[PATCH v2] arm: omap: hwmod: make *phy_48m* as the main_clk of ocp2scp
paul at pwsan.com
Tue Sep 11 18:28:22 EDT 2012
Hi Kishon, Benoît,
On Fri, 7 Sep 2012, Kishon Vijay Abraham I wrote:
> Made *ocp2scp_usb_phy_phy_48m* as the main_clk for ocp2scp. Since this
> ocp2scp module does not have any fck but does have a single opt_clock,
> it is added as the main_clk for ocp2scp. Also removed phy_48m as the
> optional clock since it is now made as the main clock. By this the
> driver need not enable/disable phy_48m clk separately and
> runtime_get/runtime_put will take care of that.
Looking at this patch, it doesn't seem to make sense from a hardware point
of view. If you look at the OMAP4430 TRM Rev. AE, Table 23-1166 "Clocks
and Resets", the 48MHz clock input is listed as an "Optional functional
clock". The main functional clock is listed as "INIT_960M_FCLK", which
according to the same TRM, Section 18.104.22.168.1 "Overview", is an alias for
the clock we call "dpll_usb_clkdcoldo_ck".
So if any clock should be the main functional clock in the hwmod data,
shouldn't it be dpll_usb_clkdcoldo_ck? The goal with the hwmod data
is/was to have it match the hardware.
More to the point, I guess I don't see what the problem is with
adding a few lines to the ocp2scp driver to control the "phy_48m" optional
clock via the clock framework. Is there some reason why you
couldn't prepare & enable it after the pm_runtime_get_*(),
and disable and unprepare it before the pm_runtime_put_*() ?
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