would have to be modified
to support newly introduced clock _connection_ names.
We could (temporarily) name one of those clock connections "lcd",
to avoid additional trouble on SoCs that still use a one-to-one
platform clock name <-> clock connection id mapping.
issue also and do you think it's a good way to use only one clock name
"lcd"?... in fact, this might be so.... much slight issue. :)
Do you mean using using one name in the code for different clock names
in the datasheets ? I suppose it was because of the API limitations and
hope it will change for the better. :)
Cheers,
Sylwester
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