omap cpufreq driver in multi-platform kernels

[Paul Walmsley]

Hi

On Tue, 26 Mar 2013, Rob Herring wrote:

> The omap cpufreq driver causes problems in multi-platform kernels
> because it unconditionally registers with the cpufreq core and does not
> check sufficiently that it is running on an omap platform. So on a
> kernel with highbank and omap drivers booted on highbank, the
> cpufreq-cpu0 driver fails to init. Any suggestions for how to fix? For
> DT this could just be several of_machine_is_compatible checks, but I'm
> not really sure for non-DT. Converting the driver to a platform driver
> would be another option.

We could move the

	mpu_clk = clk_get(NULL, "cpufreq_ck");

down to omap_cpufreq_init(), and bail out early if the clock alias doesn't 
exist.  (Presumably we'd also want to change the clock role name if we did 
that, to something like "omap_cpufreq_ck".)

Experimental patch follows, comments welcome.


- Paul

>From c1b4374d9cdcf59e0cbe93aa5a23335cb3e60798 Mon Sep 17 00:00:00 2001
From: Paul Walmsley <paul at pwsan.com>
Date: Tue, 26 Mar 2013 20:16:39 -0600
Subject: [PATCH] EXPERIMENTAL: cpufreq: avoid loading the OMAP driver on
 non-OMAP multiplatform targets

etc. etc.
---
 arch/arm/mach-omap2/cclock2420_data.c |    2 +-
 arch/arm/mach-omap2/cclock2430_data.c |    2 +-
 arch/arm/mach-omap2/cclock3xxx_data.c |    2 +-
 arch/arm/mach-omap2/cclock44xx_data.c |    2 +-
 drivers/cpufreq/omap-cpufreq.c        |    8 ++++----
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-omap2/cclock2420_data.c b/arch/arm/mach-omap2/cclock2420_data.c
index 0f0a97c..d4316e9 100644
--- a/arch/arm/mach-omap2/cclock2420_data.c
+++ b/arch/arm/mach-omap2/cclock2420_data.c
@@ -1885,7 +1885,7 @@ static struct omap_clk omap2420_clks[] = {
 	CLK(NULL,	"timer_32k_ck",	&func_32k_ck,	CK_242X),
 	CLK(NULL,	"timer_sys_ck",	&sys_ck,	CK_242X),
 	CLK(NULL,	"timer_ext_ck",	&alt_ck,	CK_242X),
-	CLK(NULL,	"cpufreq_ck",	&virt_prcm_set,	CK_242X),
+	CLK(NULL,	"omap_cpufreq_ck",	&virt_prcm_set,	CK_242X),
 };
 
 
diff --git a/arch/arm/mach-omap2/cclock2430_data.c b/arch/arm/mach-omap2/cclock2430_data.c
index aed8f74..7c855b9 100644
--- a/arch/arm/mach-omap2/cclock2430_data.c
+++ b/arch/arm/mach-omap2/cclock2430_data.c
@@ -2001,7 +2001,7 @@ static struct omap_clk omap2430_clks[] = {
 	CLK(NULL,	"timer_32k_ck",  &func_32k_ck,   CK_243X),
 	CLK(NULL,	"timer_sys_ck",	&sys_ck,	CK_243X),
 	CLK(NULL,	"timer_ext_ck",	&alt_ck,	CK_243X),
-	CLK(NULL,	"cpufreq_ck",	&virt_prcm_set,	CK_243X),
+	CLK(NULL,	"omap_cpufreq_ck",	&virt_prcm_set,	CK_243X),
 };
 
 static const char *enable_init_clks[] = {
diff --git a/arch/arm/mach-omap2/cclock3xxx_data.c b/arch/arm/mach-omap2/cclock3xxx_data.c
index 4579c3c..17dd82c 100644
--- a/arch/arm/mach-omap2/cclock3xxx_data.c
+++ b/arch/arm/mach-omap2/cclock3xxx_data.c
@@ -3501,7 +3501,7 @@ static struct omap_clk omap3xxx_clks[] = {
 	CLK(NULL,	"uart4_ick",	&uart4_ick_am35xx,	CK_AM35XX),
 	CLK(NULL,	"timer_32k_ck",	&omap_32k_fck,  CK_3XXX),
 	CLK(NULL,	"timer_sys_ck",	&sys_ck,	CK_3XXX),
-	CLK(NULL,	"cpufreq_ck",	&dpll1_ck,	CK_3XXX),
+	CLK(NULL,	"omap_cpufreq_ck",	&dpll1_ck,	CK_3XXX),
 };
 
 static const char *enable_init_clks[] = {
diff --git a/arch/arm/mach-omap2/cclock44xx_data.c b/arch/arm/mach-omap2/cclock44xx_data.c
index 3d58f33..66b85e5 100644
--- a/arch/arm/mach-omap2/cclock44xx_data.c
+++ b/arch/arm/mach-omap2/cclock44xx_data.c
@@ -1660,7 +1660,7 @@ static struct omap_clk omap44xx_clks[] = {
 	CLK("4013a000.timer",	"timer_sys_ck",	&syc_clk_div_ck,	CK_443X),
 	CLK("4013c000.timer",	"timer_sys_ck",	&syc_clk_div_ck,	CK_443X),
 	CLK("4013e000.timer",	"timer_sys_ck",	&syc_clk_div_ck,	CK_443X),
-	CLK(NULL,	"cpufreq_ck",	&dpll_mpu_ck,	CK_443X),
+	CLK(NULL,	"omap_cpufreq_ck",	&dpll_mpu_ck,	CK_443X),
 };
 
 int __init omap4xxx_clk_init(void)
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 9128c07..d46caa5 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -175,10 +175,6 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 {
 	int result = 0;
 
-	mpu_clk = clk_get(NULL, "cpufreq_ck");
-	if (IS_ERR(mpu_clk))
-		return PTR_ERR(mpu_clk);
-
 	if (policy->cpu >= NR_CPUS) {
 		result = -EINVAL;
 		goto fail_ck;
@@ -254,6 +250,10 @@ static struct cpufreq_driver omap_driver = {
 
 static int __init omap_cpufreq_init(void)
 {
+	mpu_clk = clk_get(NULL, "omap_cpufreq_ck");
+	if (IS_ERR(mpu_clk))
+		return PTR_ERR(mpu_clk);
+
 	mpu_dev = get_cpu_device(0);
 	if (!mpu_dev) {
 		pr_warning("%s: unable to get the mpu device\n", __func__);
-- 
1.7.10.4