ARM: OMAP4: hwmod data: make 'ocp2scp_usb_phy_phy_48m" as the main clock

Commit 92702df ("ARM: OMAP4: PM: fix PM regression introduced by recent
clock cleanup") makes the 'ocp2scp_usb_phy_phy_48m' as optional
functional clock causing regression in MUSB. But this 48MHz clock is a
mandatory clock for usb phy attached to ocp2scp and hence made as the main
clock for ocp2scp.

Cc: Keerthy <j-keerthy@ti.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
[paul@pwsan.com: add comment to the hwmod data to try to prevent any
 future mistakes here]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/omap_hwmod_44xx_data.c

@@ -2714,16 +2714,22 @@ static struct omap_ocp2scp_dev ocp2scp_dev_attr[] = {
 	{ }
 };
 
-static struct omap_hwmod_opt_clk ocp2scp_usb_phy_opt_clks[] = {
-	{ .role = "48mhz", .clk = "ocp2scp_usb_phy_phy_48m" },
-};
-
 /* ocp2scp_usb_phy */
 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	= "func_48m_fclk",
+	/*
+	 * ocp2scp_usb_phy_phy_48m is provided by the OMAP4 PRCM IP
+	 * block as an "optional clock," and normally should never be
+	 * specified as the main_clk for an OMAP IP block.  However it
+	 * turns out that this clock is actually the main clock for
+	 * the ocp2scp_usb_phy IP block:
+	 * http://lists.infradead.org/pipermail/linux-arm-kernel/2012-September/119943.html
+	 * So listing ocp2scp_usb_phy_phy_48m as a main_clk here seems
+	 * to be the best workaround.
+	 */
+	.main_clk	= "ocp2scp_usb_phy_phy_48m",
 	.prcm = {
 		.omap4 = {
 			.clkctrl_offs = OMAP4_CM_L3INIT_USBPHYOCP2SCP_CLKCTRL_OFFSET,
@@ -2732,8 +2738,6 @@ static struct omap_hwmod omap44xx_ocp2scp_usb_phy_hwmod = {
 		},
 	},
 	.dev_attr	= ocp2scp_dev_attr,
-	.opt_clks	= ocp2scp_usb_phy_opt_clks,
-	.opt_clks_cnt	= ARRAY_SIZE(ocp2scp_usb_phy_opt_clks),
 };
 
 /*