revision1

From 1320fe9f83c69ae3676d6411ddd724a6ffebbeac Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@ti.com>
Date: Fri, 15 Mar 2013 12:03:30 -0500
Subject: [PATCH] ARM: OMAP3+: use cpu0-cpufreq driver in device tree
 supported boot

With OMAP3+ and AM33xx supported SoC having defined CPU device tree
entries with operating-points defined, we can now use the SoC
generic cpufreq-cpu0 driver by registering appropriate device.

OMAP clock nodes are not represented by device tree nodes yet.
Once the OMAP device tree conversion is complete, we should
have been able to do:
clocks = <&dpll_mpu_ck>; or the SoC specific equivalent.

However, since we are unable to do the same, use "cpufreq_ck"
as an generic clock alias to point at the representative
clock required for controlling CPU clock.

As part of this change modify AM33xx clock data file to
have cpufreq_ck clock to be generic. This way both omap-cpufreq
and cpufreq-cpu0 drivers (based on device tree enabled boot support)
will use the same clock alias.

For platforms which get clock nodes converted into DT, they need to
make a cpufreq_ck clock available.
Once complete DT conversion is complete, cpufreq_ck DT clock nodes
can be deleted with corresponding change in code.

Inspired by patch: https://patchwork.kernel.org/patch/2067841/
now made generic.

Nyet-signed-off-by: Nishanth Menon <nm@ti.com>
---
 arch/arm/mach-omap2/board-generic.c   |   37 +++++++++++++++++++++++++++++++++
 arch/arm/mach-omap2/cclock33xx_data.c |    2 +-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
index afa509a..b32dd55 100644
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -11,6 +11,7 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
@@ -35,6 +36,40 @@ static struct of_device_id omap_dt_match_table[] __initdata = {
 	{ }
 };

+static void omap_generic_cpufreq_init(void)
+{
+	struct platform_device *pdev;
+	struct platform_device_info devinfo = { .name = "cpufreq-cpu0", };
+	char cpufreq_ck_name[] = "cpufreq_ck";
+	int r;
+
+	if (!IS_ENABLED(CONFIG_GENERIC_CPUFREQ_CPU0))
+		return;
+
+	pdev = platform_device_register_full(&devinfo);
+	if (IS_ERR(pdev)) {
+		pr_err("%s: failed to register %s device\n", __func__,
+		       devinfo.name);
+		return;
+	}
+
+	/*
+	 * XXX: FIXME:
+	 * OMAP clock nodes are still based off data files. When they get
+	 * converted to DT entries, cpu node should have a clock node associated
+	 * with it.
+	 * We expect cpufreq to continue to work seamlessly when that takes
+	 * place. When that takes place, remove the following code:
+	 */
+	r = clk_add_alias(NULL, dev_name(&pdev->dev), cpufreq_ck_name,
+			  &pdev->dev);
+	if (r) {
+		dev_err(&pdev->dev, "%s: clk add alias '%s' failed(%d)\n",
+			__func__, cpufreq_ck_name, r);
+		platform_device_unregister(pdev);
+	}
+}
+
 static void __init omap_generic_init(void)
 {
 	omap_sdrc_init(NULL, NULL);
@@ -49,6 +84,8 @@ static void __init omap_generic_init(void)
 		omap4_panda_display_init_of();
 	else if (of_machine_is_compatible("ti,omap4-sdp"))
 		omap_4430sdp_display_init_of();
+
+	omap_generic_cpufreq_init();
 }

 #ifdef CONFIG_SOC_OMAP2420
diff --git a/arch/arm/mach-omap2/cclock33xx_data.c b/arch/arm/mach-omap2/cclock33xx_data.c
index 476b820..262cee3 100644
--- a/arch/arm/mach-omap2/cclock33xx_data.c
+++ b/arch/arm/mach-omap2/cclock33xx_data.c
@@ -852,7 +852,7 @@ static struct omap_clk am33xx_clks[] = {
 	CLK(NULL,	"dpll_core_m5_ck",	&dpll_core_m5_ck,	CK_AM33XX),
 	CLK(NULL,	"dpll_core_m6_ck",	&dpll_core_m6_ck,	CK_AM33XX),
 	CLK(NULL,	"dpll_mpu_ck",		&dpll_mpu_ck,	CK_AM33XX),
-	CLK("cpu0",	NULL,			&dpll_mpu_ck,	CK_AM33XX),
+	CLK(NULL,	"cpufreq_ck",			&dpll_mpu_ck,	CK_AM33XX),
 	CLK(NULL,	"dpll_mpu_m2_ck",	&dpll_mpu_m2_ck,	CK_AM33XX),
 	CLK(NULL,	"dpll_ddr_ck",		&dpll_ddr_ck,	CK_AM33XX),
 	CLK(NULL,	"dpll_ddr_m2_ck",	&dpll_ddr_m2_ck,	CK_AM33XX),
--
1.7.9.5