On 20 January 2015 at 00:00, Mike Turquette [off-list ref] wrote:

Quoting pi-cheng.chen (2015-01-09 01:54:51)

quoted

diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
new file mode 100644
index 0000000..b578c10
--- /dev/null
+++ b/drivers/cpufreq/mt8173-cpufreq.c

@@ -0,0 +1,459 @@

Hello Mike,

Hello Pi-Cheng,

<snip>

quoted

+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/cpufreq.h>
+#include <linux/cpufreq-dt.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>

I'll echo what Viresh said here. CPUfreq drivers should typically be
clock consumers and only require clk.h, not clk-provider.h. More on that
below.

I included it because of the __clk_lookup call. But yes, I will use the clk_get
to get the intermediate clock to get rid of this.

<snip>

quoted

+static void cpuclk_mux_set(int cluster, u32 sel)
+{
+       u32 val;
+       u32 mask = 0x3;
+
+       if (cluster == BIG_CLUSTER) {
+               mask <<= 2;
+               sel <<= 2;
+       }
+
+       spin_lock(&lock);
+
+       val = readl(clk_mux_regs);
+       val = (val & ~mask) | sel;
+       writel(val, clk_mux_regs);
+
+       spin_unlock(&lock);
+}

Is cpuclk a mux that is represented in the MT8173 clock driver? It looks
like a clock that belong to the clock driver, but this cpufreq driver is
writing to that register directly.

Yes, it's a mux but not presented in MT8173 clock driver yet. Therefore I
map the HW register and writing them directly to do reparent. I will get
rid of it once I got those muxes presented in MT8173 clock driver.

<snip>

quoted

+static int mt8173_cpufreq_dvfs_info_init(void)
+{

<snip>

quoted

+       mainpll = __clk_lookup("mainpll");
+       if (!mainpll) {
+               pr_err("failed to get mainpll clk\n");
+               ret = -ENOENT;
+               goto dvfs_info_release;
+       }
+       mainpll_freq = clk_get_rate(mainpll);

This is definitely bad. Why not use clk_get() here? __clk_lookup should
not be exposed to clock consumer drivers (and I hope to get rid of it
completely some day).

Thanks for pointing me out the right API to do it. I will fix it in
next version.

Best Regards,
Pi-Cheng

Regards,
Mike