[PATCH 2/2] cpufreq: add cpufreq driver for Mediatek MT8173 SoC
Mike Turquette
mturquette at linaro.org
Mon Jan 19 08:00:39 PST 2015
Quoting pi-cheng.chen (2015-01-09 01:54:51)
> 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 Pi-Cheng,
<snip>
> +#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.
<snip>
> +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.
<snip>
> +static int mt8173_cpufreq_dvfs_info_init(void)
> +{
<snip>
> + 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).
Regards,
Mike
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