Patchwork [v2] arm: omap: hwmod: make *phy_48m* as the main_clk of ocp2scp

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Submitter Kishon Vijay Abraham I
Date Sept. 7, 2012, 9:09 a.m.
Message ID <1347008955-21310-1-git-send-email-kishon@ti.com>
Download mbox | patch
Permalink /patch/182346/
State New
Headers show

Comments

Kishon Vijay Abraham I - Sept. 7, 2012, 9:09 a.m.
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.

Cc: Benoît Cousson <b-cousson@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
Changes for v1:
 Amend the comment section with benefit for the driver because of this patch.
 arch/arm/mach-omap2/omap_hwmod_44xx_data.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)
Paul Walmsley - Sept. 11, 2012, 10:28 p.m.
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 3.6.3.9.1 "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_*() ?


- Paul
Kishon Vijay Abraham I - Sept. 12, 2012, 6:36 a.m.
Hi,

On Wed, Sep 12, 2012 at 3:58 AM, Paul Walmsley <paul@pwsan.com> wrote:
> 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 3.6.3.9.1 "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

It should be added in omap-usb2 driver rather.
> 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_*() ?

We have omap-usb2 driver that is used for both omap4 and omap5. But
this 48m clock is used only in omap4. And we dint have any *main_clk*
in the ocp2scp_usb_phy_hwmod. So in order avoid some checks in the
omap-usb2 driver, we added 48m clk as the main clock of
ocp2scp_usb_phy_hwmod.

Thanks
Kishon
Cousson, Benoit - Sept. 13, 2012, 4:16 p.m.
Hi Paul,

On 09/12/2012 12:28 AM, Paul Walmsley wrote:
> 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 3.6.3.9.1 "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.

In this case, the ocp2scp IP is just the *bus controller* to access the
real USB_UTMI_PHY IP.

The TRM diagram does not show that level of detail unfortunately. You
can check the PRCM spec (Figure 78 : CD_L3_INIT_USB clock scheme) to see
the two modules.

So considering phy_48m as the main clock is still correct for the
ocp2scp IP.

The INIT_960M_FCLK will be a fck associated with the child of the
ocp2scp nodes which is the usb_phy.

Upgrading the opt_clk to fck does make sense as soon as we don't have
any other functional clock and as soon as this clock is *mandatory*. The
optional aspect in that case is just a wrong PRCM naming for a clock
that is mandatory. It is similar to the DSS case that does have only
optional clocks that are mandatory.

I do agree that we must stick to the HW definition as far as we can. But
the optional attribute is something that is wrong/inaccurate for a
couple of IPs. HW folks agreed on that point and will fix that in the
future.

Regards,
Benoit
Paul Walmsley - Sept. 13, 2012, 5:10 p.m.
On Thu, 13 Sep 2012, Benoit Cousson wrote:

> In this case, the ocp2scp IP is just the *bus controller* to access the
> real USB_UTMI_PHY IP.
> 
> The TRM diagram does not show that level of detail unfortunately. You
> can check the PRCM spec (Figure 78 : CD_L3_INIT_USB clock scheme) to see
> the two modules.
> 
> So considering phy_48m as the main clock is still correct for the
> ocp2scp IP.
> 
> The INIT_960M_FCLK will be a fck associated with the child of the
> ocp2scp nodes which is the usb_phy.
> 
> Upgrading the opt_clk to fck does make sense as soon as we don't have
> any other functional clock and as soon as this clock is *mandatory*. The
> optional aspect in that case is just a wrong PRCM naming for a clock
> that is mandatory. It is similar to the DSS case that does have only
> optional clocks that are mandatory.
> 
> I do agree that we must stick to the HW definition as far as we can. But
> the optional attribute is something that is wrong/inaccurate for a
> couple of IPs. HW folks agreed on that point and will fix that in the
> future.

Okay so is this an Acked-by for this patch? :-)

If so I'll take it.


- Paul
Paul Walmsley - Sept. 13, 2012, 7:53 p.m.
On Thu, 13 Sep 2012, Paul Walmsley wrote:

> Okay so is this an Acked-by for this patch? :-)
> 
> If so I'll take it.

Just realized that's what your reply was, so have queued the patch for 
3.7.


- Paul

Patch

diff --git a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
index 242aee4..e8e5405 100644
--- a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
@@ -2503,14 +2503,11 @@  static struct omap_hwmod_class omap44xx_ocp2scp_hwmod_class = {
 };
 
 /* ocp2scp_usb_phy */
-static struct omap_hwmod_opt_clk ocp2scp_usb_phy_opt_clks[] = {
-	{ .role = "phy_48m", .clk = "ocp2scp_usb_phy_phy_48m" },
-};
-
 static struct omap_hwmod omap44xx_ocp2scp_usb_phy_hwmod = {
 	.name		= "ocp2scp_usb_phy",
 	.class		= &omap44xx_ocp2scp_hwmod_class,
 	.clkdm_name	= "l3_init_clkdm",
+	.main_clk	= "ocp2scp_usb_phy_phy_48m",
 	.prcm = {
 		.omap4 = {
 			.clkctrl_offs = OMAP4_CM_L3INIT_USBPHYOCP2SCP_CLKCTRL_OFFSET,
@@ -2518,8 +2515,6 @@  static struct omap_hwmod omap44xx_ocp2scp_usb_phy_hwmod = {
 			.modulemode   = MODULEMODE_HWCTRL,
 		},
 	},
-	.opt_clks	= ocp2scp_usb_phy_opt_clks,
-	.opt_clks_cnt	= ARRAY_SIZE(ocp2scp_usb_phy_opt_clks),
 };
 
 /*