cpufreq: qoriq: enhance bus frequency calculation

On some platforms, property device-type may be missed in soc node
in dts which caused the bus-frequency can not be obtained correctly.

This patch enhanced the bus-frequency calculation. When property
device-type is missed in dts, bus-frequency will be obtained by
looking up clock table to get platform clock and hence get its
frequency.

Signed-off-by: Tang Yuantian <andy.tang@nxp.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/drivers/cpufreq/qoriq-cpufreq.c b/drivers/cpufreq/qoriq-cpufreq.c
index bfec1bcd3835..e2ea433a5f9c 100644
--- a/drivers/cpufreq/qoriq-cpufreq.c
+++ b/drivers/cpufreq/qoriq-cpufreq.c
@@ -52,17 +52,27 @@ static u32 get_bus_freq(void)
 {
         struct device_node *soc;
         u32 sysfreq;
+        struct clk *pltclk;
+        int ret;
 
+        /* get platform freq by searching bus-frequency property */
         soc = of_find_node_by_type(NULL, "soc");
-        if (!soc)
-                return 0;
-
-        if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
-                sysfreq = 0;
+        if (soc) {
+                ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
+                of_node_put(soc);
+                if (!ret)
+                        return sysfreq;
+        }
 
-        of_node_put(soc);
+        /* get platform freq by its clock name */
+        pltclk = clk_get(NULL, "cg-pll0-div1");
+        if (IS_ERR(pltclk)) {
+                pr_err("%s: can't get bus frequency %ld\n",
+                       __func__, PTR_ERR(pltclk));
+                return PTR_ERR(pltclk);
+        }
 
-        return sysfreq;
+        return clk_get_rate(pltclk);
 }
 
 static struct clk *cpu_to_clk(int cpu)