[PATCH] cpufreq: qoriq: enhance bus frequency calculation

From: YuanTian Tang
Date: Thu Mar 09 2017 - 03:30:16 EST


From: Tang Yuantian <Yuantian.Tang@xxxxxxx>

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 <yuantian.tang@xxxxxxx>
---
drivers/cpufreq/qoriq-cpufreq.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/qoriq-cpufreq.c b/drivers/cpufreq/qoriq-cpufreq.c
index bfec1bc..0f22e40 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)
--
2.1.0.27.g96db324