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>

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/cpufreq/tango-cpufreq.c b/drivers/cpufreq/tango-cpufreq.c
new file mode 100644
index 000000000000..89a7f860bfe8
--- /dev/null
+++ b/drivers/cpufreq/tango-cpufreq.c
@@ -0,0 +1,38 @@
+#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);