[PATCH V2 8/8] cpufreq: OMAP: donot allow to be used with device tree

Nishanth Menon
2013-03-19T17:53:10Z

We now use Soc generic cpufreq-cpu0 driver using DT entries.
However to allow cpufreq-cpu0 and omap-cpufreq drivers to co-exist,
we need to ensure the following using the same image:
1. With device tree boot, we use cpufreq-cpu0
2. With non device tree boot, we use omap-cpufreq

In the case of (1), we will have cpu OPPs and regulator registered
as part of the DT, to ensure that omap-cpufreq and cpufreq-cpu0 don't
conflict in managing the frequency of the same cpu, we should not
permit init to pass in omap-cpufreq.

In the case of (2), we will not have the cpufreq-cpu0 device, hence
only omap-cpufreq will be active.

So, to acommodate both these usage conditions, we fail init of
omap-cpufreq when we boot with device tree.

Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Jon Hunter <jon-hunter@ti.com>
Cc: "Beno√Æt Cousson" <b-cousson@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Keerthy <j-keerthy@ti.com>
Cc: linux-omap@vger.kernel.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: cpufreq@vger.kernel.org
Cc: linux-pm@vger.kernel.org

Signed-off-by: Nishanth Menon <nm@ti.com>
---
Changes in V2:
- donot remove support for omap-cpufreq in non-DT boot
- little more verbose commit log
V1: https://patchwork.kernel.org/patch/2273641/

drivers/cpufreq/omap-cpufreq.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 9128c07..9382ed0 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -22,6 +22,7 @@
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
+#include <linux/of.h>
#include <linux/opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
@@ -174,6 +175,19 @@ static inline void freq_table_free(void)
static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
{
int result = 0;
+ struct device_node *np;
+
+ /*
+ * If we have a device tree node describing OPPs,
+ * we will NOT permit usage of omap-cpufreq driver.
+ * use cpufreq-cpu0 driver to manage.
+ */
+ if (of_have_populated_dt()) {
+ for_each_child_of_node(of_find_node_by_path("/cpus"), np) {
+ if (of_get_property(np, "operating-points", NULL))
+ return -EPERM;
+ }
+ }

mpu_clk = clk_get(NULL, "cpufreq_ck");
if (IS_ERR(mpu_clk))
--
1.7.9.5