linux_kernel/drivers/cpufreq/tango-cpufreq.c
Marc Gonzalez 9dbd224f9e cpufreq: dt: Don't use generic platdev driver for tango
On tango platforms, firmware configures the CPU clock, and Linux is
then only allowed to use the cpu_clk_divider to change the frequency.
Build the OPP table dynamically at init, in order to support whatever
firmware throws at us.

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22 02:20:59 +02:00

39 lines
927 B
C

#include <linux/of.h>
#include <linux/cpu.h>
#include <linux/clk.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
static const struct of_device_id machines[] __initconst = {
{ .compatible = "sigma,tango4" },
{ /* sentinel */ }
};
static int __init tango_cpufreq_init(void)
{
struct device *cpu_dev = get_cpu_device(0);
unsigned long max_freq;
struct clk *cpu_clk;
void *res;
if (!of_match_node(machines, of_root))
return -ENODEV;
cpu_clk = clk_get(cpu_dev, NULL);
if (IS_ERR(cpu_clk))
return -ENODEV;
max_freq = clk_get_rate(cpu_clk);
dev_pm_opp_add(cpu_dev, max_freq / 1, 0);
dev_pm_opp_add(cpu_dev, max_freq / 2, 0);
dev_pm_opp_add(cpu_dev, max_freq / 3, 0);
dev_pm_opp_add(cpu_dev, max_freq / 5, 0);
dev_pm_opp_add(cpu_dev, max_freq / 9, 0);
res = platform_device_register_data(NULL, "cpufreq-dt", -1, NULL, 0);
return PTR_ERR_OR_ZERO(res);
}
device_initcall(tango_cpufreq_init);